fix golint issues (#535)

* fix golint issues in core/utils

* fix golint issues in core/trace

* fix golint issues in core/trace

core/bloom/bloom.go

@@ -27,43 +27,43 @@ return true
 `
 )
 
+// ErrTooLargeOffset indicates the offset is too large in bitset.
 var ErrTooLargeOffset = errors.New("too large offset")
 
 type (
-	BitSetProvider interface {
+	// A Filter is a bloom filter.
+	Filter struct {
+		bits   uint
+		bitSet bitSetProvider
+	}
+
+	bitSetProvider interface {
 		check([]uint) (bool, error)
 		set([]uint) error
 	}
-
-	BloomFilter struct {
-		bits   uint
-		bitSet BitSetProvider
-	}
 )
 
-// New create a BloomFilter, store is the backed redis, key is the key for the bloom filter,
+// New create a Filter, store is the backed redis, key is the key for the bloom filter,
 // bits is how many bits will be used, maps is how many hashes for each addition.
 // best practices:
 // elements - means how many actual elements
 // when maps = 14, formula: 0.7*(bits/maps), bits = 20*elements, the error rate is 0.000067 < 1e-4
 // for detailed error rate table, see http://pages.cs.wisc.edu/~cao/papers/summary-cache/node8.html
-func New(store *redis.Redis, key string, bits uint) *BloomFilter {
-	return &BloomFilter{
+func New(store *redis.Redis, key string, bits uint) *Filter {
+	return &Filter{
 		bits:   bits,
 		bitSet: newRedisBitSet(store, key, bits),
 	}
 }
 
-func (f *BloomFilter) Add(data []byte) error {
+// Add adds data into f.
+func (f *Filter) Add(data []byte) error {
 	locations := f.getLocations(data)
-	err := f.bitSet.set(locations)
-	if err != nil {
-		return err
-	}
-	return nil
+	return f.bitSet.set(locations)
 }
 
-func (f *BloomFilter) Exists(data []byte) (bool, error) {
+// Exists checks if data is in f.
+func (f *Filter) Exists(data []byte) (bool, error) {
 	locations := f.getLocations(data)
 	isSet, err := f.bitSet.check(locations)
 	if err != nil {
@@ -76,7 +76,7 @@ func (f *BloomFilter) Exists(data []byte) (bool, error) {
 	return true, nil
 }
 
-func (f *BloomFilter) getLocations(data []byte) []uint {
+func (f *Filter) getLocations(data []byte) []uint {
 	locations := make([]uint, maps)
 	for i := uint(0); i < maps; i++ {
 		hashValue := hash.Hash(append(data, byte(i)))
@@ -127,11 +127,12 @@ func (r *redisBitSet) check(offsets []uint) (bool, error) {
 		return false, err
 	}
 
-	if exists, ok := resp.(int64); !ok {
+	exists, ok := resp.(int64)
+	if !ok {
 		return false, nil
-	} else {
-		return exists == 1, nil
 	}
+
+	return exists == 1, nil
 }
 
 func (r *redisBitSet) del() error {
@@ -152,7 +153,7 @@ func (r *redisBitSet) set(offsets []uint) error {
 	_, err = r.store.Eval(setScript, []string{r.key}, args)
 	if err == redis.Nil {
 		return nil
-	} else {
-		return err
 	}
+
+	return err
 }

core/breaker/breaker.go

@@ -18,12 +18,14 @@ const (
 	timeFormat        = "15:04:05"
 )
 
-// ErrServiceUnavailable is returned when the CB state is open
+// ErrServiceUnavailable is returned when the Breaker state is open.
 var ErrServiceUnavailable = errors.New("circuit breaker is open")
 
 type (
+	// Acceptable is the func to check if the error can be accepted.
 	Acceptable func(err error) bool
 
+	// A Breaker represents a circuit breaker.
 	Breaker interface {
 		// Name returns the name of the Breaker.
 		Name() string
@@ -61,10 +63,14 @@ type (
 		DoWithFallbackAcceptable(req func() error, fallback func(err error) error, acceptable Acceptable) error
 	}
 
+	// Option defines the method to customize a Breaker.
 	Option func(breaker *circuitBreaker)
 
+	// Promise interface defines the callbacks that returned by Breaker.Allow.
 	Promise interface {
+		// Accept tells the Breaker that the call is successful.
 		Accept()
+		// Reject tells the Breaker that the call is failed.
 		Reject(reason string)
 	}
 
@@ -89,6 +95,8 @@ type (
 	}
 )
 
+// NewBreaker returns a Breaker object.
+// opts can be used to customize the Breaker.
 func NewBreaker(opts ...Option) Breaker {
 	var b circuitBreaker
 	for _, opt := range opts {
@@ -127,6 +135,7 @@ func (cb *circuitBreaker) Name() string {
 	return cb.name
 }
 
+// WithName returns a function to set the name of a Breaker.
 func WithName(name string) Option {
 	return func(b *circuitBreaker) {
 		b.name = name

core/breaker/breakers.go

@@ -7,24 +7,28 @@ var (
 	breakers = make(map[string]Breaker)
 )
 
+// Do calls Breaker.Do on the Breaker with given name.
 func Do(name string, req func() error) error {
 	return do(name, func(b Breaker) error {
 		return b.Do(req)
 	})
 }
 
+// DoWithAcceptable calls Breaker.DoWithAcceptable on the Breaker with given name.
 func DoWithAcceptable(name string, req func() error, acceptable Acceptable) error {
 	return do(name, func(b Breaker) error {
 		return b.DoWithAcceptable(req, acceptable)
 	})
 }
 
+// DoWithFallback calls Breaker.DoWithFallback on the Breaker with given name.
 func DoWithFallback(name string, req func() error, fallback func(err error) error) error {
 	return do(name, func(b Breaker) error {
 		return b.DoWithFallback(req, fallback)
 	})
 }
 
+// DoWithFallbackAcceptable calls Breaker.DoWithFallbackAcceptable on the Breaker with given name.
 func DoWithFallbackAcceptable(name string, req func() error, fallback func(err error) error,
 	acceptable Acceptable) error {
 	return do(name, func(b Breaker) error {
@@ -32,6 +36,7 @@ func DoWithFallbackAcceptable(name string, req func() error, fallback func(err e
 	})
 }
 
+// GetBreaker returns the Breaker with the given name.
 func GetBreaker(name string) Breaker {
 	lock.RLock()
 	b, ok := breakers[name]
@@ -51,7 +56,8 @@ func GetBreaker(name string) Breaker {
 	return b
 }
 
-func NoBreakFor(name string) {
+// NoBreakerFor disables the circuit breaker for the given name.
+func NoBreakerFor(name string) {
 	lock.Lock()
 	breakers[name] = newNoOpBreaker()
 	lock.Unlock()

core/breaker/breakers_test.go

@@ -55,7 +55,7 @@ func TestBreakersDoWithAcceptable(t *testing.T) {
 }
 
 func TestBreakersNoBreakerFor(t *testing.T) {
-	NoBreakFor("any")
+	NoBreakerFor("any")
 	errDummy := errors.New("any")
 	for i := 0; i < 10000; i++ {
 		assert.Equal(t, errDummy, GetBreaker("any").Do(func() error {

core/breaker/googlebreaker.go

@@ -64,9 +64,9 @@ func (b *googleBreaker) doReq(req func() error, fallback func(err error) error,
 	if err := b.accept(); err != nil {
 		if fallback != nil {
 			return fallback(err)
-		} else {
-			return err
 		}
+
+		return err
 	}
 
 	defer func() {

core/cmdline/input.go

@@ -7,11 +7,13 @@ import (
 	"strings"
 )
 
+// EnterToContinue let stdin waiting for an enter key to continue.
 func EnterToContinue() {
 	fmt.Print("Press 'Enter' to continue...")
 	bufio.NewReader(os.Stdin).ReadBytes('\n')
 }
 
+// ReadLine shows prompt to stdout and read a line from stdin.
 func ReadLine(prompt string) string {
 	fmt.Print(prompt)
 	input, _ := bufio.NewReader(os.Stdin).ReadString('\n')

core/codec/aesecb.go

@@ -10,6 +10,7 @@ import (
 	"github.com/tal-tech/go-zero/core/logx"
 )
 
+// ErrPaddingSize indicates bad padding size.
 var ErrPaddingSize = errors.New("padding size error")
 
 type ecb struct {
@@ -26,6 +27,7 @@ func newECB(b cipher.Block) *ecb {
 
 type ecbEncrypter ecb
 
+// NewECBEncrypter returns an ECB encrypter.
 func NewECBEncrypter(b cipher.Block) cipher.BlockMode {
 	return (*ecbEncrypter)(newECB(b))
 }
@@ -52,6 +54,7 @@ func (x *ecbEncrypter) CryptBlocks(dst, src []byte) {
 
 type ecbDecrypter ecb
 
+// NewECBDecrypter returns an ECB decrypter.
 func NewECBDecrypter(b cipher.Block) cipher.BlockMode {
 	return (*ecbDecrypter)(newECB(b))
 }
@@ -78,6 +81,7 @@ func (x *ecbDecrypter) CryptBlocks(dst, src []byte) {
 	}
 }
 
+// EcbDecrypt decrypts src with the given key.
 func EcbDecrypt(key, src []byte) ([]byte, error) {
 	block, err := aes.NewCipher(key)
 	if err != nil {
@@ -92,6 +96,8 @@ func EcbDecrypt(key, src []byte) ([]byte, error) {
 	return pkcs5Unpadding(decrypted, decrypter.BlockSize())
 }
 
+// EcbDecryptBase64 decrypts base64 encoded src with the given base64 encoded key.
+// The returned string is also base64 encoded.
 func EcbDecryptBase64(key, src string) (string, error) {
 	keyBytes, err := getKeyBytes(key)
 	if err != nil {
@@ -111,6 +117,7 @@ func EcbDecryptBase64(key, src string) (string, error) {
 	return base64.StdEncoding.EncodeToString(decryptedBytes), nil
 }
 
+// EcbEncrypt encrypts src with the given key.
 func EcbEncrypt(key, src []byte) ([]byte, error) {
 	block, err := aes.NewCipher(key)
 	if err != nil {
@@ -126,6 +133,8 @@ func EcbEncrypt(key, src []byte) ([]byte, error) {
 	return crypted, nil
 }
 
+// EcbEncryptBase64 encrypts base64 encoded src with the given base64 encoded key.
+// The returned string is also base64 encoded.
 func EcbEncryptBase64(key, src string) (string, error) {
 	keyBytes, err := getKeyBytes(key)
 	if err != nil {
@@ -150,11 +159,12 @@ func getKeyBytes(key string) ([]byte, error) {
 		return []byte(key), nil
 	}
 
-	if keyBytes, err := base64.StdEncoding.DecodeString(key); err != nil {
+	keyBytes, err := base64.StdEncoding.DecodeString(key)
+	if err != nil {
 		return nil, err
-	} else {
-		return keyBytes, nil
 	}
+
+	return keyBytes, nil
 }
 
 func pkcs5Padding(ciphertext []byte, blockSize int) []byte {

core/codec/aesecb_test.go

@@ -58,6 +58,7 @@ func TestAesEcbBase64(t *testing.T) {
 	_, err = EcbDecryptBase64(b64Key, val)
 	assert.NotNil(t, err)
 	src, err := EcbDecryptBase64(b64Key, dst)
+	assert.Nil(t, err)
 	b, err := base64.StdEncoding.DecodeString(src)
 	assert.Nil(t, err)
 	assert.Equal(t, val, string(b))

core/codec/dh.go

@@ -11,8 +11,11 @@ import (
 // 2048-bit MODP Group
 
 var (
+	// ErrInvalidPriKey indicates the invalid private key.
 	ErrInvalidPriKey = errors.New("invalid private key")
+	// ErrInvalidPubKey indicates the invalid public key.
 	ErrInvalidPubKey = errors.New("invalid public key")
+	// ErrPubKeyOutOfBound indicates the public key is out of bound.
 	ErrPubKeyOutOfBound = errors.New("public key out of bound")
 
 	p, _ = new(big.Int).SetString("FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD129024E088A67CC74020BBEA63B139B22514A08798E3404DDEF9519B3CD3A431B302B0A6DF25F14374FE1356D6D51C245E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7EDEE386BFB5A899FA5AE9F24117C4B1FE649286651ECE45B3DC2007CB8A163BF0598DA48361C55D39A69163FA8FD24CF5F83655D23DCA3AD961C62F356208552BB9ED529077096966D670C354E4ABC9804F1746C08CA18217C32905E462E36CE3BE39E772C180E86039B2783A2EC07A28FB5C55DF06F4C52C9DE2BCBF6955817183995497CEA956AE515D2261898FA051015728E5A8AACAA68FFFFFFFFFFFFFFFF", 16)
@@ -20,11 +23,13 @@ var (
 	zero = big.NewInt(0)
 )
 
+// DhKey defines the Diffie Hellman key.
 type DhKey struct {
 	PriKey *big.Int
 	PubKey *big.Int
 }
 
+// ComputeKey returns a key from public key and private key.
 func ComputeKey(pubKey, priKey *big.Int) (*big.Int, error) {
 	if pubKey == nil {
 		return nil, ErrInvalidPubKey
@@ -41,6 +46,7 @@ func ComputeKey(pubKey, priKey *big.Int) (*big.Int, error) {
 	return new(big.Int).Exp(pubKey, priKey, p), nil
 }
 
+// GenerateKey returns a Diffie Hellman key.
 func GenerateKey() (*DhKey, error) {
 	var err error
 	var x *big.Int
@@ -63,10 +69,12 @@ func GenerateKey() (*DhKey, error) {
 	return key, nil
 }
 
+// NewPublicKey returns a public key from the given bytes.
 func NewPublicKey(bs []byte) *big.Int {
 	return new(big.Int).SetBytes(bs)
 }
 
+// Bytes returns public key bytes.
 func (k *DhKey) Bytes() []byte {
 	if k.PubKey == nil {
 		return nil

core/codec/gzip.go

@@ -8,6 +8,7 @@ import (
 
 const unzipLimit = 100 * 1024 * 1024 // 100MB
 
+// Gzip compresses bs.
 func Gzip(bs []byte) []byte {
 	var b bytes.Buffer
 
@@ -18,6 +19,7 @@ func Gzip(bs []byte) []byte {
 	return b.Bytes()
 }
 
+// Gunzip uncompresses bs.
 func Gunzip(bs []byte) ([]byte, error) {
 	r, err := gzip.NewReader(bytes.NewBuffer(bs))
 	if err != nil {

core/codec/hmac.go

@@ -7,12 +7,14 @@ import (
 	"io"
 )
 
+// Hmac returns HMAC bytes for body with the given key.
 func Hmac(key []byte, body string) []byte {
 	h := hmac.New(sha256.New, key)
 	io.WriteString(h, body)
 	return h.Sum(nil)
 }
 
+// HmacBase64 returns the base64 encoded string of HMAC for body with the given key.
 func HmacBase64(key []byte, body string) string {
 	return base64.StdEncoding.EncodeToString(Hmac(key, body))
 }

core/codec/rsa.go

@@ -11,17 +11,22 @@ import (
 )
 
 var (
+	// ErrPrivateKey indicates the invalid private key.
 	ErrPrivateKey = errors.New("private key error")
+	// ErrPublicKey indicates the invalid public key.
 	ErrPublicKey = errors.New("failed to parse PEM block containing the public key")
+	// ErrNotRsaKey indicates the invalid RSA key.
 	ErrNotRsaKey = errors.New("key type is not RSA")
 )
 
 type (
+	// RsaDecrypter represents a RSA decrypter.
 	RsaDecrypter interface {
 		Decrypt(input []byte) ([]byte, error)
 		DecryptBase64(input string) ([]byte, error)
 	}
 
+	// RsaEncrypter represents a RSA encrypter.
 	RsaEncrypter interface {
 		Encrypt(input []byte) ([]byte, error)
 	}
@@ -41,6 +46,7 @@ type (
 	}
 )
 
+// NewRsaDecrypter returns a RsaDecrypter with the given file.
 func NewRsaDecrypter(file string) (RsaDecrypter, error) {
 	content, err := ioutil.ReadFile(file)
 	if err != nil {
@@ -84,6 +90,7 @@ func (r *rsaDecrypter) DecryptBase64(input string) ([]byte, error) {
 	return r.Decrypt(base64Decoded)
 }
 
+// NewRsaEncrypter returns a RsaEncrypter with the given key.
 func NewRsaEncrypter(key []byte) (RsaEncrypter, error) {
 	block, _ := pem.Decode(key)
 	if block == nil {

core/collection/cache.go

@@ -23,8 +23,10 @@ const (
 var emptyLruCache = emptyLru{}
 
 type (
+	// CacheOption defines the method to customize a Cache.
 	CacheOption func(cache *Cache)
 
+	// A Cache object is a in-memory cache.
 	Cache struct {
 		name           string
 		lock           sync.Mutex
@@ -38,6 +40,7 @@ type (
 	}
 )
 
+// NewCache returns a Cache with given expire.
 func NewCache(expire time.Duration, opts ...CacheOption) (*Cache, error) {
 	cache := &Cache{
 		data:           make(map[string]interface{}),
@@ -72,6 +75,7 @@ func NewCache(expire time.Duration, opts ...CacheOption) (*Cache, error) {
 	return cache, nil
 }
 
+// Del deletes the item with the given key from c.
 func (c *Cache) Del(key string) {
 	c.lock.Lock()
 	delete(c.data, key)
@@ -80,6 +84,7 @@ func (c *Cache) Del(key string) {
 	c.timingWheel.RemoveTimer(key)
 }
 
+// Get returns the item with the given key from c.
 func (c *Cache) Get(key string) (interface{}, bool) {
 	value, ok := c.doGet(key)
 	if ok {
@@ -91,6 +96,7 @@ func (c *Cache) Get(key string) (interface{}, bool) {
 	return value, ok
 }
 
