fix golint issues in zrpc (#531)

zrpc/internal/clientinterceptors/breakerinterceptor.go

@@ -9,6 +9,7 @@ import (
 	"google.golang.org/grpc"
 )
 
+// BreakerInterceptor is an interceptor that acts as a circuit breaker.
 func BreakerInterceptor(ctx context.Context, method string, req, reply interface{},
 	cc *grpc.ClientConn, invoker grpc.UnaryInvoker, opts ...grpc.CallOption) error {
 	breakerName := path.Join(cc.Target(), method)

zrpc/internal/clientinterceptors/durationinterceptor.go

@@ -12,6 +12,7 @@ import (
 
 const slowThreshold = time.Millisecond * 500
 
+// DurationInterceptor is an interceptor that logs the processing time.
 func DurationInterceptor(ctx context.Context, method string, req, reply interface{},
 	cc *grpc.ClientConn, invoker grpc.UnaryInvoker, opts ...grpc.CallOption) error {
 	serverName := path.Join(cc.Target(), method)

zrpc/internal/clientinterceptors/prometheusinterceptor.go

@@ -32,6 +32,7 @@ var (
 	})
 )
 
+// PrometheusInterceptor is an interceptor that reports to prometheus server.
 func PrometheusInterceptor(ctx context.Context, method string, req, reply interface{},
 	cc *grpc.ClientConn, invoker grpc.UnaryInvoker, opts ...grpc.CallOption) error {
 	startTime := timex.Now()

zrpc/internal/clientinterceptors/timeoutinterceptor.go

@@ -8,6 +8,7 @@ import (
 	"google.golang.org/grpc"
 )
 
+// TimeoutInterceptor is an interceptor that controls timeout.
 func TimeoutInterceptor(timeout time.Duration) grpc.UnaryClientInterceptor {
 	return func(ctx context.Context, method string, req, reply interface{}, cc *grpc.ClientConn,
 		invoker grpc.UnaryInvoker, opts ...grpc.CallOption) error {

zrpc/internal/clientinterceptors/tracinginterceptor.go

@@ -8,6 +8,7 @@ import (
 	"google.golang.org/grpc/metadata"
 )
 
+// TracingInterceptor is an interceptor that handles tracing.
 func TracingInterceptor(ctx context.Context, method string, req, reply interface{},
 	cc *grpc.ClientConn, invoker grpc.UnaryInvoker, opts ...grpc.CallOption) error {
 	ctx, span := trace.StartClientSpan(ctx, cc.Target(), method)