feat: add logc package, support AddGlobalFields for both logc and logx. (#2463)

* feat: add logc package

* feat: add logc, add AddGlobalFields for both logc and logx

* chore: add benchmarks

* chore: add more tests

* chore: simplify globalFields in logx

* chore: remove outdated comments

core/logx/fields_test.go

@@ -1,12 +1,36 @@
 package logx
 
 import (
+	"bytes"
 	"context"
+	"encoding/json"
+	"sync"
+	"sync/atomic"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
 )
 
+func TestAddGlobalFields(t *testing.T) {
+	var buf bytes.Buffer
+	writer := NewWriter(&buf)
+	old := Reset()
+	SetWriter(writer)
+	defer SetWriter(old)
+
+	Info("hello")
+	buf.Reset()
+
+	AddGlobalFields(Field("a", "1"), Field("b", "2"))
+	AddGlobalFields(Field("c", "3"))
+	Info("world")
+	var m map[string]interface{}
+	assert.NoError(t, json.Unmarshal(buf.Bytes(), &m))
+	assert.Equal(t, "1", m["a"])
+	assert.Equal(t, "2", m["b"])
+	assert.Equal(t, "3", m["c"])
+}
+
 func TestContextWithFields(t *testing.T) {
 	ctx := ContextWithFields(context.Background(), Field("a", 1), Field("b", 2))
 	vals := ctx.Value(fieldsContextKey)
@@ -16,6 +40,15 @@ func TestContextWithFields(t *testing.T) {
 	assert.EqualValues(t, []LogField{Field("a", 1), Field("b", 2)}, fields)
 }
 
+func TestWithFields(t *testing.T) {
+	ctx := WithFields(context.Background(), Field("a", 1), Field("b", 2))
+	vals := ctx.Value(fieldsContextKey)
+	assert.NotNil(t, vals)
+	fields, ok := vals.([]LogField)
+	assert.True(t, ok)
+	assert.EqualValues(t, []LogField{Field("a", 1), Field("b", 2)}, fields)
+}
+
 func TestWithFieldsAppend(t *testing.T) {
 	var dummyKey struct{}
 	ctx := context.WithValue(context.Background(), dummyKey, "dummy")
@@ -33,3 +66,39 @@ func TestWithFieldsAppend(t *testing.T) {
 		Field("d", 4),
 	}, fields)
 }
+
+func BenchmarkAtomicValue(b *testing.B) {
+	b.ReportAllocs()
+
+	var container atomic.Value
+	vals := []LogField{
+		Field("a", "b"),
+		Field("c", "d"),
+		Field("e", "f"),
+	}
+	container.Store(&vals)
+
+	for i := 0; i < b.N; i++ {
+		val := container.Load()
+		if val != nil {
+			_ = *val.(*[]LogField)
+		}
+	}
+}
+
+func BenchmarkRWMutex(b *testing.B) {
+	b.ReportAllocs()
+
+	var lock sync.RWMutex
+	vals := []LogField{
+		Field("a", "b"),
+		Field("c", "d"),
+		Field("e", "f"),
+	}
+
+	for i := 0; i < b.N; i++ {
+		lock.RLock()
+		_ = vals
+		lock.RUnlock()
+	}
+}