+// Set sets value into c with key.
 func (c *Cache) Set(key string, value interface{}) {
 	c.lock.Lock()
 	_, ok := c.data[key]
@@ -106,6 +112,9 @@ func (c *Cache) Set(key string, value interface{}) {
 	}
 }
 
+// Take returns the item with the given key.
+// If the item is in c, return it directly.
+// If not, use fetch method to get the item, set into c and return it.
 func (c *Cache) Take(key string, fetch func() (interface{}, error)) (interface{}, error) {
 	if val, ok := c.doGet(key); ok {
 		c.stats.IncrementHit()
@@ -136,11 +145,10 @@ func (c *Cache) Take(key string, fetch func() (interface{}, error)) (interface{}
 	if fresh {
 		c.stats.IncrementMiss()
 		return val, nil
-	} else {
-		// got the result from previous ongoing query
-		c.stats.IncrementHit()
 	}
 
+	// got the result from previous ongoing query
+	c.stats.IncrementHit()
 	return val, nil
 }
 
@@ -168,6 +176,7 @@ func (c *Cache) size() int {
 	return len(c.data)
 }
 
+// WithLimit customizes a Cache with items up to limit.
 func WithLimit(limit int) CacheOption {
 	return func(cache *Cache) {
 		if limit > 0 {
@@ -176,6 +185,7 @@ func WithLimit(limit int) CacheOption {
 	}
 }
 
+// WithName customizes a Cache with the given name.
 func WithName(name string) CacheOption {
 	return func(cache *Cache) {
 		cache.name = name

core/collection/fifo.go

@@ -2,6 +2,7 @@ package collection
 
 import "sync"
 
+// A Queue is a FIFO queue.
 type Queue struct {
 	lock     sync.Mutex
 	elements []interface{}
@@ -11,6 +12,7 @@ type Queue struct {
 	count    int
 }
 
+// NewQueue returns a Queue object.
 func NewQueue(size int) *Queue {
 	return &Queue{
 		elements: make([]interface{}, size),
@@ -18,6 +20,7 @@ func NewQueue(size int) *Queue {
 	}
 }
 
+// Empty checks if q is empty.
 func (q *Queue) Empty() bool {
 	q.lock.Lock()
 	empty := q.count == 0
@@ -26,6 +29,7 @@ func (q *Queue) Empty() bool {
 	return empty
 }
 
+// Put puts element into q at the last position.
 func (q *Queue) Put(element interface{}) {
 	q.lock.Lock()
 	defer q.lock.Unlock()
@@ -44,6 +48,7 @@ func (q *Queue) Put(element interface{}) {
 	q.count++
 }
 
+// Take takes the first element out of q if not empty.
 func (q *Queue) Take() (interface{}, bool) {
 	q.lock.Lock()
 	defer q.lock.Unlock()

core/collection/ring.go

@@ -1,10 +1,15 @@
 package collection
 
+import "sync"
+
+// A Ring can be used as fixed size ring.
 type Ring struct {
 	elements []interface{}
 	index    int
+	lock     sync.Mutex
 }
 
+// NewRing returns a Ring object with the given size n.
 func NewRing(n int) *Ring {
 	if n < 1 {
 		panic("n should be greater than 0")
@@ -15,12 +20,20 @@ func NewRing(n int) *Ring {
 	}
 }
 
+// Add adds v into r.
 func (r *Ring) Add(v interface{}) {
+	r.lock.Lock()
+	defer r.lock.Unlock()
+
 	r.elements[r.index%len(r.elements)] = v
 	r.index++
 }
 
+// Take takes all items from r.
 func (r *Ring) Take() []interface{} {
+	r.lock.Lock()
+	defer r.lock.Unlock()
+
 	var size int
 	var start int
 	if r.index > len(r.elements) {

core/collection/ring_test.go

@@ -1,6 +1,7 @@
 package collection
 
 import (
+	"sync"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -29,3 +30,30 @@ func TestRingMore(t *testing.T) {
 	elements := ring.Take()
 	assert.ElementsMatch(t, []interface{}{6, 7, 8, 9, 10}, elements)
 }
+
+func TestRingAdd(t *testing.T) {
+	ring := NewRing(5051)
+	wg := sync.WaitGroup{}
+	for i := 1; i <= 100; i++ {
+		wg.Add(1)
+		go func(i int) {
+			defer wg.Done()
+			for j := 1; j <= i; j++ {
+				ring.Add(i)
+			}
+		}(i)
+	}
+	wg.Wait()
+	assert.Equal(t, 5050, len(ring.Take()))
+}
+
+func BenchmarkRingAdd(b *testing.B) {
+	ring := NewRing(500)
+	b.RunParallel(func(pb *testing.PB) {
+		for pb.Next() {
+			for i := 0; i < b.N; i++ {
+				ring.Add(i)
+			}
+		}
+	})
+}

core/collection/rollingwindow.go

@@ -73,9 +73,9 @@ func (rw *RollingWindow) span() int {
 	offset := int(timex.Since(rw.lastTime) / rw.interval)
 	if 0 <= offset && offset < rw.size {
 		return offset
-	} else {
-		return rw.size
 	}
+
+	return rw.size
 }
 
 func (rw *RollingWindow) updateOffset() {

core/collection/safemap.go

@@ -18,6 +18,7 @@ type SafeMap struct {
 	dirtyNew    map[interface{}]interface{}
 }
 
+// NewSafeMap returns a SafeMap.
 func NewSafeMap() *SafeMap {
 	return &SafeMap{
 		dirtyOld: make(map[interface{}]interface{}),
@@ -25,6 +26,7 @@ func NewSafeMap() *SafeMap {
 	}
 }
 
+// Del deletes the value with the given key from m.
 func (m *SafeMap) Del(key interface{}) {
 	m.lock.Lock()
 	if _, ok := m.dirtyOld[key]; ok {
@@ -53,18 +55,20 @@ func (m *SafeMap) Del(key interface{}) {
 	m.lock.Unlock()
 }
 
+// Get gets the value with the given key from m.
 func (m *SafeMap) Get(key interface{}) (interface{}, bool) {
 	m.lock.RLock()
 	defer m.lock.RUnlock()
 
 	if val, ok := m.dirtyOld[key]; ok {
 		return val, true
-	} else {
+	}
+
 	val, ok := m.dirtyNew[key]
 	return val, ok
-	}
 }
 
+// Set sets the value into m with the given key.
 func (m *SafeMap) Set(key, value interface{}) {
 	m.lock.Lock()
 	if m.deletionOld <= maxDeletion {
@@ -83,6 +87,7 @@ func (m *SafeMap) Set(key, value interface{}) {
 	m.lock.Unlock()
 }
 
+// Size returns the size of m.
 func (m *SafeMap) Size() int {
 	m.lock.RLock()
 	size := len(m.dirtyOld) + len(m.dirtyNew)

core/collection/set.go

@@ -21,6 +21,7 @@ type Set struct {
 	tp   int
 }
 
+// NewSet returns a managed Set, can only put the values with the same type.
 func NewSet() *Set {
 	return &Set{
 		data: make(map[interface{}]lang.PlaceholderType),
@@ -28,6 +29,7 @@ func NewSet() *Set {
 	}
 }
 
+// NewUnmanagedSet returns a unmanaged Set, which can put values with different types.
 func NewUnmanagedSet() *Set {
 	return &Set{
 		data: make(map[interface{}]lang.PlaceholderType),
@@ -35,42 +37,49 @@ func NewUnmanagedSet() *Set {
 	}
 }
 
+// Add adds i into s.
 func (s *Set) Add(i ...interface{}) {
 	for _, each := range i {
 		s.add(each)
 	}
 }
 
+// AddInt adds int values ii into s.
 func (s *Set) AddInt(ii ...int) {
 	for _, each := range ii {
 		s.add(each)
 	}
 }
 
+// AddInt64 adds int64 values ii into s.
 func (s *Set) AddInt64(ii ...int64) {
 	for _, each := range ii {
 		s.add(each)
 	}
 }
 
+// AddUint adds uint values ii into s.
 func (s *Set) AddUint(ii ...uint) {
 	for _, each := range ii {
 		s.add(each)
 	}
 }
 
+// AddUint64 adds uint64 values ii into s.
 func (s *Set) AddUint64(ii ...uint64) {
 	for _, each := range ii {
 		s.add(each)
 	}
 }
 
+// AddStr adds string values ss into s.
 func (s *Set) AddStr(ss ...string) {
 	for _, each := range ss {
 		s.add(each)
 	}
 }
 
+// Contains checks if i is in s.
 func (s *Set) Contains(i interface{}) bool {
 	if len(s.data) == 0 {
 		return false
@@ -81,6 +90,7 @@ func (s *Set) Contains(i interface{}) bool {
 	return ok
 }
 
+// Keys returns the keys in s.
 func (s *Set) Keys() []interface{} {
 	var keys []interface{}
 
@@ -91,6 +101,7 @@ func (s *Set) Keys() []interface{} {
 	return keys
 }
 
+// KeysInt returns the int keys in s.
 func (s *Set) KeysInt() []int {
 	var keys []int
 
@@ -105,6 +116,7 @@ func (s *Set) KeysInt() []int {
 	return keys
 }
 
+// KeysInt64 returns int64 keys in s.
 func (s *Set) KeysInt64() []int64 {
 	var keys []int64
 
@@ -119,6 +131,7 @@ func (s *Set) KeysInt64() []int64 {
 	return keys
 }
 
+// KeysUint returns uint keys in s.
 func (s *Set) KeysUint() []uint {
 	var keys []uint
 
@@ -133,6 +146,7 @@ func (s *Set) KeysUint() []uint {
 	return keys
 }
 
+// KeysUint64 returns uint64 keys in s.
 func (s *Set) KeysUint64() []uint64 {
 	var keys []uint64
 
@@ -147,6 +161,7 @@ func (s *Set) KeysUint64() []uint64 {
 	return keys
 }
 
+// KeysStr returns string keys in s.
 func (s *Set) KeysStr() []string {
 	var keys []string
 
@@ -161,11 +176,13 @@ func (s *Set) KeysStr() []string {
 	return keys
 }
 
+// Remove removes i from s.
 func (s *Set) Remove(i interface{}) {
 	s.validate(i)
 	delete(s.data, i)
 }
 
+// Count returns the number of items in s.
 func (s *Set) Count() int {
 	return len(s.data)
 }

core/collection/timingwheel.go

@@ -13,8 +13,10 @@ import (
 const drainWorkers = 8
 
 type (
+	// Execute defines the method to execute the task.
 	Execute func(key, value interface{})
 
+	// A TimingWheel is a timing wheel object to schedule tasks.
 	TimingWheel struct {
 		interval      time.Duration
 		ticker        timex.Ticker
@@ -54,6 +56,7 @@ type (
 	}
 )
 
+// NewTimingWheel returns a TimingWheel.
 func NewTimingWheel(interval time.Duration, numSlots int, execute Execute) (*TimingWheel, error) {
 	if interval <= 0 || numSlots <= 0 || execute == nil {
 		return nil, fmt.Errorf("interval: %v, slots: %d, execute: %p", interval, numSlots, execute)
@@ -85,10 +88,12 @@ func newTimingWheelWithClock(interval time.Duration, numSlots int, execute Execu
 	return tw, nil
 }
 
+// Drain drains all items and executes them.
 func (tw *TimingWheel) Drain(fn func(key, value interface{})) {
 	tw.drainChannel <- fn
 }
 
+// MoveTimer moves the task with the given key to the given delay.
 func (tw *TimingWheel) MoveTimer(key interface{}, delay time.Duration) {
 	if delay <= 0 || key == nil {
 		return
@@ -100,6 +105,7 @@ func (tw *TimingWheel) MoveTimer(key interface{}, delay time.Duration) {
 	}
 }
 
+// RemoveTimer removes the task with the given key.
 func (tw *TimingWheel) RemoveTimer(key interface{}) {
 	if key == nil {
 		return
@@ -108,6 +114,7 @@ func (tw *TimingWheel) RemoveTimer(key interface{}) {
 	tw.removeChannel <- key
 }
 
+// SetTimer sets the task value with the given key to the delay.
 func (tw *TimingWheel) SetTimer(key, value interface{}, delay time.Duration) {
 	if delay <= 0 || key == nil {
 		return
@@ -122,6 +129,7 @@ func (tw *TimingWheel) SetTimer(key, value interface{}, delay time.Duration) {
 	}
 }
 
+// Stop stops tw.
 func (tw *TimingWheel) Stop() {
 	close(tw.stopChannel)
 }

core/conf/config.go

@@ -16,26 +16,43 @@ var loaders = map[string]func([]byte, interface{}) error{
 	".yml":  LoadConfigFromYamlBytes,
 }
 
-func LoadConfig(file string, v interface{}) error {
-	if content, err := ioutil.ReadFile(file); err != nil {
+// LoadConfig loads config into v from file, .json, .yaml and .yml are acceptable.
+func LoadConfig(file string, v interface{}, opts ...Option) error {
+	content, err := ioutil.ReadFile(file)
+	if err != nil {
 		return err
-	} else if loader, ok := loaders[path.Ext(file)]; ok {
-		return loader([]byte(os.ExpandEnv(string(content))), v)
-	} else {
+	}
+
+	loader, ok := loaders[path.Ext(file)]
+	if !ok {
 		return fmt.Errorf("unrecoginized file type: %s", file)
 	}
+
+	var opt options
+	for _, o := range opts {
+		o(&opt)
+	}
+
+	if opt.env {
+		return loader([]byte(os.ExpandEnv(string(content))), v)
+	}
+
+	return loader(content, v)
 }
 
+// LoadConfigFromJsonBytes loads config into v from content json bytes.
 func LoadConfigFromJsonBytes(content []byte, v interface{}) error {
 	return mapping.UnmarshalJsonBytes(content, v)
 }
 
+// LoadConfigFromYamlBytes loads config into v from content yaml bytes.
 func LoadConfigFromYamlBytes(content []byte, v interface{}) error {
 	return mapping.UnmarshalYamlBytes(content, v)
 }
 
-func MustLoad(path string, v interface{}) {
-	if err := LoadConfig(path, v); err != nil {
+// MustLoad loads config into v from path, exits on error.
+func MustLoad(path string, v interface{}, opts ...Option) {
+	if err := LoadConfig(path, v, opts...); err != nil {
 		log.Fatalf("error: config file %s, %s", path, err.Error())
 	}
 }

core/conf/config_test.go

@@ -30,7 +30,8 @@ func TestConfigJson(t *testing.T) {
 	text := `{
 	"a": "foo",
 	"b": 1,
-	"c": "${FOO}"
+	"c": "${FOO}",
+	"d": "abcd!@#$112"
 }`
 	for _, test := range tests {
 		test := test
@@ -45,11 +46,49 @@ func TestConfigJson(t *testing.T) {
 				A string `json:"a"`
 				B int    `json:"b"`
 				C string `json:"c"`
+				D string `json:"d"`
 			}
 			MustLoad(tmpfile, &val)
 			assert.Equal(t, "foo", val.A)
 			assert.Equal(t, 1, val.B)
+			assert.Equal(t, "${FOO}", val.C)
+			assert.Equal(t, "abcd!@#$112", val.D)
+		})
+	}
+}
+
+func TestConfigJsonEnv(t *testing.T) {
+	tests := []string{
+		".json",
+		".yaml",
+		".yml",
+	}
+	text := `{
+	"a": "foo",
+	"b": 1,
+	"c": "${FOO}",
+	"d": "abcd!@#$a12 3"
+}`
+	for _, test := range tests {
+		test := test
+		t.Run(test, func(t *testing.T) {
+			os.Setenv("FOO", "2")
+			defer os.Unsetenv("FOO")
+			tmpfile, err := createTempFile(test, text)
+			assert.Nil(t, err)
+			defer os.Remove(tmpfile)
+
+			var val struct {
+				A string `json:"a"`
+				B int    `json:"b"`
+				C string `json:"c"`
+				D string `json:"d"`
+			}
+			MustLoad(tmpfile, &val, UseEnv())
+			assert.Equal(t, "foo", val.A)
+			assert.Equal(t, 1, val.B)
 			assert.Equal(t, "2", val.C)
+			assert.Equal(t, "abcd!@# 3", val.D)
 		})
 	}
 }

core/conf/options.go

@@ -0,0 +1,17 @@
+package conf
+
+type (
+	// Option defines the method to customize the config options.
+	Option func(opt *options)
+
+	options struct {
+		env bool
+	}
+)
+
+// UseEnv customizes the config to use environment variables.
+func UseEnv() Option {
+	return func(opt *options) {
+		opt.env = true
+	}
+}

core/conf/properties.go

@@ -2,6 +2,7 @@ package conf
 
 import (
 	"fmt"
+	"os"
 	"strconv"
 	"strings"
 	"sync"
@@ -30,14 +31,19 @@ type mapBasedProperties struct {
 	lock       sync.RWMutex
 }
 
-// Loads the properties into a properties configuration instance.
+// LoadProperties loads the properties into a properties configuration instance.
 // Returns an error that indicates if there was a problem loading the configuration.
-func LoadProperties(filename string) (Properties, error) {
+func LoadProperties(filename string, opts ...Option) (Properties, error) {
 	lines, err := iox.ReadTextLines(filename, iox.WithoutBlank(), iox.OmitWithPrefix("#"))
 	if err != nil {
 		return nil, err
 	}
 
+	var opt options
+	for _, o := range opts {
+		o(&opt)
+	}
+
 	raw := make(map[string]string)
 	for i := range lines {
 		pair := strings.Split(lines[i], "=")
@@ -50,8 +56,12 @@ func LoadProperties(filename string) (Properties, error) {
 
 		key := strings.TrimSpace(pair[0])
 		value := strings.TrimSpace(pair[1])
+		if opt.env {
+			raw[key] = os.ExpandEnv(value)
+		} else {
 			raw[key] = value
 		}
+	}
 
 	return &mapBasedProperties{
 		properties: raw,
@@ -87,7 +97,7 @@ func (config *mapBasedProperties) SetInt(key string, value int) {
 	config.lock.Unlock()
 }
 
