bump fluent/fluent-logger-golang v1.4.0

- Add RequestAck to enable at-least-once message transferring
- Add Async option to update sending message in asynchronous way
- Deprecate AsyncConnect (Use Async instead)

full diff: https://github.com/fluent/fluent-logger-golang/compare/v1.3.0...v1.4.0

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

daemon/logger/fluentd/fluentd.go

@@ -133,7 +133,7 @@ func New(info logger.Info) (logger.Logger, error) {
 		BufferLimit:        bufferLimit,
 		RetryWait:          retryWait,
 		MaxRetry:           maxRetries,
-		AsyncConnect:       asyncConnect,
+		Async:              asyncConnect,
 		SubSecondPrecision: subSecondPrecision,
 	}
 

vendor.conf

@@ -95,7 +95,7 @@ github.com/golang/protobuf                          aa810b61a9c79d51363740d207bb
 github.com/Graylog2/go-gelf                         4143646226541087117ff2f83334ea48b3201841
 
 # fluent-logger-golang deps
-github.com/fluent/fluent-logger-golang              8bbc2356beaf021b04c9bd5cdc76ea5a7ccb40ec # v1.3.0
+github.com/fluent/fluent-logger-golang              7a6c9dcd7f14c2ed5d8c55c11b894e5455ee311b # v1.4.0
 github.com/philhofer/fwd                            bb6d471dc95d4fe11e432687f8b70ff496cf3136 # v1.0.0
 github.com/tinylib/msgp                             3b556c64540842d4f82967be066a7f7fffc3adad
 

vendor/github.com/fluent/fluent-logger-golang/README.md

@@ -64,6 +64,16 @@ f := fluent.New(fluent.Config{FluentPort: 80, FluentHost: "example.com"})
 Sets the timeout for Write call of logger.Post.
 Since the default is zero value, Write will not time out.
 
