accesslog: improvements and new features

relative to: #1601 and #1624

middleware/accesslog/json.go

@@ -1,54 +1,50 @@
 package accesslog
 
 import (
-	"encoding/json"
 	"io"
-	"sync"
+	"strings"
+
+	jsoniter "github.com/json-iterator/go"
 )
 
 // JSON is a Formatter type for JSON logs.
 type JSON struct {
-	Prefix, Indent string
-	EscapeHTML     bool
+	// Indent in spaces.
+	// Note that, if set to > 0 then jsoniter is used instead of easyjson.
+	Indent     string
+	EscapeHTML bool
 
-	enc         *json.Encoder
-	mu          sync.Mutex
-	lockEncoder bool
+	jsoniter jsoniter.API
+	ac       *AccessLog
 }
 
 // SetOutput creates the json encoder writes to the "dest".
 // It's called automatically by the middleware when this Formatter is used.
 func (f *JSON) SetOutput(dest io.Writer) {
-	if dest == nil {
-		return
+	f.ac, _ = dest.(*AccessLog)
+	if indentStep := strings.Count(f.Indent, " "); indentStep > 0 {
+		f.jsoniter = jsoniter.Config{
+			TagKey:        "json",
+			IndentionStep: indentStep,
+			EscapeHTML:    f.EscapeHTML,
+			SortMapKeys:   true,
+		}.Froze()
 	}
-
-	// All logs share the same accesslog's writer and it cannot change during serve-time.
-	enc := json.NewEncoder(dest)
-	enc.SetEscapeHTML(f.EscapeHTML)
-	enc.SetIndent(f.Prefix, f.Indent)
-	f.lockEncoder = f.Prefix != "" || f.Indent != ""
-	f.enc = enc
 }
 
 // Format prints the logs in JSON format.
 // Writes to the destination directly,
 // locks on each Format call.
 func (f *JSON) Format(log *Log) (bool, error) {
-	// f.mu.Lock()
-	// ^ This lock is not required as the writer is
-	// protected with mutex if necessary or configurated to do so.
-	// However, if we navigate through the
-	// internal encoding's source code we'll see that it
-	// uses a field for its indent buffer,
-	// therefore it's only useful when Prefix or Indent was not empty.
-	if f.lockEncoder {
-		f.mu.Lock()
-	}
-	err := f.enc.Encode(log)
-	if f.lockEncoder {
-		f.mu.Unlock()
+	if f.jsoniter != nil {
+		b, err := f.jsoniter.Marshal(log)
+		if err != nil {
+			return true, err
+		}
+		f.ac.Write(append(b, newLine))
+		return true, nil
 	}
 
+	err := f.writeEasyJSON(log)
 	return true, err
 }