-// Dumps the configuration internal map into a string.
+// ToString dumps the configuration internal map into a string.
 func (config *mapBasedProperties) ToString() string {
 	config.lock.RLock()
 	ret := fmt.Sprintf("%s", config.properties)
@@ -96,12 +106,12 @@ func (config *mapBasedProperties) ToString() string {
 	return ret
 }
 
-// Returns the error message.
+// Error returns the error message.
 func (configError *PropertyError) Error() string {
 	return configError.message
 }
 
-// Builds a new properties configuration structure
+// NewProperties builds a new properties configuration structure.
 func NewProperties() Properties {
 	return &mapBasedProperties{
 		properties: make(map[string]string),

core/conf/properties_test.go

@@ -31,6 +31,39 @@ func TestProperties(t *testing.T) {
 	assert.Contains(t, val, "app.threads")
 }
 
+func TestPropertiesEnv(t *testing.T) {
+	text := `app.name = test
+
+    app.program=app
+
+	app.env1 = ${FOO}
+	app.env2 = $none
+
+    # this is comment
+    app.threads = 5`
+	tmpfile, err := fs.TempFilenameWithText(text)
+	assert.Nil(t, err)
+	defer os.Remove(tmpfile)
+
+	os.Setenv("FOO", "2")
+	defer os.Unsetenv("FOO")
+
+	props, err := LoadProperties(tmpfile, UseEnv())
+	assert.Nil(t, err)
+	assert.Equal(t, "test", props.GetString("app.name"))
+	assert.Equal(t, "app", props.GetString("app.program"))
+	assert.Equal(t, 5, props.GetInt("app.threads"))
+	assert.Equal(t, "2", props.GetString("app.env1"))
+	assert.Equal(t, "", props.GetString("app.env2"))
+
+	val := props.ToString()
+	assert.Contains(t, val, "app.name")
+	assert.Contains(t, val, "app.program")
+	assert.Contains(t, val, "app.threads")
+	assert.Contains(t, val, "app.env1")
+	assert.Contains(t, val, "app.env2")
+}
+
 func TestLoadProperties_badContent(t *testing.T) {
 	filename, err := fs.TempFilenameWithText("hello")
 	assert.Nil(t, err)

core/contextx/deadline.go

@@ -5,6 +5,8 @@ import (
 	"time"
 )
 
+// ShrinkDeadline returns a new Context with proper deadline base on the given ctx and timeout.
+// And returns a cancel function as well.
 func ShrinkDeadline(ctx context.Context, timeout time.Duration) (context.Context, func()) {
 	if deadline, ok := ctx.Deadline(); ok {
 		leftTime := time.Until(deadline)

core/contextx/unmarshaler.go

@@ -19,6 +19,7 @@ func (cv contextValuer) Value(key string) (interface{}, bool) {
 	return v, v != nil
 }
 
+// For unmarshals ctx into v.
 func For(ctx context.Context, v interface{}) error {
 	return unmarshaler.UnmarshalValuer(contextValuer{
 		Context: ctx,

core/contextx/valueonlycontext.go

@@ -21,6 +21,7 @@ func (valueOnlyContext) Err() error {
 	return nil
 }
 
+// ValueOnlyFrom takes all values from the given ctx, without deadline and error control.
 func ValueOnlyFrom(ctx context.Context) context.Context {
 	return valueOnlyContext{
 		Context: ctx,

core/discov/clients.go

@@ -14,6 +14,7 @@ const (
 
 const timeToLive int64 = 10
 
+// TimeToLive is seconds to live in etcd.
 var TimeToLive = timeToLive
 
 func extract(etcdKey string, index int) (string, bool) {

core/discov/clients_test.go

@@ -28,6 +28,9 @@ func TestExtract(t *testing.T) {
 
 	_, ok = extract("any", -1)
 	assert.False(t, ok)
+
+	_, ok = extract("any", 10)
+	assert.False(t, ok)
 }
 
 func TestMakeKey(t *testing.T) {

core/discov/config.go

@@ -2,11 +2,13 @@ package discov
 
 import "errors"
 
+// EtcdConf is the config item with the given key on etcd.
 type EtcdConf struct {
 	Hosts []string
 	Key   string
 }
 
+// Validate validates c.
 func (c EtcdConf) Validate() error {
 	if len(c.Hosts) == 0 {
 		return errors.New("empty etcd hosts")

core/discov/facade.go

@@ -1,47 +0,0 @@
-package discov
-
-import (
-	"github.com/tal-tech/go-zero/core/discov/internal"
-	"github.com/tal-tech/go-zero/core/logx"
-)
-
-type (
-	Facade struct {
-		endpoints []string
-		registry  *internal.Registry
-	}
-
-	FacadeListener interface {
-		OnAdd(key, val string)
-		OnDelete(key string)
-	}
-)
-
-func NewFacade(endpoints []string) Facade {
-	return Facade{
-		endpoints: endpoints,
-		registry:  internal.GetRegistry(),
-	}
-}
-
-func (f Facade) Client() internal.EtcdClient {
-	conn, err := f.registry.GetConn(f.endpoints)
-	logx.Must(err)
-	return conn
-}
-
-func (f Facade) Monitor(key string, l FacadeListener) {
-	f.registry.Monitor(f.endpoints, key, listenerAdapter{l})
-}
-
-type listenerAdapter struct {
-	l FacadeListener
-}
-
-func (la listenerAdapter) OnAdd(kv internal.KV) {
-	la.l.OnAdd(kv.Key, kv.Val)
-}
-
-func (la listenerAdapter) OnDelete(kv internal.KV) {
-	la.l.OnDelete(kv.Key)
-}

core/discov/internal/etcdclient.go

@@ -1,4 +1,5 @@
 //go:generate mockgen -package internal -destination etcdclient_mock.go -source etcdclient.go EtcdClient
+
 package internal
 
 import (
@@ -8,6 +9,7 @@ import (
 	"google.golang.org/grpc"
 )
 
+// EtcdClient interface represents an etcd client.
 type EtcdClient interface {
 	ActiveConnection() *grpc.ClientConn
 	Close() error

core/discov/internal/listener.go

@@ -1,5 +1,6 @@
 package internal
 
+// Listener interface wraps the OnUpdate method.
 type Listener interface {
 	OnUpdate(keys []string, values []string, newKey string)
 }

core/discov/internal/registry.go

@@ -18,19 +18,31 @@ import (
 )
 
 var (
-	registryInstance = Registry{
+	registry = Registry{
 		clusters: make(map[string]*cluster),
 	}
 	connManager = syncx.NewResourceManager()
 )
 
+// A Registry is a registry that manages the etcd client connections.
 type Registry struct {
 	clusters map[string]*cluster
 	lock     sync.Mutex
 }
 
+// GetRegistry returns a global Registry.
 func GetRegistry() *Registry {
-	return &registryInstance
+	return &registry
+}
+
+// GetConn returns an etcd client connection associated with given endpoints.
+func (r *Registry) GetConn(endpoints []string) (EtcdClient, error) {
+	return r.getCluster(endpoints).getClient()
+}
+
+// Monitor monitors the key on given etcd endpoints, notify with the given UpdateListener.
+func (r *Registry) Monitor(endpoints []string, key string, l UpdateListener) error {
+	return r.getCluster(endpoints).monitor(key, l)
 }
 
 func (r *Registry) getCluster(endpoints []string) *cluster {
@@ -46,14 +58,6 @@ func (r *Registry) getCluster(endpoints []string) *cluster {
 	return c
 }
 
-func (r *Registry) GetConn(endpoints []string) (EtcdClient, error) {
-	return r.getCluster(endpoints).getClient()
-}
-
-func (r *Registry) Monitor(endpoints []string, key string, l UpdateListener) error {
-	return r.getCluster(endpoints).monitor(key, l)
-}
-
 type cluster struct {
 	endpoints  []string
 	key        string
@@ -288,6 +292,7 @@ func (c *cluster) watchConnState(cli EtcdClient) {
 	watcher.watch(cli.ActiveConnection())
 }
 
+// DialClient dials an etcd cluster with given endpoints.
 func DialClient(endpoints []string) (EtcdClient, error) {
 	return clientv3.New(clientv3.Config{
 		Endpoints:            endpoints,

core/discov/internal/statewatcher.go

@@ -1,4 +1,5 @@
 //go:generate mockgen -package internal -destination statewatcher_mock.go -source statewatcher.go etcdConn
+
 package internal
 
 import (

core/discov/internal/updatelistener.go

@@ -1,12 +1,15 @@
 //go:generate mockgen -package internal -destination updatelistener_mock.go -source updatelistener.go UpdateListener
+
 package internal
 
 type (
+	// A KV is used to store an etcd entry with key and value.
 	KV struct {
 		Key string
 		Val string
 	}
 
+	// UpdateListener wraps the OnAdd and OnDelete methods.
 	UpdateListener interface {
 		OnAdd(kv KV)
 		OnDelete(kv KV)

core/discov/internal/vars.go

@@ -3,17 +3,22 @@ package internal
 import "time"
 
 const (
+	// Delimiter is a separator that separates the etcd path.
+	Delimiter = '/'
+
 	autoSyncInterval   = time.Minute
 	coolDownInterval   = time.Second
 	dialTimeout        = 5 * time.Second
 	dialKeepAliveTime  = 5 * time.Second
 	requestTimeout     = 3 * time.Second
-	Delimiter          = '/'
 	endpointsSeparator = ","
 )
 
 var (
+	// DialTimeout is the dial timeout.
 	DialTimeout = dialTimeout
+	// RequestTimeout is the request timeout.
 	RequestTimeout = requestTimeout
+	// NewClient is used to create etcd clients.
 	NewClient = DialClient
 )

core/discov/kubernetes/etcd-statefulset.yaml

@@ -0,0 +1,64 @@
+apiVersion: apps/v1
+kind: StatefulSet
+metadata:
+  name: "etcd"
+  namespace: discov
+  labels:
+    app: "etcd"
+spec:
+  serviceName: "etcd"
+  replicas: 5
+  template:
+    metadata:
+      name: "etcd"
+      labels:
+        app: "etcd"
+    spec:
+      volumes:
+      - name: etcd-pvc
+        persistentVolumeClaim:
+          claimName: etcd-pvc
+      containers:
+      - name: "etcd"
+        image: quay.io/coreos/etcd:latest
+        ports:
+        - containerPort: 2379
+          name: client
+        - containerPort: 2380
+          name: peer
+        env:
+        - name: CLUSTER_SIZE
+          value: "5"
+        - name: SET_NAME
+          value: "etcd"
+        - name: VOLNAME
+          valueFrom:
+            fieldRef:
+              apiVersion: v1
+              fieldPath: metadata.name
+        volumeMounts:
+        - name: etcd-pvc
+          mountPath: /var/lib/etcd
+          subPathExpr: $(VOLNAME)  # data mounted respectively in each pod
+        command:
+          - "/bin/sh"
+          - "-ecx"
+          - |
+
+            chmod 700 /var/lib/etcd
+
+            IP=$(hostname -i)
+            PEERS=""
+            for i in $(seq 0 $((${CLUSTER_SIZE} - 1))); do
+                PEERS="${PEERS}${PEERS:+,}${SET_NAME}-${i}=http://${SET_NAME}-${i}.${SET_NAME}:2380"
+            done
+            exec etcd --name ${HOSTNAME} \
+              --listen-peer-urls http://0.0.0.0:2380 \
+              --listen-client-urls http://0.0.0.0:2379 \
+              --advertise-client-urls http://${HOSTNAME}.${SET_NAME}.discov:2379 \
+              --initial-advertise-peer-urls http://${HOSTNAME}.${SET_NAME}:2380 \
+              --initial-cluster ${PEERS} \
+              --initial-cluster-state new \
+              --logger zap \
+              --data-dir /var/lib/etcd \
+              --auto-compaction-retention 1

core/discov/publisher.go

@@ -11,8 +11,10 @@ import (
 )
 
 type (
+	// PublisherOption defines the method to customize a Publisher.
 	PublisherOption func(client *Publisher)
 
+	// A Publisher can be used to publish the value to an etcd cluster on the given key.
 	Publisher struct {
 		endpoints  []string
 		key        string
@@ -26,6 +28,10 @@ type (
 	}
 )
 
+// NewPublisher returns a Publisher.
+// endpoints is the hosts of the etcd cluster.
+// key:value are a pair to be published.
+// opts are used to customize the Publisher.
 func NewPublisher(endpoints []string, key, value string, opts ...PublisherOption) *Publisher {
 	publisher := &Publisher{
 		endpoints:  endpoints,
@@ -43,6 +49,7 @@ func NewPublisher(endpoints []string, key, value string, opts ...PublisherOption
 	return publisher
 }
 
+// KeepAlive keeps key:value alive.
 func (p *Publisher) KeepAlive() error {
 	cli, err := internal.GetRegistry().GetConn(p.endpoints)
 	if err != nil {
@@ -61,14 +68,17 @@ func (p *Publisher) KeepAlive() error {
 	return p.keepAliveAsync(cli)
 }
 
+// Pause pauses the renewing of key:value.
 func (p *Publisher) Pause() {
 	p.pauseChan <- lang.Placeholder
 }
 
+// Resume resumes the renewing of key:value.
 func (p *Publisher) Resume() {
 	p.resumeChan <- lang.Placeholder
 }
 
+// Stop stops the renewing and revokes the registration.
 func (p *Publisher) Stop() {
 	p.quit.Close()
 }
@@ -135,6 +145,7 @@ func (p *Publisher) revoke(cli internal.EtcdClient) {
 	}
 }
 
+// WithId customizes a Publisher with the id.
 func WithId(id int64) PublisherOption {
 	return func(publisher *Publisher) {
 		publisher.id = id

core/discov/publisher_test.go

@@ -4,10 +4,12 @@ import (
 	"errors"
 	"sync"
 	"testing"
+	"time"
 
 	"github.com/golang/mock/gomock"
 	"github.com/stretchr/testify/assert"
 	"github.com/tal-tech/go-zero/core/discov/internal"
+	"github.com/tal-tech/go-zero/core/lang"
 	"github.com/tal-tech/go-zero/core/logx"
 	"go.etcd.io/etcd/clientv3"
 )
@@ -152,3 +154,16 @@ func TestPublisher_keepAliveAsyncPause(t *testing.T) {
 	pub.Pause()
 	wg.Wait()
 }
+
+func TestPublisher_Resume(t *testing.T) {
+	publisher := new(Publisher)
+	publisher.resumeChan = make(chan lang.PlaceholderType)
+	go func() {
+		publisher.Resume()
+	}()
+	go func() {
+		time.Sleep(time.Minute)
+		t.Fail()
+	}()
+	<-publisher.resumeChan
+}

core/discov/subscriber.go

@@ -13,13 +13,19 @@ type (
 		exclusive bool
 	}
 
+	// SubOption defines the method to customize a Subscriber.
 	SubOption func(opts *subOptions)
 
+	// A Subscriber is used to subscribe the given key on a etcd cluster.
 	Subscriber struct {
 		items *container
 	}
 )
 
+// NewSubscriber returns a Subscriber.
+// endpoints is the hosts of the etcd cluster.
+// key is the key to subscribe.
+// opts are used to customize the Subscriber.
 func NewSubscriber(endpoints []string, key string, opts ...SubOption) (*Subscriber, error) {
 	var subOpts subOptions
 	for _, opt := range opts {
@@ -36,15 +42,17 @@ func NewSubscriber(endpoints []string, key string, opts ...SubOption) (*Subscrib
 	return sub, nil
 }
 
+// AddListener adds listener to s.
 func (s *Subscriber) AddListener(listener func()) {
 	s.items.addListener(listener)
 }
 
+// Values returns all the subscription values.
 func (s *Subscriber) Values() []string {
 	return s.items.getValues()
 }
 
-// exclusive means that key value can only be 1:1,
+// Exclusive means that key value can only be 1:1,
 // which means later added value will remove the keys associated with the same value previously.
 func Exclusive() SubOption {
 	return func(opts *subOptions) {
@@ -100,9 +108,9 @@ func (c *container) addKv(key, value string) ([]string, bool) {
 
 	if early {
 		return previous, true
-	} else {
-		return nil, false
 	}
+
+	return nil, false
 }
 
 func (c *container) addListener(listener func()) {

core/discov/subscriber_test.go

@@ -1,6 +1,7 @@
 package discov
 
 import (
+	"sync/atomic"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -198,3 +199,18 @@ func TestContainer(t *testing.T) {
 		}
 	}
 }
+
+func TestSubscriber(t *testing.T) {
+	var opt subOptions
+	Exclusive()(&opt)
+
+	sub := new(Subscriber)
+	sub.items = newContainer(opt.exclusive)
+	var count int32
+	sub.AddListener(func() {
+		atomic.AddInt32(&count, 1)
+	})
+	sub.items.notifyChange()
+	assert.Empty(t, sub.Values())
+	assert.Equal(t, int32(1), atomic.LoadInt32(&count))
+}

core/errorx/atomicerror.go

@@ -2,14 +2,17 @@ package errorx
 
 import "sync/atomic"
 
+// AtomicError defines an atomic error.
 type AtomicError struct {
 	err atomic.Value // error
 }
 
+// Set sets the error.
 func (ae *AtomicError) Set(err error) {
 	ae.err.Store(err)
 }
 
+// Load returns the error.
 func (ae *AtomicError) Load() error {
 	if v := ae.err.Load(); v != nil {
 		return v.(error)

core/errorx/batcherror.go

@@ -3,6 +3,7 @@ package errorx
 import "bytes"
 
 type (
+	// A BatchError is an error that can hold multiple errors.
 	BatchError struct {
 		errs errorArray
 	}
@@ -10,12 +11,14 @@ type (
 	errorArray []error
 )
 
+// Add adds err to be.
 func (be *BatchError) Add(err error) {
 	if err != nil {
 		be.errs = append(be.errs, err)
 	}
 }
 
+// Err returns an error that represents all errors.
 func (be *BatchError) Err() error {
 	switch len(be.errs) {
 	case 0:
@@ -27,10 +30,12 @@ func (be *BatchError) Err() error {
 	}
 }
 
+// NotNil checks if any error inside.
 func (be *BatchError) NotNil() bool {
 	return len(be.errs) > 0
 }
 
+// Error returns a string that represents inside errors.
 func (ea errorArray) Error() string {
 	var buf bytes.Buffer
 

core/errorx/callchain.go

@@ -1,5 +1,6 @@
 package errorx
 
+// Chain runs funs one by one until an error occurred.
 func Chain(fns ...func() error) error {
 	for _, fn := range fns {
 		if err := fn(); err != nil {

core/executors/bulkexecutor.go

@@ -5,8 +5,12 @@ import "time"
 const defaultBulkTasks = 1000
 
 type (
+	// BulkOption defines the method to customize a BulkExecutor.
 	BulkOption func(options *bulkOptions)
 
+	// A BulkExecutor is an executor that can execute tasks on either requirement meets:
+	// 1. up to given size of tasks
+	// 2. flush interval time elapsed
 	BulkExecutor struct {
 		executor  *PeriodicalExecutor
 		container *bulkContainer
@@ -18,6 +22,7 @@ type (
 	}
 )
 
+// NewBulkExecutor returns a BulkExecutor.
 func NewBulkExecutor(execute Execute, opts ...BulkOption) *BulkExecutor {
 	options := newBulkOptions()
 	for _, opt := range opts {
@@ -36,25 +41,30 @@ func NewBulkExecutor(execute Execute, opts ...BulkOption) *BulkExecutor {
 	return executor
 }
 
+// Add adds task into be.
 func (be *BulkExecutor) Add(task interface{}) error {
 	be.executor.Add(task)
 	return nil
 }
 
+// Flush forces be to flush and execute tasks.
 func (be *BulkExecutor) Flush() {
 	be.executor.Flush()
 }
 
+// Wait waits be to done with the task execution.
 func (be *BulkExecutor) Wait() {
 	be.executor.Wait()
 }
 
+// WithBulkTasks customizes a BulkExecutor with given tasks limit.
 func WithBulkTasks(tasks int) BulkOption {
 	return func(options *bulkOptions) {
 		options.cachedTasks = tasks
 	}
 }
 
+// WithBulkInterval customizes a BulkExecutor with given flush interval.
 func WithBulkInterval(duration time.Duration) BulkOption {
 	return func(options *bulkOptions) {
 		options.flushInterval = duration

core/executors/chunkexecutor.go

@@ -5,8 +5,12 @@ import "time"
 const defaultChunkSize = 1024 * 1024 // 1M
 
 type (
+	// ChunkOption defines the method to customize a ChunkExecutor.
 	ChunkOption func(options *chunkOptions)
 
+	// A ChunkExecutor is an executor to execute tasks when either requirement meets:
+	// 1. up to given chunk size
+	// 2. flush interval elapsed
 	ChunkExecutor struct {
 		executor  *PeriodicalExecutor
 		container *chunkContainer
@@ -18,6 +22,7 @@ type (
 	}
 )
 
+// NewChunkExecutor returns a ChunkExecutor.
 func NewChunkExecutor(execute Execute, opts ...ChunkOption) *ChunkExecutor {
 	options := newChunkOptions()
 	for _, opt := range opts {
@@ -36,6 +41,7 @@ func NewChunkExecutor(execute Execute, opts ...ChunkOption) *ChunkExecutor {
 	return executor
 }
 
+// Add adds task with given chunk size into ce.
 func (ce *ChunkExecutor) Add(task interface{}, size int) error {
 	ce.executor.Add(chunk{
 		val:  task,
@@ -44,20 +50,24 @@ func (ce *ChunkExecutor) Add(task interface{}, size int) error {
 	return nil
 }
 
+// Flush forces ce to flush and execute tasks.
 func (ce *ChunkExecutor) Flush() {
 	ce.executor.Flush()
 }
 
+// Wait waits the execution to be done.
 func (ce *ChunkExecutor) Wait() {
 	ce.executor.Wait()
 }
 
+// WithChunkBytes customizes a ChunkExecutor with the given chunk size.
 func WithChunkBytes(size int) ChunkOption {
 	return func(options *chunkOptions) {
 		options.chunkSize = size
 	}
 }
 
+// WithFlushInterval customizes a ChunkExecutor with the given flush interval.
 func WithFlushInterval(duration time.Duration) ChunkOption {
 	return func(options *chunkOptions) {
 		options.flushInterval = duration

core/executors/delayexecutor.go

@@ -7,6 +7,7 @@ import (
 	"github.com/tal-tech/go-zero/core/threading"
 )
 
+// A DelayExecutor delays a tasks on given delay interval.
 type DelayExecutor struct {
 	fn        func()
 	delay     time.Duration
@@ -14,6 +15,7 @@ type DelayExecutor struct {
 	lock      sync.Mutex
 }
 
+// NewDelayExecutor returns a DelayExecutor with given fn and delay.
 func NewDelayExecutor(fn func(), delay time.Duration) *DelayExecutor {
 	return &DelayExecutor{
 		fn:    fn,
@@ -21,6 +23,7 @@ func NewDelayExecutor(fn func(), delay time.Duration) *DelayExecutor {
 	}
 }
 
+// Trigger triggers the task to be executed after given delay, safe to trigger more than once.
 func (de *DelayExecutor) Trigger() {
 	de.lock.Lock()
 	defer de.lock.Unlock()

core/executors/lessexecutor.go

@@ -7,11 +7,13 @@ import (
 	"github.com/tal-tech/go-zero/core/timex"
 )
 
+// A LessExecutor is an executor to limit execution once within given time interval.
 type LessExecutor struct {
 	threshold time.Duration
 	lastTime  *syncx.AtomicDuration
 }
 
+// NewLessExecutor returns a LessExecutor with given threshold as time interval.
 func NewLessExecutor(threshold time.Duration) *LessExecutor {
 	return &LessExecutor{
 		threshold: threshold,
@@ -19,6 +21,8 @@ func NewLessExecutor(threshold time.Duration) *LessExecutor {
 	}
 }
 
+// DoOrDiscard executes or discards the task depends on if
+// another task was executed within the time interval.
 func (le *LessExecutor) DoOrDiscard(execute func()) bool {
 	now := timex.Now()
 	lastTime := le.lastTime.Load()

core/executors/periodicalexecutor.go

@@ -16,7 +16,7 @@ import (
 const idleRound = 10
 
 type (
-	// A type that satisfies executors.TaskContainer can be used as the underlying
+	// TaskContainer interface defines a type that can be used as the underlying
 	// container that used to do periodical executions.
 	TaskContainer interface {
 		// AddTask adds the task into the container.
@@ -28,6 +28,7 @@ type (
 		RemoveAll() interface{}
 	}
 
+	// A PeriodicalExecutor is an executor that periodically execute tasks.
 	PeriodicalExecutor struct {
 		commander chan interface{}
 		interval  time.Duration
@@ -43,6 +44,7 @@ type (
 	}
 )
 
+// NewPeriodicalExecutor returns a PeriodicalExecutor with given interval and container.
 func NewPeriodicalExecutor(interval time.Duration, container TaskContainer) *PeriodicalExecutor {
 	executor := &PeriodicalExecutor{
 		// buffer 1 to let the caller go quickly
@@ -61,6 +63,7 @@ func NewPeriodicalExecutor(interval time.Duration, container TaskContainer) *Per
 	return executor
 }
 
+// Add adds tasks into pe.
 func (pe *PeriodicalExecutor) Add(task interface{}) {
 	if vals, ok := pe.addAndCheck(task); ok {
 		pe.commander <- vals
@@ -68,6 +71,7 @@ func (pe *PeriodicalExecutor) Add(task interface{}) {
 	}
 }
 
+// Flush forces pe to execute tasks.
 func (pe *PeriodicalExecutor) Flush() bool {
 	pe.enterExecution()
 	return pe.executeTasks(func() interface{} {
@@ -77,12 +81,14 @@ func (pe *PeriodicalExecutor) Flush() bool {
 	}())
 }
 
+// Sync lets caller to run fn thread-safe with pe, especially for the underlying container.
 func (pe *PeriodicalExecutor) Sync(fn func()) {
 	pe.lock.Lock()
 	defer pe.lock.Unlock()
 	fn()
 }
 
+// Wait waits the execution to be done.
 func (pe *PeriodicalExecutor) Wait() {
 	pe.Flush()
 	pe.wgBarrier.Guard(func() {

core/executors/vars.go

@@ -4,4 +4,5 @@ import "time"
 
 const defaultFlushInterval = time.Second
 
+// Execute defines the method to execute tasks.
 type Execute func(tasks []interface{})

core/filex/file.go

@@ -7,6 +7,7 @@ import (
 
 const bufSize = 1024
 
+// FirstLine returns the first line of the file.
 func FirstLine(filename string) (string, error) {
 	file, err := os.Open(filename)
 	if err != nil {
@@ -17,6 +18,7 @@ func FirstLine(filename string) (string, error) {
 	return firstLine(file)
 }
 
+// LastLine returns the last line of the file.
 func LastLine(filename string) (string, error) {
 	file, err := os.Open(filename)
 	if err != nil {
@@ -69,11 +71,11 @@ func lastLine(filename string, file *os.File) (string, error) {
 
 		if buf[n-1] == '\n' {
 			buf = buf[:n-1]
-			n -= 1
+			n--
 		} else {
 			buf = buf[:n]
 		}
-		for n -= 1; n >= 0; n-- {
+		for n--; n >= 0; n-- {
 			if buf[n] == '\n' {
 				return string(append(buf[n+1:], last...)), nil
 			}

core/filex/lookup.go

@@ -5,12 +5,15 @@ import (
 	"os"
 )
 
+// OffsetRange represents a content block of a file.
 type OffsetRange struct {
 	File  string
 	Start int64
 	Stop  int64
 }
 
+// SplitLineChunks splits file into chunks.
+// The whole line are guaranteed to be split in the same chunk.
 func SplitLineChunks(filename string, chunks int) ([]OffsetRange, error) {
 	info, err := os.Stat(filename)
 	if err != nil {

core/filex/progressscanner.go

@@ -3,8 +3,11 @@ package filex
 import "gopkg.in/cheggaaa/pb.v1"
 
 type (
+	// A Scanner is used to read lines.
 	Scanner interface {
+		// Scan checks if has remaining to read.
 		Scan() bool
+		// Text returns next line.
 		Text() string
 	}
 
@@ -14,6 +17,7 @@ type (
 	}
 )
 
+// NewProgressScanner returns a Scanner with progress indicator.
 func NewProgressScanner(scanner Scanner, bar *pb.ProgressBar) Scanner {
 	return &progressScanner{
 		Scanner: scanner,

core/filex/rangereader.go

@@ -5,12 +5,14 @@ import (
 	"os"
 )
 
+// A RangeReader is used to read a range of content from a file.
 type RangeReader struct {
 	file  *os.File
 	start int64
 	stop  int64
 }
 
+// NewRangeReader returns a RangeReader, which will read the range of content from file.
 func NewRangeReader(file *os.File, start, stop int64) *RangeReader {
 	return &RangeReader{
 		file:  file,
@@ -19,6 +21,7 @@ func NewRangeReader(file *os.File, start, stop int64) *RangeReader {
 	}
 }
 
+// Read reads the range of content into p.
 func (rr *RangeReader) Read(p []byte) (n int, err error) {
 	stat, err := rr.file.Stat()
 	if err != nil {

core/fs/files.go

@@ -7,6 +7,7 @@ import (
 	"syscall"
 )
 
+// CloseOnExec makes sure closing the file on process forking.
 func CloseOnExec(file *os.File) {
 	if file != nil {
 		syscall.CloseOnExec(int(file.Fd()))

core/fx/fn.go

@@ -20,18 +20,30 @@ type (
 		workers          int
 	}
 
+	// FilterFunc defines the method to filter a Stream.
 	FilterFunc func(item interface{}) bool
+	// ForAllFunc defines the method to handle all elements in a Stream.
 	ForAllFunc func(pipe <-chan interface{})
+	// ForEachFunc defines the method to handle each element in a Stream.
 	ForEachFunc func(item interface{})
+	// GenerateFunc defines the method to send elements into a Stream.
 	GenerateFunc func(source chan<- interface{})
+	// KeyFunc defines the method to generate keys for the elements in a Stream.
 	KeyFunc func(item interface{}) interface{}
+	// LessFunc defines the method to compare the elements in a Stream.
 	LessFunc func(a, b interface{}) bool
+	// MapFunc defines the method to map each element to another object in a Stream.
 	MapFunc func(item interface{}) interface{}
+	// Option defines the method to customize a Stream.
 	Option func(opts *rxOptions)
+	// ParallelFunc defines the method to handle elements parallelly.
 	ParallelFunc func(item interface{})
+	// ReduceFunc defines the method to reduce all the elements in a Stream.
 	ReduceFunc func(pipe <-chan interface{}) (interface{}, error)
+	// WalkFunc defines the method to walk through all the elements in a Stream.
 	WalkFunc func(item interface{}, pipe chan<- interface{})
 
+	// A Stream is a stream that can be used to do stream processing.
 	Stream struct {
 		source <-chan interface{}
 	}
@@ -159,6 +171,7 @@ func (p Stream) Group(fn KeyFunc) Stream {
 	return Range(source)
 }
 
+// Head returns the first n elements in p.
 func (p Stream) Head(n int64) Stream {
 	if n < 1 {
 		panic("n must be greater than 0")
@@ -187,7 +200,7 @@ func (p Stream) Head(n int64) Stream {
 	return Range(source)
 }
 
-// Maps converts each item to another corresponding item, which means it's a 1:1 model.
+// Map converts each item to another corresponding item, which means it's a 1:1 model.
 func (p Stream) Map(fn MapFunc, opts ...Option) Stream {
 	return p.Walk(func(item interface{}, pipe chan<- interface{}) {
 		pipe <- fn(item)
@@ -274,6 +287,7 @@ func (p Stream) Split(n int) Stream {
 	return Range(source)
 }
 
+// Tail returns the last n elements in p.
 func (p Stream) Tail(n int64) Stream {
 	if n < 1 {
 		panic("n should be greater than 0")
@@ -300,9 +314,9 @@ func (p Stream) Walk(fn WalkFunc, opts ...Option) Stream {
 	option := buildOptions(opts...)
 	if option.unlimitedWorkers {
 		return p.walkUnlimited(fn, option)
-	} else {
-		return p.walkLimited(fn, option)
 	}
+
+	return p.walkLimited(fn, option)
 }
 
 func (p Stream) walkLimited(fn WalkFunc, option *rxOptions) Stream {

core/fx/parallel.go

@@ -2,6 +2,7 @@ package fx
 
 import "github.com/tal-tech/go-zero/core/threading"
 
+// Parallel runs fns parallelly and waits for done.
 func Parallel(fns ...func()) {
 	group := threading.NewRoutineGroup()
 	for _, fn := range fns {

core/fx/retry.go

@@ -5,6 +5,7 @@ import "github.com/tal-tech/go-zero/core/errorx"
 const defaultRetryTimes = 3
 
 type (
+	// RetryOption defines the method to customize DoWithRetry.
 	RetryOption func(*retryOptions)
 
 	retryOptions struct {
@@ -12,7 +13,8 @@ type (
 	}
 )
 
-func DoWithRetries(fn func() error, opts ...RetryOption) error {
+// DoWithRetry runs fn, and retries if failed. Default to retry 3 times.
+func DoWithRetry(fn func() error, opts ...RetryOption) error {
 	var options = newRetryOptions()
 	for _, opt := range opts {
 		opt(options)
@@ -30,7 +32,8 @@ func DoWithRetries(fn func() error, opts ...RetryOption) error {
 	return berr.Err()
 }
 
-func WithRetries(times int) RetryOption {
+// WithRetry customize a DoWithRetry call with given retry times.
+func WithRetry(times int) RetryOption {
 	return func(options *retryOptions) {
 		options.times = times
 	}

core/fx/retry_test.go

@@ -8,12 +8,12 @@ import (
 )
 
 func TestRetry(t *testing.T) {
-	assert.NotNil(t, DoWithRetries(func() error {
+	assert.NotNil(t, DoWithRetry(func() error {
 		return errors.New("any")
 	}))
 
 	var times int
-	assert.Nil(t, DoWithRetries(func() error {
+	assert.Nil(t, DoWithRetry(func() error {
 		times++
 		if times == defaultRetryTimes {
 			return nil
@@ -22,7 +22,7 @@ func TestRetry(t *testing.T) {
 	}))
 
 	times = 0
-	assert.NotNil(t, DoWithRetries(func() error {
+	assert.NotNil(t, DoWithRetry(func() error {
 		times++
 		if times == defaultRetryTimes+1 {
 			return nil
@@ -32,11 +32,11 @@ func TestRetry(t *testing.T) {
 
 	var total = 2 * defaultRetryTimes
 	times = 0
-	assert.Nil(t, DoWithRetries(func() error {
+	assert.Nil(t, DoWithRetry(func() error {
 		times++
 		if times == total {
 			return nil
 		}
 		return errors.New("any")
-	}, WithRetries(total)))
+	}, WithRetry(total)))
 }

core/fx/timeout.go

@@ -3,21 +3,27 @@ package fx
 import (
 	"context"
 	"time"
+
+	"github.com/tal-tech/go-zero/core/contextx"
 )
 
 var (
+	// ErrCanceled is the error returned when the context is canceled.
 	ErrCanceled = context.Canceled
+	// ErrTimeout is the error returned when the context's deadline passes.
 	ErrTimeout = context.DeadlineExceeded
 )
 
-type FxOption func() context.Context
+// DoOption defines the method to customize a DoWithTimeout call.
+type DoOption func() context.Context
 
-func DoWithTimeout(fn func() error, timeout time.Duration, opts ...FxOption) error {
+// DoWithTimeout runs fn with timeout control.
+func DoWithTimeout(fn func() error, timeout time.Duration, opts ...DoOption) error {
 	parentCtx := context.Background()
 	for _, opt := range opts {
 		parentCtx = opt()
 	}
-	ctx, cancel := context.WithTimeout(parentCtx, timeout)
+	ctx, cancel := contextx.ShrinkDeadline(parentCtx, timeout)
 	defer cancel()
 
 	done := make(chan error)
@@ -42,7 +48,8 @@ func DoWithTimeout(fn func() error, timeout time.Duration, opts ...FxOption) err
 	}
 }
 
-func WithContext(ctx context.Context) FxOption {
+// WithContext customizes a DoWithTimeout call with given ctx.
+func WithContext(ctx context.Context) DoOption {
 	return func() context.Context {
 		return ctx
 	}

core/hash/consistenthash.go

@@ -11,6 +11,7 @@ import (
 )
 
 const (
+	// TopWeight is the top weight that one entry might set.
 	TopWeight = 100
 
 	minReplicas = 100
@@ -18,10 +19,12 @@ const (
 )
 
 type (
-	HashFunc func(data []byte) uint64
+	// Func defines the hash method.
+	Func func(data []byte) uint64
 
+	// A ConsistentHash is a ring hash implementation.
 	ConsistentHash struct {
-		hashFunc HashFunc
+		hashFunc Func
 		replicas int
 		keys     []uint64
 		ring     map[uint64][]interface{}
@@ -30,11 +33,13 @@ type (
 	}
 )
 
+// NewConsistentHash returns a ConsistentHash.
 func NewConsistentHash() *ConsistentHash {
 	return NewCustomConsistentHash(minReplicas, Hash)
 }
 
-func NewCustomConsistentHash(replicas int, fn HashFunc) *ConsistentHash {
+// NewCustomConsistentHash returns a ConsistentHash with given replicas and hash func.
+func NewCustomConsistentHash(replicas int, fn Func) *ConsistentHash {
 	if replicas < minReplicas {
 		replicas = minReplicas
 	}
@@ -92,6 +97,7 @@ func (h *ConsistentHash) AddWithWeight(node interface{}, weight int) {
 	h.AddWithReplicas(node, replicas)
 }
 
+// Get returns the corresponding node from h base on the given v.
 func (h *ConsistentHash) Get(v interface{}) (interface{}, bool) {
 	h.lock.RLock()
 	defer h.lock.RUnlock()
@@ -118,6 +124,7 @@ func (h *ConsistentHash) Get(v interface{}) (interface{}, bool) {
 	}
 }
 
+// Remove removes the given node from h.
 func (h *ConsistentHash) Remove(node interface{}) {
 	nodeRepr := repr(node)
 

core/hash/consistenthash_test.go

@@ -132,8 +132,8 @@ func TestConsistentHash_RemoveInterface(t *testing.T) {
 	assert.Equal(t, 1, len(ch.nodes))
 	node, ok := ch.Get(1)
 	assert.True(t, ok)
-	assert.Equal(t, key, node.(*MockNode).Addr)
-	assert.Equal(t, 2, node.(*MockNode).Id)
+	assert.Equal(t, key, node.(*mockNode).addr)
+	assert.Equal(t, 2, node.(*mockNode).id)
 }
 
 func getKeysBeforeAndAfterFailure(t *testing.T, prefix string, index int) (map[int]string, map[int]string) {
@@ -164,18 +164,18 @@ func getKeysBeforeAndAfterFailure(t *testing.T, prefix string, index int) (map[i
 	return keys, newKeys
 }
 
-type MockNode struct {
-	Addr string
-	Id   int
+type mockNode struct {
+	addr string
+	id   int
 }
 
-func newMockNode(addr string, id int) *MockNode {
-	return &MockNode{
-		Addr: addr,
-		Id:   id,
+func newMockNode(addr string, id int) *mockNode {
+	return &mockNode{
+		addr: addr,
+		id:   id,
 	}
 }
 
-func (n *MockNode) String() string {
-	return n.Addr
+func (n *mockNode) String() string {
+	return n.addr
 }

core/hash/hash.go

@@ -7,16 +7,19 @@ import (
 	"github.com/spaolacci/murmur3"
 )
 
+// Hash returns the hash value of data.
 func Hash(data []byte) uint64 {
 	return murmur3.Sum64(data)
 }
 
+// Md5 returns the md5 bytes of data.
 func Md5(data []byte) []byte {
 	digest := md5.New()
 	digest.Write(data)
 	return digest.Sum(nil)
 }
 
+// Md5Hex returns the md5 hex string of data.
 func Md5Hex(data []byte) string {
 	return fmt.Sprintf("%x", Md5(data))
 }

core/iox/bufferpool.go

@@ -5,11 +5,13 @@ import (
 	"sync"
 )
 
+// A BufferPool is a pool to buffer bytes.Buffer objects.
 type BufferPool struct {
 	capability int
 	pool       *sync.Pool
 }
 
+// NewBufferPool returns a BufferPool.
 func NewBufferPool(capability int) *BufferPool {
 	return &BufferPool{
 		capability: capability,
@@ -21,12 +23,14 @@ func NewBufferPool(capability int) *BufferPool {
 	}
 }
 
+// Get returns a bytes.Buffer object from bp.
 func (bp *BufferPool) Get() *bytes.Buffer {
 	buf := bp.pool.Get().(*bytes.Buffer)
 	buf.Reset()
 	return buf
 }
 
+// Put returns buf into bp.
 func (bp *BufferPool) Put(buf *bytes.Buffer) {
 	if buf.Cap() < bp.capability {
 		bp.pool.Put(buf)

core/iox/nopcloser.go

@@ -10,6 +10,7 @@ func (nopCloser) Close() error {
 	return nil
 }
 
+// NopCloser returns a io.WriteCloser that does nothing on calling Close.
 func NopCloser(w io.Writer) io.WriteCloser {
 	return nopCloser{w}
 }

core/iox/read.go

@@ -16,9 +16,11 @@ type (
 		omitPrefix    string
 	}
 
+	// TextReadOption defines the method to customize the text reading functions.
 	TextReadOption func(*textReadOptions)
 )
 
+// DupReadCloser returns two io.ReadCloser that read from the first will be written to the second.
 // The first returned reader needs to be read first, because the content
 // read from it will be written to the underlying buffer of the second reader.
 func DupReadCloser(reader io.ReadCloser) (io.ReadCloser, io.ReadCloser) {
@@ -27,6 +29,7 @@ func DupReadCloser(reader io.ReadCloser) (io.ReadCloser, io.ReadCloser) {
 	return ioutil.NopCloser(tee), ioutil.NopCloser(&buf)
 }
 
+// KeepSpace customizes the reading functions to keep leading and tailing spaces.
 func KeepSpace() TextReadOption {
 	return func(o *textReadOptions) {
 		o.keepSpace = true
@@ -49,6 +52,7 @@ func ReadBytes(reader io.Reader, buf []byte) error {
 	return nil
 }
 
+// ReadText reads content from the given file with leading and tailing spaces trimmed.
 func ReadText(filename string) (string, error) {
 	content, err := ioutil.ReadFile(filename)
 	if err != nil {
@@ -58,6 +62,7 @@ func ReadText(filename string) (string, error) {
 	return strings.TrimSpace(string(content)), nil
 }
 
+// ReadTextLines reads the text lines from given file.
 func ReadTextLines(filename string, opts ...TextReadOption) ([]string, error) {
 	var readOpts textReadOptions
 	for _, opt := range opts {
@@ -90,12 +95,14 @@ func ReadTextLines(filename string, opts ...TextReadOption) ([]string, error) {
 	return lines, scanner.Err()
 }
 
+// WithoutBlank customizes the reading functions to ignore blank lines.
 func WithoutBlank() TextReadOption {
 	return func(o *textReadOptions) {
 		o.withoutBlanks = true
 	}
 }
 
+// OmitWithPrefix customizes the reading functions to ignore the lines with given leading prefix.
 func OmitWithPrefix(prefix string) TextReadOption {
 	return func(o *textReadOptions) {
 		o.omitPrefix = prefix

core/iox/textfile.go

@@ -8,6 +8,7 @@ import (
 
 const bufSize = 32 * 1024
 
+// CountLines returns the number of lines in file.
 func CountLines(file string) (int, error) {
 	f, err := os.Open(file)
 	if err != nil {

core/iox/textlinescanner.go

@@ -6,6 +6,7 @@ import (
 	"strings"
 )
 
+// A TextLineScanner is a scanner that can scan lines from given reader.
 type TextLineScanner struct {
 	reader  *bufio.Reader
 	hasNext bool
@@ -13,6 +14,7 @@ type TextLineScanner struct {
 	err     error
 }
 
+// NewTextLineScanner returns a TextLineScanner with given reader.
 func NewTextLineScanner(reader io.Reader) *TextLineScanner {
 	return &TextLineScanner{
 		reader:  bufio.NewReader(reader),
@@ -20,6 +22,7 @@ func NewTextLineScanner(reader io.Reader) *TextLineScanner {
 	}
 }
 
+// Scan checks if scanner has more lines to read.
 func (scanner *TextLineScanner) Scan() bool {
 	if !scanner.hasNext {
 		return false
@@ -37,6 +40,7 @@ func (scanner *TextLineScanner) Scan() bool {
 	return true
 }
 
+// Line returns the next available line.
 func (scanner *TextLineScanner) Line() (string, error) {
 	return scanner.line, scanner.err
 }

core/jsontype/time.go

@@ -7,32 +7,38 @@ import (
 	"github.com/globalsign/mgo/bson"
 )
 
+// MilliTime represents time.Time that works better with mongodb.
 type MilliTime struct {
 	time.Time
 }
 
+// MarshalJSON marshals mt to json bytes.
 func (mt MilliTime) MarshalJSON() ([]byte, error) {
 	return json.Marshal(mt.Milli())
 }
 
+// UnmarshalJSON unmarshals data into mt.
 func (mt *MilliTime) UnmarshalJSON(data []byte) error {
 	var milli int64
 	if err := json.Unmarshal(data, &milli); err != nil {
 		return err
-	} else {
+	}
+
 	mt.Time = time.Unix(0, milli*int64(time.Millisecond))
 	return nil
-	}
 }
 
+// GetBSON returns BSON base on mt.
 func (mt MilliTime) GetBSON() (interface{}, error) {
 	return mt.Time, nil
 }
 
+// SetBSON sets raw into mt.
 func (mt *MilliTime) SetBSON(raw bson.Raw) error {
 	return raw.Unmarshal(&mt.Time)
 }
 
+// Milli returns milliseconds for mt.
 func (mt MilliTime) Milli() int64 {
 	return mt.UnixNano() / int64(time.Millisecond)
 }

core/jsonx/json.go

@@ -8,10 +8,12 @@ import (
 	"strings"
 )
 
+// Marshal marshals v into json bytes.
 func Marshal(v interface{}) ([]byte, error) {
 	return json.Marshal(v)
 }
 
+// Unmarshal unmarshals data bytes into v.
 func Unmarshal(data []byte, v interface{}) error {
 	decoder := json.NewDecoder(bytes.NewReader(data))
 	if err := unmarshalUseNumber(decoder, v); err != nil {
@@ -21,6 +23,7 @@ func Unmarshal(data []byte, v interface{}) error {
 	return nil
 }
 
+// UnmarshalFromString unmarshals v from str.
 func UnmarshalFromString(str string, v interface{}) error {
 	decoder := json.NewDecoder(strings.NewReader(str))
 	if err := unmarshalUseNumber(decoder, v); err != nil {
@@ -30,6 +33,7 @@ func UnmarshalFromString(str string, v interface{}) error {
 	return nil
 }
 
+// UnmarshalFromReader unmarshals v from reader.
 func UnmarshalFromReader(reader io.Reader, v interface{}) error {
 	var buf strings.Builder
 	teeReader := io.TeeReader(reader, &buf)

core/lang/lang.go

@@ -1,8 +1,11 @@
 package lang
 
+// Placeholder is a placeholder object that can be used globally.
 var Placeholder PlaceholderType
 
 type (
+	// GenericType can be used to hold any type.
 	GenericType = interface{}
+	// PlaceholderType represents a placeholder type.
 	PlaceholderType = struct{}
 )

core/limit/periodlimit.go

@@ -27,9 +27,13 @@ end`
 )
 
 const (
+	// Unknown means not initialized state.
 	Unknown = iota
+	// Allowed means allowed state.
 	Allowed
+	// HitQuota means this request exactly hit the quota.
 	HitQuota
+	// OverQuota means passed the quota.
 	OverQuota
 
 	internalOverQuota = 0
@@ -37,11 +41,14 @@ const (
 	internalHitQuota  = 2
 )
 
+// ErrUnknownCode is an error that represents unknown status code.
 var ErrUnknownCode = errors.New("unknown status code")
 
 type (
-	LimitOption func(l *PeriodLimit)
+	// PeriodOption defines the method to customize a PeriodLimit.
+	PeriodOption func(l *PeriodLimit)
 
+	// A PeriodLimit is used to limit requests during a period of time.
 	PeriodLimit struct {
 		period     int
 		quota      int
@@ -51,8 +58,9 @@ type (
 	}
 )
 
+// NewPeriodLimit returns a PeriodLimit with given parameters.
 func NewPeriodLimit(period, quota int, limitStore *redis.Redis, keyPrefix string,
-	opts ...LimitOption) *PeriodLimit {
+	opts ...PeriodOption) *PeriodLimit {
 	limiter := &PeriodLimit{
 		period:     period,
 		quota:      quota,
@@ -67,6 +75,7 @@ func NewPeriodLimit(period, quota int, limitStore *redis.Redis, keyPrefix string
 	return limiter
 }
 
+// Take requests a permit, it returns the permit state.
 func (h *PeriodLimit) Take(key string) (int, error) {
 	resp, err := h.limitStore.Eval(periodScript, []string{h.keyPrefix + key}, []string{
 		strconv.Itoa(h.quota),
@@ -97,12 +106,13 @@ func (h *PeriodLimit) calcExpireSeconds() int {
 	if h.align {
 		unix := time.Now().Unix() + zoneDiff
 		return h.period - int(unix%int64(h.period))
-	} else {
-		return h.period
 	}
+
+	return h.period
 }
 
-func Align() LimitOption {
+// Align returns a func to customize a PeriodLimit with alignment.
+func Align() PeriodOption {
 	return func(l *PeriodLimit) {
 		l.align = true
 	}

core/limit/periodlimit_test.go

@@ -33,7 +33,7 @@ func TestPeriodLimit_RedisUnavailable(t *testing.T) {
 	assert.Equal(t, 0, val)
 }
 
-func testPeriodLimit(t *testing.T, opts ...LimitOption) {
+func testPeriodLimit(t *testing.T, opts ...PeriodOption) {
 	store, clean, err := redistest.CreateRedis()
 	assert.Nil(t, err)
 	defer clean()

core/load/adaptiveshedder.go

@@ -26,6 +26,7 @@ const (
 )
 
 var (
+	// ErrServiceOverloaded is returned by Shedder.Allow when the service is overloaded.
 	ErrServiceOverloaded = errors.New("service overloaded")
 
 	// default to be enabled
@@ -37,15 +38,22 @@ var (
 )
 
 type (
+	// A Promise interface is returned by Shedder.Allow to let callers tell
+	// whether the processing request is successful or not.
 	Promise interface {
+		// Pass lets the caller tell that the call is successful.
 		Pass()
+		// Fail lets the caller tell that the call is failed.
 		Fail()
 	}
 
+	// Shedder is the interface that wraps the Allow method.
 	Shedder interface {
+		// Allow returns the Promise if allowed, otherwise ErrServiceOverloaded.
 		Allow() (Promise, error)
 	}
 
+	// ShedderOption lets caller customize the Shedder.
 	ShedderOption func(opts *shedderOptions)
 
 	shedderOptions struct {
@@ -67,10 +75,13 @@ type (
 	}
 )
 
+// Disable lets callers disable load shedding.
 func Disable() {
 	enabled.Set(false)
 }
 
+// NewAdaptiveShedder returns an adaptive shedder.
+// opts can be used to customize the Shedder.
 func NewAdaptiveShedder(opts ...ShedderOption) Shedder {
 	if !enabled.True() {
 		return newNopShedder()
@@ -97,6 +108,7 @@ func NewAdaptiveShedder(opts ...ShedderOption) Shedder {
 	}
 }
 
+// Allow implements Shedder.Allow.
 func (as *adaptiveShedder) Allow() (Promise, error) {
 	if as.shouldDrop() {
 		as.dropTime.Set(timex.Now())
@@ -213,18 +225,21 @@ func (as *adaptiveShedder) systemOverloaded() bool {
 	return systemOverloadChecker(as.cpuThreshold)
 }
 
+// WithBuckets customizes the Shedder with given number of buckets.
 func WithBuckets(buckets int) ShedderOption {
 	return func(opts *shedderOptions) {
 		opts.buckets = buckets
 	}
 }
 
+// WithCpuThreshold customizes the Shedder with given cpu threshold.
 func WithCpuThreshold(threshold int64) ShedderOption {
 	return func(opts *shedderOptions) {
 		opts.cpuThreshold = threshold
 	}
 }
 
+// WithWindow customizes the Shedder with given
 func WithWindow(window time.Duration) ShedderOption {
 	return func(opts *shedderOptions) {
 		opts.window = window

core/load/sheddergroup.go

@@ -6,11 +6,13 @@ import (
 	"github.com/tal-tech/go-zero/core/syncx"
 )
 
+// A ShedderGroup is a manager to manage key based shedders.
 type ShedderGroup struct {
 	options []ShedderOption
 	manager *syncx.ResourceManager
 }
 
+// NewShedderGroup returns a ShedderGroup.
 func NewShedderGroup(opts ...ShedderOption) *ShedderGroup {
 	return &ShedderGroup{
 		options: opts,
@@ -18,6 +20,7 @@ func NewShedderGroup(opts ...ShedderOption) *ShedderGroup {
 	}
 }
 
+// GetShedder gets the Shedder for the given key.
 func (g *ShedderGroup) GetShedder(key string) Shedder {
 	shedder, _ := g.manager.GetResource(key, func() (closer io.Closer, e error) {
 		return nopCloser{

core/load/sheddingstat.go

@@ -9,6 +9,7 @@ import (
 )
 
 type (
+	// A SheddingStat is used to store the statistics for load shedding.
 	SheddingStat struct {
 		name  string
 		total int64
@@ -23,6 +24,7 @@ type (
 	}
 )
 
+// NewSheddingStat returns a SheddingStat.
 func NewSheddingStat(name string) *SheddingStat {
 	st := &SheddingStat{
 		name: name,
@@ -31,14 +33,17 @@ func NewSheddingStat(name string) *SheddingStat {
 	return st
 }
 
+// IncrementTotal increments the total requests.
 func (s *SheddingStat) IncrementTotal() {
 	atomic.AddInt64(&s.total, 1)
 }
 
+// IncrementPass increments the passed requests.
 func (s *SheddingStat) IncrementPass() {
 	atomic.AddInt64(&s.pass, 1)
 }
 
+// IncrementDrop increments the dropped requests.
 func (s *SheddingStat) IncrementDrop() {
 	atomic.AddInt64(&s.drop, 1)
 }

core/logx/config.go

@@ -1,5 +1,6 @@
 package logx
 
+// A LogConf is a logging config.
 type LogConf struct {
 	ServiceName         string `json:",optional"`
 	Mode                string `json:",default=console,options=console|file|volume"`

core/logx/durationlogger.go

@@ -12,6 +12,7 @@ const durationCallerDepth = 3
 
 type durationLogger logEntry
 
+// WithDuration returns a Logger which logs the given duration.
 func WithDuration(d time.Duration) Logger {
 	return &durationLogger{
 		Duration: timex.ReprOfDuration(d),

core/logx/lesslogger.go

@@ -1,21 +1,25 @@
 package logx
 
+// A LessLogger is a logger that control to log once during the given duration.
 type LessLogger struct {
 	*limitedExecutor
 }
 
+// NewLessLogger returns a LessLogger.
 func NewLessLogger(milliseconds int) *LessLogger {
 	return &LessLogger{
 		limitedExecutor: newLimitedExecutor(milliseconds),
 	}
 }
 
+// Error logs v into error log or discard it if more than once in the given duration.
 func (logger *LessLogger) Error(v ...interface{}) {
 	logger.logOrDiscard(func() {
 		Error(v...)
 	})
 }
 
+// Errorf logs v with format into error log or discard it if more than once in the given duration.
 func (logger *LessLogger) Errorf(format string, v ...interface{}) {
 	logger.logOrDiscard(func() {
 		Errorf(format, v...)

core/logx/lesswriter.go

@@ -7,7 +7,7 @@ type lessWriter struct {
 	writer io.Writer
 }
 
-func NewLessWriter(writer io.Writer, milliseconds int) *lessWriter {
+func newLessWriter(writer io.Writer, milliseconds int) *lessWriter {
 	return &lessWriter{
 		limitedExecutor: newLimitedExecutor(milliseconds),
 		writer:          writer,

core/logx/lesswriter_test.go

@@ -9,7 +9,7 @@ import (
 
 func TestLessWriter(t *testing.T) {
 	var builder strings.Builder
-	w := NewLessWriter(&builder, 500)
+	w := newLessWriter(&builder, 500)
 	for i := 0; i < 100; i++ {
 		_, err := w.Write([]byte("hello"))
 		assert.Nil(t, err)

core/logx/logs.go

@@ -57,8 +57,11 @@ const (
 )
 
 var (
+	// ErrLogPathNotSet is an error that indicates the log path is not set.
 	ErrLogPathNotSet = errors.New("log path must be set")
+	// ErrLogNotInitialized is an error that log is not initialized.
 	ErrLogNotInitialized = errors.New("log not initialized")
+	// ErrLogServiceNameNotSet is an error that indicates that the service name is not set.
 	ErrLogServiceNameNotSet = errors.New("log service name must be set")
 
 	writeConsole bool
@@ -89,8 +92,10 @@ type (
 		keepDays              int
 	}
 
+	// LogOption defines the method to customize the logging.
 	LogOption func(options *logOptions)
 
+	// A Logger represents a logger.
 	Logger interface {
 		Error(...interface{})
 		Errorf(string, ...interface{})
@@ -102,6 +107,7 @@ type (
 	}
 )
 
+// MustSetup sets up logging with given config c. It exits on error.
 func MustSetup(c LogConf) {
 	Must(SetUp(c))
 }
@@ -122,10 +128,12 @@ func SetUp(c LogConf) error {
 	}
 }
 
+// Alert alerts v in alert level, and the message is written to error log.
 func Alert(v string) {
 	output(errorLog, levelAlert, v)
 }
 
+// Close closes the logging.
 func Close() error {
 	if writeConsole {
 		return nil
@@ -170,6 +178,7 @@ func Close() error {
 	return nil
 }
 
+// Disable disables the logging.
 func Disable() {
 	once.Do(func() {
 		atomic.StoreUint32(&initialized, 1)
@@ -183,40 +192,49 @@ func Disable() {
 	})
 }
 
+// Error writes v into error log.
 func Error(v ...interface{}) {
 	ErrorCaller(1, v...)
 }
 
+// Errorf writes v with format into error log.
 func Errorf(format string, v ...interface{}) {
 	ErrorCallerf(1, format, v...)
 }
 
+// ErrorCaller writes v with context into error log.
 func ErrorCaller(callDepth int, v ...interface{}) {
 	errorSync(fmt.Sprint(v...), callDepth+callerInnerDepth)
 }
 
+// ErrorCallerf writes v with context in format into error log.
 func ErrorCallerf(callDepth int, format string, v ...interface{}) {
 	errorSync(fmt.Sprintf(format, v...), callDepth+callerInnerDepth)
 }
 
+// ErrorStack writes v along with call stack into error log.
 func ErrorStack(v ...interface{}) {
 	// there is newline in stack string
 	stackSync(fmt.Sprint(v...))
 }
 
+// ErrorStackf writes v along with call stack in format into error log.
 func ErrorStackf(format string, v ...interface{}) {
 	// there is newline in stack string
 	stackSync(fmt.Sprintf(format, v...))
 }
 
+// Info writes v into access log.
 func Info(v ...interface{}) {
 	infoSync(fmt.Sprint(v...))
 }
 
+// Infof writes v with format into access log.
 func Infof(format string, v ...interface{}) {
 	infoSync(fmt.Sprintf(format, v...))
 }
 
+// Must checks if err is nil, otherwise logs the err and exits.
 func Must(err error) {
 	if err != nil {
 		msg := formatWithCaller(err.Error(), 3)
@@ -226,46 +244,56 @@ func Must(err error) {
 	}
 }
 
+// SetLevel sets the logging level. It can be used to suppress some logs.
 func SetLevel(level uint32) {
 	atomic.StoreUint32(&logLevel, level)
 }
 
+// Severe writes v into severe log.
 func Severe(v ...interface{}) {
 	severeSync(fmt.Sprint(v...))
 }
 
+// Severef writes v with format into severe log.
 func Severef(format string, v ...interface{}) {
 	severeSync(fmt.Sprintf(format, v...))
 }
 
+// Slow writes v into slow log.
 func Slow(v ...interface{}) {
 	slowSync(fmt.Sprint(v...))
 }
 
+// Slowf writes v with format into slow log.
 func Slowf(format string, v ...interface{}) {
 	slowSync(fmt.Sprintf(format, v...))
 }
 
+// Stat writes v into stat log.
 func Stat(v ...interface{}) {
 	statSync(fmt.Sprint(v...))
 }
 
+// Statf writes v with format into stat log.
 func Statf(format string, v ...interface{}) {
 	statSync(fmt.Sprintf(format, v...))
 }
 
+// WithCooldownMillis customizes logging on writing call stack interval.
 func WithCooldownMillis(millis int) LogOption {
 	return func(opts *logOptions) {
 		opts.logStackCooldownMills = millis
 	}
 }
 
+// WithKeepDays customizes logging to keep logs with days.
 func WithKeepDays(days int) LogOption {
 	return func(opts *logOptions) {
 		opts.keepDays = days
 	}
 }
 
+// WithGzip customizes logging to automatically gzip the log files.
 func WithGzip() LogOption {
 	return func(opts *logOptions) {
 		opts.gzipEnabled = true
@@ -382,7 +410,7 @@ func setupWithConsole(c LogConf) {
 		errorLog = newLogWriter(log.New(os.Stderr, "", flags))
 		severeLog = newLogWriter(log.New(os.Stderr, "", flags))
 		slowLog = newLogWriter(log.New(os.Stderr, "", flags))
-		stackLog = NewLessWriter(errorLog, options.logStackCooldownMills)
+		stackLog = newLessWriter(errorLog, options.logStackCooldownMills)
 		statLog = infoLog
 	})
 }
@@ -434,7 +462,7 @@ func setupWithFiles(c LogConf) error {
 			return
 		}
 
-		stackLog = NewLessWriter(errorLog, options.logStackCooldownMills)
+		stackLog = newLessWriter(errorLog, options.logStackCooldownMills)
 	})
 
 	return err

core/logx/rotatelogger.go

@@ -26,9 +26,11 @@ const (
 	defaultFileMode = 0600
 )
 
+// ErrLogFileClosed is an error that indicates the log file is already closed.
 var ErrLogFileClosed = errors.New("error: log file closed")
 
 type (
+	// A RotateRule interface is used to define the log rotating rules.
 	RotateRule interface {
 		BackupFileName() string
 		MarkRotated()
@@ -36,6 +38,7 @@ type (
 		ShallRotate() bool
 	}
 
+	// A RotateLogger is a Logger that can rotate log files with given rules.
 	RotateLogger struct {
 		filename string
 		backup   string
@@ -50,6 +53,7 @@ type (
 		closeOnce sync.Once
 	}
 
+	// A DailyRotateRule is a rule to daily rotate the log files.
 	DailyRotateRule struct {
 		rotatedTime string
 		filename    string
@@ -59,6 +63,7 @@ type (
 	}
 )
 
+// DefaultRotateRule is a default log rotating rule, currently DailyRotateRule.
 func DefaultRotateRule(filename, delimiter string, days int, gzip bool) RotateRule {
 	return &DailyRotateRule{
 		rotatedTime: getNowDate(),
@@ -69,14 +74,17 @@ func DefaultRotateRule(filename, delimiter string, days int, gzip bool) RotateRu
 	}
 }
 
+// BackupFileName returns the backup filename on rotating.
 func (r *DailyRotateRule) BackupFileName() string {
 	return fmt.Sprintf("%s%s%s", r.filename, r.delimiter, getNowDate())
 }
 
+// MarkRotated marks the rotated time of r to be the current time.
 func (r *DailyRotateRule) MarkRotated() {
 	r.rotatedTime = getNowDate()
 }
 
+// OutdatedFiles returns the files that exceeded the keeping days.
 func (r *DailyRotateRule) OutdatedFiles() []string {
 	if r.days <= 0 {
 		return nil
@@ -113,10 +121,12 @@ func (r *DailyRotateRule) OutdatedFiles() []string {
 	return outdates
 }
 
+// ShallRotate checks if the file should be rotated.
 func (r *DailyRotateRule) ShallRotate() bool {
 	return len(r.rotatedTime) > 0 && getNowDate() != r.rotatedTime
 }
 
+// NewLogger returns a RotateLogger with given filename and rule, etc.
 func NewLogger(filename string, rule RotateRule, compress bool) (*RotateLogger, error) {
 	l := &RotateLogger{
 		filename: filename,
@@ -133,6 +143,7 @@ func NewLogger(filename string, rule RotateRule, compress bool) (*RotateLogger,
 	return l, nil
 }
 
+// Close closes l.
 func (l *RotateLogger) Close() error {
 	var err error
 
@@ -163,9 +174,9 @@ func (l *RotateLogger) Write(data []byte) (int, error) {
 func (l *RotateLogger) getBackupFilename() string {
 	if len(l.backup) == 0 {
 		return l.rule.BackupFileName()
-	} else {
-		return l.backup
 	}
+
+	return l.backup
 }
 
 func (l *RotateLogger) init() error {

core/logx/tracelogger.go

@@ -67,6 +67,7 @@ func (l *traceLogger) write(writer io.Writer, level, content string) {
 	outputJson(writer, l)
 }
 
+// WithContext sets ctx to log, for keeping tracing information.
 func WithContext(ctx context.Context) Logger {
 	return &traceLogger{
 		ctx: ctx,

core/logx/tracelogger_test.go

@@ -13,8 +13,8 @@ import (
 )
 
 const (
-	mockTraceId = "mock-trace-id"
-	mockSpanId  = "mock-span-id"
+	mockTraceID = "mock-trace-id"
+	mockSpanID  = "mock-span-id"
 )
 
 var mock tracespec.Trace = new(mockTrace)
@@ -24,8 +24,8 @@ func TestTraceLog(t *testing.T) {
 	atomic.StoreUint32(&initialized, 1)
 	ctx := context.WithValue(context.Background(), tracespec.TracingKey, mock)
 	WithContext(ctx).(*traceLogger).write(&buf, levelInfo, testlog)
-	assert.True(t, strings.Contains(buf.String(), mockTraceId))
-	assert.True(t, strings.Contains(buf.String(), mockSpanId))
+	assert.True(t, strings.Contains(buf.String(), mockTraceID))
+	assert.True(t, strings.Contains(buf.String(), mockSpanID))
 }
 
 func TestTraceError(t *testing.T) {
@@ -36,12 +36,12 @@ func TestTraceError(t *testing.T) {
 	l := WithContext(ctx).(*traceLogger)
 	SetLevel(InfoLevel)
 	l.WithDuration(time.Second).Error(testlog)
-	assert.True(t, strings.Contains(buf.String(), mockTraceId))
-	assert.True(t, strings.Contains(buf.String(), mockSpanId))
+	assert.True(t, strings.Contains(buf.String(), mockTraceID))
+	assert.True(t, strings.Contains(buf.String(), mockSpanID))
 	buf.Reset()
 	l.WithDuration(time.Second).Errorf(testlog)
-	assert.True(t, strings.Contains(buf.String(), mockTraceId))
-	assert.True(t, strings.Contains(buf.String(), mockSpanId))
+	assert.True(t, strings.Contains(buf.String(), mockTraceID))
+	assert.True(t, strings.Contains(buf.String(), mockSpanID))
 }
 
 func TestTraceInfo(t *testing.T) {
@@ -52,12 +52,12 @@ func TestTraceInfo(t *testing.T) {
 	l := WithContext(ctx).(*traceLogger)
 	SetLevel(InfoLevel)
 	l.WithDuration(time.Second).Info(testlog)
-	assert.True(t, strings.Contains(buf.String(), mockTraceId))
-	assert.True(t, strings.Contains(buf.String(), mockSpanId))
+	assert.True(t, strings.Contains(buf.String(), mockTraceID))
+	assert.True(t, strings.Contains(buf.String(), mockSpanID))
 	buf.Reset()
 	l.WithDuration(time.Second).Infof(testlog)
-	assert.True(t, strings.Contains(buf.String(), mockTraceId))
-	assert.True(t, strings.Contains(buf.String(), mockSpanId))
+	assert.True(t, strings.Contains(buf.String(), mockTraceID))
+	assert.True(t, strings.Contains(buf.String(), mockSpanID))
 }
 
 func TestTraceSlow(t *testing.T) {
@@ -68,12 +68,12 @@ func TestTraceSlow(t *testing.T) {
 	l := WithContext(ctx).(*traceLogger)
 	SetLevel(InfoLevel)
 	l.WithDuration(time.Second).Slow(testlog)
-	assert.True(t, strings.Contains(buf.String(), mockTraceId))
-	assert.True(t, strings.Contains(buf.String(), mockSpanId))
+	assert.True(t, strings.Contains(buf.String(), mockTraceID))
+	assert.True(t, strings.Contains(buf.String(), mockSpanID))
 	buf.Reset()
 	l.WithDuration(time.Second).Slowf(testlog)
-	assert.True(t, strings.Contains(buf.String(), mockTraceId))
-	assert.True(t, strings.Contains(buf.String(), mockSpanId))
+	assert.True(t, strings.Contains(buf.String(), mockTraceID))
+	assert.True(t, strings.Contains(buf.String(), mockSpanID))
 }
 
 func TestTraceWithoutContext(t *testing.T) {
@@ -83,22 +83,22 @@ func TestTraceWithoutContext(t *testing.T) {
 	l := WithContext(context.Background()).(*traceLogger)
 	SetLevel(InfoLevel)
 	l.WithDuration(time.Second).Info(testlog)
-	assert.False(t, strings.Contains(buf.String(), mockTraceId))
-	assert.False(t, strings.Contains(buf.String(), mockSpanId))
+	assert.False(t, strings.Contains(buf.String(), mockTraceID))
+	assert.False(t, strings.Contains(buf.String(), mockSpanID))
 	buf.Reset()
 	l.WithDuration(time.Second).Infof(testlog)
-	assert.False(t, strings.Contains(buf.String(), mockTraceId))
-	assert.False(t, strings.Contains(buf.String(), mockSpanId))
+	assert.False(t, strings.Contains(buf.String(), mockTraceID))
+	assert.False(t, strings.Contains(buf.String(), mockSpanID))
 }
 
 type mockTrace struct{}
 
 func (t mockTrace) TraceId() string {
-	return mockTraceId
+	return mockTraceID
 }
 
 func (t mockTrace) SpanId() string {
-	return mockSpanId
+	return mockSpanID
 }
 
 func (t mockTrace) Finish() {

core/mapping/fieldoptions.go

@@ -35,9 +35,9 @@ func (o *fieldOptionsWithContext) fromString() bool {
 func (o *fieldOptionsWithContext) getDefault() (string, bool) {
 	if o == nil {
 		return "", false
-	} else {
-		return o.Default, len(o.Default) > 0
 	}
+
+	return o.Default, len(o.Default) > 0
 }
 
 func (o *fieldOptionsWithContext) optional() bool {
@@ -55,9 +55,9 @@ func (o *fieldOptionsWithContext) options() []string {
 func (o *fieldOptions) optionalDep() string {
 	if o == nil {
 		return ""
-	} else {
-		return o.OptionalDep
 	}
+
+	return o.OptionalDep
 }
 
 func (o *fieldOptions) toOptionsWithContext(key string, m Valuer, fullName string) (
@@ -77,29 +77,29 @@ func (o *fieldOptions) toOptionsWithContext(key string, m Valuer, fullName strin
 			_, selfOn := m.Value(key)
 			if baseOn == selfOn {
 				return nil, fmt.Errorf("set value for either %q or %q in %q", dep, key, fullName)
-			} else {
-				optional = baseOn
 			}
+
+			optional = baseOn
 		} else {
 			_, baseOn := m.Value(dep)
 			_, selfOn := m.Value(key)
 			if baseOn != selfOn {
 				return nil, fmt.Errorf("values for %q and %q should be both provided or both not in %q",
 					dep, key, fullName)
-			} else {
-				optional = !baseOn
 			}
+
+			optional = !baseOn
 		}
 	}
 
 	if o.fieldOptionsWithContext.Optional == optional {
 		return &o.fieldOptionsWithContext, nil
-	} else {
+	}
+
 	return &fieldOptionsWithContext{
 		FromString: o.FromString,
 		Optional:   optional,
 		Options:    o.Options,
 		Default:    o.Default,
 	}, nil
-	}
 }

core/mapping/jsonunmarshaler.go

@@ -10,10 +10,12 @@ const jsonTagKey = "json"
 
 var jsonUnmarshaler = NewUnmarshaler(jsonTagKey)
 
+// UnmarshalJsonBytes unmarshals content into v.
 func UnmarshalJsonBytes(content []byte, v interface{}) error {
 	return unmarshalJsonBytes(content, v, jsonUnmarshaler)
 }
 
+// UnmarshalJsonReader unmarshals content from reader into v.
 func UnmarshalJsonReader(reader io.Reader, v interface{}) error {
 	return unmarshalJsonReader(reader, v, jsonUnmarshaler)
 }

core/mapping/jsonunmarshaler_test.go

@@ -485,41 +485,41 @@ func TestUnmarshalBytesMap(t *testing.T) {
 func TestUnmarshalBytesMapStruct(t *testing.T) {
 	var c struct {
 		Persons map[string]struct {
-			Id   int
+			ID   int
 			Name string `json:"name,optional"`
 		}
 	}
-	content := []byte(`{"Persons": {"first": {"Id": 1, "name": "kevin"}}}`)
+	content := []byte(`{"Persons": {"first": {"ID": 1, "name": "kevin"}}}`)
 
 	assert.Nil(t, UnmarshalJsonBytes(content, &c))
 	assert.Equal(t, 1, len(c.Persons))
-	assert.Equal(t, 1, c.Persons["first"].Id)
+	assert.Equal(t, 1, c.Persons["first"].ID)
 	assert.Equal(t, "kevin", c.Persons["first"].Name)
 }
 
 func TestUnmarshalBytesMapStructPtr(t *testing.T) {
 	var c struct {
 		Persons map[string]*struct {
-			Id   int
+			ID   int
 			Name string `json:"name,optional"`
 		}
 	}
-	content := []byte(`{"Persons": {"first": {"Id": 1, "name": "kevin"}}}`)
+	content := []byte(`{"Persons": {"first": {"ID": 1, "name": "kevin"}}}`)
 
 	assert.Nil(t, UnmarshalJsonBytes(content, &c))
 	assert.Equal(t, 1, len(c.Persons))
-	assert.Equal(t, 1, c.Persons["first"].Id)
+	assert.Equal(t, 1, c.Persons["first"].ID)
 	assert.Equal(t, "kevin", c.Persons["first"].Name)
 }
 
 func TestUnmarshalBytesMapStructMissingPartial(t *testing.T) {
 	var c struct {
 		Persons map[string]*struct {
-			Id   int
+			ID   int
 			Name string
 		}
 	}
-	content := []byte(`{"Persons": {"first": {"Id": 1}}}`)
+	content := []byte(`{"Persons": {"first": {"ID": 1}}}`)
 
 	assert.NotNil(t, UnmarshalJsonBytes(content, &c))
 }
@@ -527,21 +527,21 @@ func TestUnmarshalBytesMapStructMissingPartial(t *testing.T) {
 func TestUnmarshalBytesMapStructOptional(t *testing.T) {
 	var c struct {
 		Persons map[string]*struct {
-			Id   int
+			ID   int
 			Name string `json:"name,optional"`
 		}
 	}
-	content := []byte(`{"Persons": {"first": {"Id": 1}}}`)
+	content := []byte(`{"Persons": {"first": {"ID": 1}}}`)
 
 	assert.Nil(t, UnmarshalJsonBytes(content, &c))
 	assert.Equal(t, 1, len(c.Persons))
-	assert.Equal(t, 1, c.Persons["first"].Id)
+	assert.Equal(t, 1, c.Persons["first"].ID)
 }
 
 func TestUnmarshalBytesMapEmptyStructSlice(t *testing.T) {
 	var c struct {
 		Persons map[string][]struct {
-			Id   int
+			ID   int
 			Name string `json:"name,optional"`
 		}
 	}
@@ -555,22 +555,22 @@ func TestUnmarshalBytesMapEmptyStructSlice(t *testing.T) {
 func TestUnmarshalBytesMapStructSlice(t *testing.T) {
 	var c struct {
 		Persons map[string][]struct {
-			Id   int
+			ID   int
 			Name string `json:"name,optional"`
 		}
 	}
-	content := []byte(`{"Persons": {"first": [{"Id": 1, "name": "kevin"}]}}`)
+	content := []byte(`{"Persons": {"first": [{"ID": 1, "name": "kevin"}]}}`)
 
 	assert.Nil(t, UnmarshalJsonBytes(content, &c))
 	assert.Equal(t, 1, len(c.Persons))
-	assert.Equal(t, 1, c.Persons["first"][0].Id)
+	assert.Equal(t, 1, c.Persons["first"][0].ID)
 	assert.Equal(t, "kevin", c.Persons["first"][0].Name)
 }
 
 func TestUnmarshalBytesMapEmptyStructPtrSlice(t *testing.T) {
 	var c struct {
 		Persons map[string][]*struct {
-			Id   int
+			ID   int
 			Name string `json:"name,optional"`
 		}
 	}
@@ -584,26 +584,26 @@ func TestUnmarshalBytesMapEmptyStructPtrSlice(t *testing.T) {
 func TestUnmarshalBytesMapStructPtrSlice(t *testing.T) {
 	var c struct {
 		Persons map[string][]*struct {
-			Id   int
+			ID   int
 			Name string `json:"name,optional"`
 		}
 	}
-	content := []byte(`{"Persons": {"first": [{"Id": 1, "name": "kevin"}]}}`)
+	content := []byte(`{"Persons": {"first": [{"ID": 1, "name": "kevin"}]}}`)
 
 	assert.Nil(t, UnmarshalJsonBytes(content, &c))
 	assert.Equal(t, 1, len(c.Persons))
-	assert.Equal(t, 1, c.Persons["first"][0].Id)
+	assert.Equal(t, 1, c.Persons["first"][0].ID)
 	assert.Equal(t, "kevin", c.Persons["first"][0].Name)
 }
 
 func TestUnmarshalBytesMapStructPtrSliceMissingPartial(t *testing.T) {
 	var c struct {
 		Persons map[string][]*struct {
-			Id   int
+			ID   int
 			Name string
 		}
 	}
-	content := []byte(`{"Persons": {"first": [{"Id": 1}]}}`)
+	content := []byte(`{"Persons": {"first": [{"ID": 1}]}}`)
 
 	assert.NotNil(t, UnmarshalJsonBytes(content, &c))
 }
@@ -611,15 +611,15 @@ func TestUnmarshalBytesMapStructPtrSliceMissingPartial(t *testing.T) {
 func TestUnmarshalBytesMapStructPtrSliceOptional(t *testing.T) {
 	var c struct {
 		Persons map[string][]*struct {
-			Id   int
+			ID   int
 			Name string `json:"name,optional"`
 		}
 	}
-	content := []byte(`{"Persons": {"first": [{"Id": 1}]}}`)
+	content := []byte(`{"Persons": {"first": [{"ID": 1}]}}`)
 
 	assert.Nil(t, UnmarshalJsonBytes(content, &c))
 	assert.Equal(t, 1, len(c.Persons))
-	assert.Equal(t, 1, c.Persons["first"][0].Id)
+	assert.Equal(t, 1, c.Persons["first"][0].ID)
 }
 
 func TestUnmarshalStructOptional(t *testing.T) {

core/mapping/unmarshaler.go

@@ -33,23 +33,27 @@ var (
 )
 
 type (
+	// A Unmarshaler is used to unmarshal with given tag key.
 	Unmarshaler struct {
 		key  string
 		opts unmarshalOptions
 	}
 
+	// UnmarshalOption defines the method to customize a Unmarshaler.
+	UnmarshalOption func(*unmarshalOptions)
+
 	unmarshalOptions struct {
 		fromString bool
 	}
 
 	keyCache map[string][]string
-	UnmarshalOption func(*unmarshalOptions)
 )
 
 func init() {
 	cacheKeys.Store(make(keyCache))
 }
 
+// NewUnmarshaler returns a Unmarshaler.
 func NewUnmarshaler(key string, opts ...UnmarshalOption) *Unmarshaler {
 	unmarshaler := Unmarshaler{
 		key: key,
@@ -62,14 +66,17 @@ func NewUnmarshaler(key string, opts ...UnmarshalOption) *Unmarshaler {
 	return &unmarshaler
 }
 
+// UnmarshalKey unmarshals m into v with tag key.
 func UnmarshalKey(m map[string]interface{}, v interface{}) error {
 	return keyUnmarshaler.Unmarshal(m, v)
 }
 
+// Unmarshal unmarshals m into v.
 func (u *Unmarshaler) Unmarshal(m map[string]interface{}, v interface{}) error {
 	return u.UnmarshalValuer(MapValuer(m), v)
 }
 
+// UnmarshalValuer unmarshals m into v.
 func (u *Unmarshaler) UnmarshalValuer(m Valuer, v interface{}) error {
 	return u.unmarshalWithFullName(m, v, "")
 }
@@ -114,9 +121,9 @@ func (u *Unmarshaler) processAnonymousField(field reflect.StructField, value ref
 
 	if options.optional() {
 		return u.processAnonymousFieldOptional(field, value, key, m, fullName)
-	} else {
-		return u.processAnonymousFieldRequired(field, value, m, fullName)
 	}
+
+	return u.processAnonymousFieldRequired(field, value, m, fullName)
 }
 
 func (u *Unmarshaler) processAnonymousFieldOptional(field reflect.StructField, value reflect.Value,
@@ -184,9 +191,9 @@ func (u *Unmarshaler) processField(field reflect.StructField, value reflect.Valu
 
 	if field.Anonymous {
 		return u.processAnonymousField(field, value, m, fullName)
-	} else {
-		return u.processNamedField(field, value, m, fullName)
 	}
+
+	return u.processNamedField(field, value, m, fullName)
 }
 
 func (u *Unmarshaler) processFieldNotFromString(field reflect.StructField, value reflect.Value,
@@ -200,7 +207,7 @@ func (u *Unmarshaler) processFieldNotFromString(field reflect.StructField, value
 	case valueKind == reflect.Map && typeKind == reflect.Struct:
 		return u.processFieldStruct(field, value, mapValue, fullName)
 	case valueKind == reflect.String && typeKind == reflect.Slice:
-		return u.fillSliceFromString(fieldType, value, mapValue, fullName)
+		return u.fillSliceFromString(fieldType, value, mapValue)
 	case valueKind == reflect.String && derefedFieldType == durationType:
 		return fillDurationValue(fieldType.Kind(), value, mapValue.(string))
 	default:
@@ -319,9 +326,9 @@ func (u *Unmarshaler) processNamedField(field reflect.StructField, value reflect
 	mapValue, hasValue := getValue(m, key)
 	if hasValue {
 		return u.processNamedFieldWithValue(field, value, mapValue, key, opts, fullName)
-	} else {
-		return u.processNamedFieldWithoutValue(field, value, opts, fullName)
 	}
+
+	return u.processNamedFieldWithoutValue(field, value, opts, fullName)
 }
 
 func (u *Unmarshaler) processNamedFieldWithValue(field reflect.StructField, value reflect.Value,
@@ -329,9 +336,9 @@ func (u *Unmarshaler) processNamedFieldWithValue(field reflect.StructField, valu
 	if mapValue == nil {
 		if opts.optional() {
 			return nil
-		} else {
-			return fmt.Errorf("field %s mustn't be nil", key)
 		}
+
+		return fmt.Errorf("field %s mustn't be nil", key)
 	}
 
 	maybeNewValue(field, value)
@@ -464,8 +471,7 @@ func (u *Unmarshaler) fillSlice(fieldType reflect.Type, value reflect.Value, map
 	return nil
 }
 
-func (u *Unmarshaler) fillSliceFromString(fieldType reflect.Type, value reflect.Value,
-	mapValue interface{}, fullName string) error {
+func (u *Unmarshaler) fillSliceFromString(fieldType reflect.Type, value reflect.Value, mapValue interface{}) error {
 	var slice []interface{}
 	if err := jsonx.UnmarshalFromString(mapValue.(string), &slice); err != nil {
 		return err
@@ -591,6 +597,7 @@ func (u *Unmarshaler) parseOptionsWithContext(field reflect.StructField, m Value
 	return key, optsWithContext, nil
 }
 
+// WithStringValues customizes a Unmarshaler with number values from strings.
 func WithStringValues() UnmarshalOption {
 	return func(opt *unmarshalOptions) {
 		opt.fromString = true

core/mapping/unmarshaler_test.go

@@ -754,13 +754,13 @@ func TestUnmarshalJsonNumberInt64(t *testing.T) {
 		strValue := strconv.FormatInt(intValue, 10)
 		var number = json.Number(strValue)
 		m := map[string]interface{}{
-			"Id": number,
+			"ID": number,
 		}
 		var v struct {
-			Id int64
+			ID int64
 		}
 		assert.Nil(t, UnmarshalKey(m, &v))
-		assert.Equal(t, intValue, v.Id)
+		assert.Equal(t, intValue, v.ID)
 	}
 }
 
@@ -770,13 +770,13 @@ func TestUnmarshalJsonNumberUint64(t *testing.T) {
 		strValue := strconv.FormatUint(intValue, 10)
 		var number = json.Number(strValue)
 		m := map[string]interface{}{
-			"Id": number,
+			"ID": number,
 		}
 		var v struct {
-			Id uint64
+			ID uint64
 		}
 		assert.Nil(t, UnmarshalKey(m, &v))
-		assert.Equal(t, intValue, v.Id)
+		assert.Equal(t, intValue, v.ID)
 	}
 }
 
@@ -786,15 +786,15 @@ func TestUnmarshalJsonNumberUint64Ptr(t *testing.T) {
 		strValue := strconv.FormatUint(intValue, 10)
 		var number = json.Number(strValue)
 		m := map[string]interface{}{
-			"Id": number,
+			"ID": number,
 		}
 		var v struct {
-			Id *uint64
+			ID *uint64
 		}
 		ast := assert.New(t)
 		ast.Nil(UnmarshalKey(m, &v))
-		ast.NotNil(v.Id)
-		ast.Equal(intValue, *v.Id)
+		ast.NotNil(v.ID)
+		ast.Equal(intValue, *v.ID)
 	}
 }
 
@@ -1061,38 +1061,38 @@ func TestUnmarshalWithOptionsAndSet(t *testing.T) {
 
 func TestUnmarshalNestedKey(t *testing.T) {
 	var c struct {
-		Id int `json:"Persons.first.Id"`
+		ID int `json:"Persons.first.ID"`
 	}
 	m := map[string]interface{}{
 		"Persons": map[string]interface{}{
 			"first": map[string]interface{}{
-				"Id": 1,
+				"ID": 1,
 			},
 		},
 	}
 
 	assert.Nil(t, NewUnmarshaler("json").Unmarshal(m, &c))
-	assert.Equal(t, 1, c.Id)
+	assert.Equal(t, 1, c.ID)
 }
 
 func TestUnmarhsalNestedKeyArray(t *testing.T) {
 	var c struct {
 		First []struct {
-			Id int
+			ID int
 		} `json:"Persons.first"`
 	}
 	m := map[string]interface{}{
 		"Persons": map[string]interface{}{
 			"first": []map[string]interface{}{
-				{"Id": 1},
-				{"Id": 2},
+				{"ID": 1},
+				{"ID": 2},
 			},
 		},
 	}
 
 	assert.Nil(t, NewUnmarshaler("json").Unmarshal(m, &c))
 	assert.Equal(t, 2, len(c.First))
-	assert.Equal(t, 1, c.First[0].Id)
+	assert.Equal(t, 1, c.First[0].ID)
 }
 
 func TestUnmarshalAnonymousOptionalRequiredProvided(t *testing.T) {

core/mapping/utils.go

@@ -45,6 +45,7 @@ type (
 	}
 )
 
+// Deref dereferences a type, if pointer type, returns its element type.
 func Deref(t reflect.Type) reflect.Type {
 	if t.Kind() == reflect.Ptr {
 		t = t.Elem()
@@ -53,6 +54,7 @@ func Deref(t reflect.Type) reflect.Type {
 	return t
 }
 
+// Repr returns the string representation of v.
 func Repr(v interface{}) string {
 	if v == nil {
 		return ""
@@ -69,46 +71,10 @@ func Repr(v interface{}) string {
 		val = val.Elem()
 	}
 
-	switch vt := val.Interface().(type) {
-	case bool:
-		return strconv.FormatBool(vt)
-	case error:
-		return vt.Error()
-	case float32:
-		return strconv.FormatFloat(float64(vt), 'f', -1, 32)
-	case float64:
-		return strconv.FormatFloat(vt, 'f', -1, 64)
-	case fmt.Stringer:
-		return vt.String()
-	case int:
-		return strconv.Itoa(vt)
-	case int8:
-		return strconv.Itoa(int(vt))
-	case int16:
-		return strconv.Itoa(int(vt))
-	case int32:
-		return strconv.Itoa(int(vt))
-	case int64:
-		return strconv.FormatInt(vt, 10)
-	case string:
-		return vt
-	case uint:
-		return strconv.FormatUint(uint64(vt), 10)
-	case uint8:
-		return strconv.FormatUint(uint64(vt), 10)
-	case uint16:
-		return strconv.FormatUint(uint64(vt), 10)
-	case uint32:
-		return strconv.FormatUint(uint64(vt), 10)
-	case uint64:
-		return strconv.FormatUint(vt, 10)
-	case []byte:
-		return string(vt)
-	default:
-		return fmt.Sprint(val.Interface())
-	}
+	return reprOfValue(val)
 }
 
+// ValidatePtr validates v if it's a valid pointer.
 func ValidatePtr(v *reflect.Value) error {
 	// sequence is very important, IsNil must be called after checking Kind() with reflect.Ptr,
 	// panic otherwise
@@ -124,23 +90,26 @@ func convertType(kind reflect.Kind, str string) (interface{}, error) {
 	case reflect.Bool:
 		return str == "1" || strings.ToLower(str) == "true", nil
 	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
-		if intValue, err := strconv.ParseInt(str, 10, 64); err != nil {
+		intValue, err := strconv.ParseInt(str, 10, 64)
+		if err != nil {
 			return 0, fmt.Errorf("the value %q cannot parsed as int", str)
-		} else {
+		}
+
 		return intValue, nil
-		}
 	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
-		if uintValue, err := strconv.ParseUint(str, 10, 64); err != nil {
+		uintValue, err := strconv.ParseUint(str, 10, 64)
+		if err != nil {
 			return 0, fmt.Errorf("the value %q cannot parsed as uint", str)
-		} else {
+		}
+
 		return uintValue, nil
-		}
 	case reflect.Float32, reflect.Float64:
-		if floatValue, err := strconv.ParseFloat(str, 64); err != nil {
+		floatValue, err := strconv.ParseFloat(str, 64)
+		if err != nil {
 			return 0, fmt.Errorf("the value %q cannot parsed as float", str)
-		} else {
-			return floatValue, nil
 		}
+
+		return floatValue, nil
 	case reflect.String:
 		return str, nil
 	default:
@@ -160,46 +129,8 @@ func doParseKeyAndOptions(field reflect.StructField, value string) (string, *fie
 	var fieldOpts fieldOptions
 	for _, segment := range options {
 		option := strings.TrimSpace(segment)
-		switch {
-		case option == stringOption:
-			fieldOpts.FromString = true
-		case strings.HasPrefix(option, optionalOption):
-			segs := strings.Split(option, equalToken)
-			switch len(segs) {
-			case 1:
-				fieldOpts.Optional = true
-			case 2:
-				fieldOpts.Optional = true
-				fieldOpts.OptionalDep = segs[1]
-			default:
-				return "", nil, fmt.Errorf("field %s has wrong optional", field.Name)
-			}
-		case option == optionalOption:
-			fieldOpts.Optional = true
-		case strings.HasPrefix(option, optionsOption):
-			segs := strings.Split(option, equalToken)
-			if len(segs) != 2 {
-				return "", nil, fmt.Errorf("field %s has wrong options", field.Name)
-			} else {
-				fieldOpts.Options = strings.Split(segs[1], optionSeparator)
-			}
-		case strings.HasPrefix(option, defaultOption):
-			segs := strings.Split(option, equalToken)
-			if len(segs) != 2 {
-				return "", nil, fmt.Errorf("field %s has wrong default option", field.Name)
-			} else {
-				fieldOpts.Default = strings.TrimSpace(segs[1])
-			}
-		case strings.HasPrefix(option, rangeOption):
-			segs := strings.Split(option, equalToken)
-			if len(segs) != 2 {
-				return "", nil, fmt.Errorf("field %s has wrong range", field.Name)
-			}
-			if nr, err := parseNumberRange(segs[1]); err != nil {
+		if err := parseOption(&fieldOpts, field.Name, option); err != nil {
 			return "", nil, err
-			} else {
-				fieldOpts.Range = nr
-			}
 		}
 	}
 
@@ -343,6 +274,95 @@ func parseNumberRange(str string) (*numberRange, error) {
 	}, nil
 }
 
+func parseOption(fieldOpts *fieldOptions, fieldName string, option string) error {
+	switch {
+	case option == stringOption:
+		fieldOpts.FromString = true
+	case strings.HasPrefix(option, optionalOption):
+		segs := strings.Split(option, equalToken)
+		switch len(segs) {
+		case 1:
+			fieldOpts.Optional = true
+		case 2:
+			fieldOpts.Optional = true
+			fieldOpts.OptionalDep = segs[1]
+		default:
+			return fmt.Errorf("field %s has wrong optional", fieldName)
+		}
+	case option == optionalOption:
+		fieldOpts.Optional = true
+	case strings.HasPrefix(option, optionsOption):
+		segs := strings.Split(option, equalToken)
+		if len(segs) != 2 {
+			return fmt.Errorf("field %s has wrong options", fieldName)
+		}
+
+		fieldOpts.Options = strings.Split(segs[1], optionSeparator)
+	case strings.HasPrefix(option, defaultOption):
+		segs := strings.Split(option, equalToken)
+		if len(segs) != 2 {
+			return fmt.Errorf("field %s has wrong default option", fieldName)
+		}
+
+		fieldOpts.Default = strings.TrimSpace(segs[1])
+	case strings.HasPrefix(option, rangeOption):
+		segs := strings.Split(option, equalToken)
+		if len(segs) != 2 {
+			return fmt.Errorf("field %s has wrong range", fieldName)
+		}
+
+		nr, err := parseNumberRange(segs[1])
+		if err != nil {
+			return err
+		}
+
+		fieldOpts.Range = nr
+	}
+
+	return nil
+}
+
+func reprOfValue(val reflect.Value) string {
+	switch vt := val.Interface().(type) {
+	case bool:
+		return strconv.FormatBool(vt)
+	case error:
+		return vt.Error()
+	case float32:
+		return strconv.FormatFloat(float64(vt), 'f', -1, 32)
+	case float64:
+		return strconv.FormatFloat(vt, 'f', -1, 64)
+	case fmt.Stringer:
+		return vt.String()
+	case int:
+		return strconv.Itoa(vt)
+	case int8:
+		return strconv.Itoa(int(vt))
+	case int16:
+		return strconv.Itoa(int(vt))
+	case int32:
+		return strconv.Itoa(int(vt))
+	case int64:
+		return strconv.FormatInt(vt, 10)
+	case string:
+		return vt
+	case uint:
+		return strconv.FormatUint(uint64(vt), 10)
+	case uint8:
+		return strconv.FormatUint(uint64(vt), 10)
+	case uint16:
+		return strconv.FormatUint(uint64(vt), 10)
+	case uint32:
+		return strconv.FormatUint(uint64(vt), 10)
+	case uint64:
+		return strconv.FormatUint(vt, 10)
+	case []byte:
+		return string(vt)
+	default:
+		return fmt.Sprint(val.Interface())
+	}
+}
+
 func setMatchedPrimitiveValue(kind reflect.Kind, value reflect.Value, v interface{}) error {
 	switch kind {
 	case reflect.Bool:

core/mapping/valuer.go

@@ -1,13 +1,17 @@
 package mapping
 
 type (
+	// A Valuer interface defines the way to get values from the underlying object with keys.
 	Valuer interface {
+		// Value gets the value associated with the given key.
 		Value(key string) (interface{}, bool)
 	}
 
+	// A MapValuer is a map that can use Value method to get values with given keys.
 	MapValuer map[string]interface{}
 )
 
+// Value gets the value associated with the given key from mv.
 func (mv MapValuer) Value(key string) (interface{}, bool) {
 	v, ok := mv[key]
 	return v, ok

core/mapping/yamlunmarshaler.go

@@ -13,15 +13,18 @@ import (
 const yamlTagKey = "json"
 
 var (
+	// ErrUnsupportedType is an error that indicates the config format is not supported.
 	ErrUnsupportedType = errors.New("only map-like configs are suported")
 
 	yamlUnmarshaler = NewUnmarshaler(yamlTagKey)
 )
 
+// UnmarshalYamlBytes unmarshals content into v.
 func UnmarshalYamlBytes(content []byte, v interface{}) error {
 	return unmarshalYamlBytes(content, v, yamlUnmarshaler)
 }
 
+// UnmarshalYamlReader unmarshals content from reader into v.
 func UnmarshalYamlReader(reader io.Reader, v interface{}) error {
 	return unmarshalYamlReader(reader, v, yamlUnmarshaler)
 }
@@ -34,9 +37,9 @@ func unmarshalYamlBytes(content []byte, v interface{}, unmarshaler *Unmarshaler)
 
 	if m, ok := o.(map[string]interface{}); ok {
 		return unmarshaler.Unmarshal(m, v)
-	} else {
-		return ErrUnsupportedType
 	}
+
+	return ErrUnsupportedType
 }
 
 func unmarshalYamlReader(reader io.Reader, v interface{}, unmarshaler *Unmarshaler) error {

core/mapping/yamlunmarshaler_test.go

@@ -502,49 +502,49 @@ func TestUnmarshalYamlBytesMap(t *testing.T) {
 func TestUnmarshalYamlBytesMapStruct(t *testing.T) {
 	var c struct {
 		Persons map[string]struct {
-			Id   int
+			ID   int
 			Name string `json:"name,optional"`
 		}
 	}
 	content := []byte(`Persons:
   first:
-    Id: 1
+    ID: 1
     name: kevin`)
 
 	assert.Nil(t, UnmarshalYamlBytes(content, &c))
 	assert.Equal(t, 1, len(c.Persons))
-	assert.Equal(t, 1, c.Persons["first"].Id)
+	assert.Equal(t, 1, c.Persons["first"].ID)
 	assert.Equal(t, "kevin", c.Persons["first"].Name)
 }
 
 func TestUnmarshalYamlBytesMapStructPtr(t *testing.T) {
 	var c struct {
 		Persons map[string]*struct {
-			Id   int
+			ID   int
 			Name string `json:"name,optional"`
 		}
 	}
 	content := []byte(`Persons:
   first:
-    Id: 1
+    ID: 1
     name: kevin`)
 
 	assert.Nil(t, UnmarshalYamlBytes(content, &c))
 	assert.Equal(t, 1, len(c.Persons))
-	assert.Equal(t, 1, c.Persons["first"].Id)
+	assert.Equal(t, 1, c.Persons["first"].ID)
 	assert.Equal(t, "kevin", c.Persons["first"].Name)
 }
 
 func TestUnmarshalYamlBytesMapStructMissingPartial(t *testing.T) {
 	var c struct {
 		Persons map[string]*struct {
-			Id   int
+			ID   int
 			Name string
 		}
 	}
 	content := []byte(`Persons:
   first:
-    Id: 1`)
+    ID: 1`)
 
 	assert.NotNil(t, UnmarshalYamlBytes(content, &c))
 }
@@ -552,41 +552,41 @@ func TestUnmarshalYamlBytesMapStructMissingPartial(t *testing.T) {
 func TestUnmarshalYamlBytesMapStructOptional(t *testing.T) {
 	var c struct {
 		Persons map[string]*struct {
-			Id   int
+			ID   int
 			Name string `json:"name,optional"`
 		}
 	}
 	content := []byte(`Persons:
   first:
-    Id: 1`)
+    ID: 1`)
 
 	assert.Nil(t, UnmarshalYamlBytes(content, &c))
 	assert.Equal(t, 1, len(c.Persons))
-	assert.Equal(t, 1, c.Persons["first"].Id)
+	assert.Equal(t, 1, c.Persons["first"].ID)
 }
 
 func TestUnmarshalYamlBytesMapStructSlice(t *testing.T) {
 	var c struct {
 		Persons map[string][]struct {
-			Id   int
+			ID   int
 			Name string `json:"name,optional"`
 		}
 	}
 	content := []byte(`Persons:
   first:
-  - Id: 1
+  - ID: 1
     name: kevin`)
 
 	assert.Nil(t, UnmarshalYamlBytes(content, &c))
 	assert.Equal(t, 1, len(c.Persons))
-	assert.Equal(t, 1, c.Persons["first"][0].Id)
+	assert.Equal(t, 1, c.Persons["first"][0].ID)
 	assert.Equal(t, "kevin", c.Persons["first"][0].Name)
 }
 
 func TestUnmarshalYamlBytesMapEmptyStructSlice(t *testing.T) {
 	var c struct {
 		Persons map[string][]struct {
-			Id   int
+			ID   int
 			Name string `json:"name,optional"`
 		}
 	}
@@ -601,25 +601,25 @@ func TestUnmarshalYamlBytesMapEmptyStructSlice(t *testing.T) {
 func TestUnmarshalYamlBytesMapStructPtrSlice(t *testing.T) {
 	var c struct {
 		Persons map[string][]*struct {
-			Id   int
+			ID   int
 			Name string `json:"name,optional"`
 		}
 	}
 	content := []byte(`Persons:
   first:
-  - Id: 1
+  - ID: 1
     name: kevin`)
 
 	assert.Nil(t, UnmarshalYamlBytes(content, &c))
 	assert.Equal(t, 1, len(c.Persons))
-	assert.Equal(t, 1, c.Persons["first"][0].Id)
+	assert.Equal(t, 1, c.Persons["first"][0].ID)
 	assert.Equal(t, "kevin", c.Persons["first"][0].Name)
 }
 
 func TestUnmarshalYamlBytesMapEmptyStructPtrSlice(t *testing.T) {
 	var c struct {
 		Persons map[string][]*struct {
-			Id   int
+			ID   int
 			Name string `json:"name,optional"`
 		}
 	}
@@ -634,13 +634,13 @@ func TestUnmarshalYamlBytesMapEmptyStructPtrSlice(t *testing.T) {
 func TestUnmarshalYamlBytesMapStructPtrSliceMissingPartial(t *testing.T) {
 	var c struct {
 		Persons map[string][]*struct {
-			Id   int
+			ID   int
 			Name string
 		}
 	}
 	content := []byte(`Persons:
   first:
-  - Id: 1`)
+  - ID: 1`)
 
 	assert.NotNil(t, UnmarshalYamlBytes(content, &c))
 }
@@ -648,17 +648,17 @@ func TestUnmarshalYamlBytesMapStructPtrSliceMissingPartial(t *testing.T) {
 func TestUnmarshalYamlBytesMapStructPtrSliceOptional(t *testing.T) {
 	var c struct {
 		Persons map[string][]*struct {
-			Id   int
+			ID   int
 			Name string `json:"name,optional"`
 		}
 	}
 	content := []byte(`Persons:
   first:
-  - Id: 1`)
+  - ID: 1`)
 
 	assert.Nil(t, UnmarshalYamlBytes(content, &c))
 	assert.Equal(t, 1, len(c.Persons))
-	assert.Equal(t, 1, c.Persons["first"][0].Id)
+	assert.Equal(t, 1, c.Persons["first"][0].ID)
 }
 
 func TestUnmarshalYamlStructOptional(t *testing.T) {

core/mathx/entropy.go

@@ -4,6 +4,7 @@ import "math"
 
 const epsilon = 1e-6
 
+// CalcEntropy calculates the entropy of m.
 func CalcEntropy(m map[interface{}]int) float64 {
 	if len(m) == 0 || len(m) == 1 {
 		return 1

core/mathx/int.go

@@ -1,17 +1,19 @@
 package mathx
 
+// MaxInt returns the larger one of a and b.
 func MaxInt(a, b int) int {
 	if a > b {
 		return a
-	} else {
-		return b
 	}
+
+	return b
 }
 
+// MinInt returns the smaller one of a and b.
 func MinInt(a, b int) int {
 	if a < b {
 		return a
-	} else {
-		return b
 	}
+
+	return b
 }

core/mathx/proba.go

@@ -6,18 +6,21 @@ import (
 	"time"
 )
 
+// A Proba is used to test if true on given probability.
 type Proba struct {
 	// rand.New(...) returns a non thread safe object
 	r    *rand.Rand
 	lock sync.Mutex
 }
 
+// NewProba returns a Proba.
 func NewProba() *Proba {
 	return &Proba{
 		r: rand.New(rand.NewSource(time.Now().UnixNano())),
 	}
 }
 
+// TrueOnProba checks if true on given probability.
 func (p *Proba) TrueOnProba(proba float64) (truth bool) {
 	p.lock.Lock()
 	truth = p.r.Float64() < proba

core/mathx/unstable.go

@@ -6,12 +6,14 @@ import (
 	"time"
 )
 
+// A Unstable is used to generate random value around the mean value base on given deviation.
 type Unstable struct {
 	deviation float64
 	r         *rand.Rand
 	lock      *sync.Mutex
 }
 
+// NewUnstable returns a Unstable.
 func NewUnstable(deviation float64) Unstable {
 	if deviation < 0 {
 		deviation = 0
@@ -26,6 +28,7 @@ func NewUnstable(deviation float64) Unstable {
 	}
 }
 
+// AroundDuration returns a random duration with given base and deviation.
 func (u Unstable) AroundDuration(base time.Duration) time.Duration {
 	u.lock.Lock()
 	val := time.Duration((1 + u.deviation - 2*u.deviation*u.r.Float64()) * float64(base))
@@ -33,6 +36,7 @@ func (u Unstable) AroundDuration(base time.Duration) time.Duration {
 	return val
 }
 
+// AroundInt returns a randome int64 with given base and deviation.
 func (u Unstable) AroundInt(base int64) int64 {
 	u.lock.Lock()
 	val := int64((1 + u.deviation - 2*u.deviation*u.r.Float64()) * float64(base))