+### Async
+
+Enable asynchronous I/O (connect and write) for sending events to Fluentd.
+The default is false.
+
+### RequestAck
+
+Sets whether to request acknowledgment from Fluentd to increase the reliability
+of the connection. The default is false.
+
 ## Tests
 ```
 go test

vendor/github.com/fluent/fluent-logger-golang/fluent/fluent.go

@@ -6,12 +6,17 @@ import (
 	"fmt"
 	"math"
 	"net"
+	"os"
 	"reflect"
 	"strconv"
 	"sync"
 	"time"
 
+	"bytes"
+	"encoding/base64"
+	"encoding/binary"
 	"github.com/tinylib/msgp/msgp"
+	"math/rand"
 )
 
 const (
@@ -21,8 +26,9 @@ const (
 	defaultPort                   = 24224
 	defaultTimeout                = 3 * time.Second
 	defaultWriteTimeout           = time.Duration(0) // Write() will not time out
-	defaultBufferLimit            = 8 * 1024 * 1024
+	defaultBufferLimit            = 8 * 1024
 	defaultRetryWait              = 500
+	defaultMaxRetryWait           = 60000
 	defaultMaxRetry               = 13
 	defaultReconnectWaitIncreRate = 1.5
 	// Default sub-second precision value to false since it is only compatible
@@ -40,24 +46,36 @@ type Config struct {
 	BufferLimit      int           `json:"buffer_limit"`
 	RetryWait        int           `json:"retry_wait"`
 	MaxRetry         int           `json:"max_retry"`
+	MaxRetryWait     int           `json:"max_retry_wait"`
 	TagPrefix        string        `json:"tag_prefix"`
+	Async            bool          `json:"async"`
+	// Deprecated: Use Async instead
 	AsyncConnect  bool `json:"async_connect"`
 	MarshalAsJSON bool `json:"marshal_as_json"`
 
 	// Sub-second precision timestamps are only possible for those using fluentd
 	// v0.14+ and serializing their messages with msgpack.
 	SubSecondPrecision bool `json:"sub_second_precision"`
+
+	// RequestAck sends the chunk option with a unique ID. The server will
+	// respond with an acknowledgement. This option improves the reliability
+	// of the message transmission.
+	RequestAck bool `json:"request_ack"`
+}
+
+type msgToSend struct {
+	data []byte
+	ack  string
 }
 
 type Fluent struct {
 	Config
 
-	mubuff  sync.Mutex
-	pending []byte
+	pending chan *msgToSend
+	wg      sync.WaitGroup
 
 	muconn sync.Mutex
 	conn   net.Conn
-	reconnecting bool
 }
 
 // New creates a new Logger.
@@ -89,11 +107,22 @@ func New(config Config) (f *Fluent, err error) {
 	if config.MaxRetry == 0 {
 		config.MaxRetry = defaultMaxRetry
 	}
+	if config.MaxRetryWait == 0 {
+		config.MaxRetryWait = defaultMaxRetryWait
+	}
 	if config.AsyncConnect {
-		f = &Fluent{Config: config, reconnecting: true}
-		go f.reconnect()
+		fmt.Fprintf(os.Stderr, "fluent#New: AsyncConnect is now deprecated, please use Async instead")
+		config.Async = config.Async || config.AsyncConnect
+	}
+	if config.Async {
+		f = &Fluent{
+			Config:  config,
+			pending: make(chan *msgToSend, config.BufferLimit),
+		}
+		f.wg.Add(1)
+		go f.run()
 	} else {
-		f = &Fluent{Config: config, reconnecting: false}
+		f = &Fluent{Config: config}
 		err = f.connect()
 	}
 	return
@@ -173,28 +202,25 @@ func (f *Fluent) PostWithTime(tag string, tm time.Time, message interface{}) err
 }
 
 func (f *Fluent) EncodeAndPostData(tag string, tm time.Time, message interface{}) error {
-	var data []byte
+	var msg *msgToSend
 	var err error
-	if data, err = f.EncodeData(tag, tm, message); err != nil {
+	if msg, err = f.EncodeData(tag, tm, message); err != nil {
 		return fmt.Errorf("fluent#EncodeAndPostData: can't convert '%#v' to msgpack:%v", message, err)
 	}
-	return f.postRawData(data)
+	return f.postRawData(msg)
 }
 
 // Deprecated: Use EncodeAndPostData instead
-func (f *Fluent) PostRawData(data []byte) {
-	f.postRawData(data)
+func (f *Fluent) PostRawData(msg *msgToSend) {
+	f.postRawData(msg)
 }
 
-func (f *Fluent) postRawData(data []byte) error {
-	if err := f.appendBuffer(data); err != nil {
-		return err
+func (f *Fluent) postRawData(msg *msgToSend) error {
+	if f.Config.Async {
+		return f.appendBuffer(msg)
 	}
-	if err := f.send(); err != nil {
-		f.close()
-		return err
-	}
-	return nil
+	// Synchronous write
+	return f.write(msg)
 }
 
 // For sending forward protocol adopted JSON
@@ -207,43 +233,80 @@ type MessageChunk struct {
 // So, it should write JSON marshaler by hand.
 func (chunk *MessageChunk) MarshalJSON() ([]byte, error) {
 	data, err := json.Marshal(chunk.message.Record)
-	return []byte(fmt.Sprintf("[\"%s\",%d,%s,null]", chunk.message.Tag,
-		chunk.message.Time, data)), err
+	if err != nil {
+		return nil, err
+	}
+	option, err := json.Marshal(chunk.message.Option)
+	if err != nil {
+		return nil, err
+	}
+	return []byte(fmt.Sprintf("[\"%s\",%d,%s,%s]", chunk.message.Tag,
+		chunk.message.Time, data, option)), err
 }
 
-func (f *Fluent) EncodeData(tag string, tm time.Time, message interface{}) (data []byte, err error) {
+// getUniqueID returns a base64 encoded unique ID that can be used for chunk/ack
+// mechanism, see
+// https://github.com/fluent/fluentd/wiki/Forward-Protocol-Specification-v1#option
+func getUniqueID(timeUnix int64) (string, error) {
+	buf := bytes.NewBuffer(nil)
+	enc := base64.NewEncoder(base64.StdEncoding, buf)
+	if err := binary.Write(enc, binary.LittleEndian, timeUnix); err != nil {
+		enc.Close()
+		return "", err
+	}
+	if err := binary.Write(enc, binary.LittleEndian, rand.Uint64()); err != nil {
+		enc.Close()
+		return "", err
+	}
+	// encoder needs to be closed before buf.String(), defer does not work
+	// here
+	enc.Close()
+	return buf.String(), nil
+}
+
+func (f *Fluent) EncodeData(tag string, tm time.Time, message interface{}) (msg *msgToSend, err error) {
+	option := make(map[string]string)
+	msg = &msgToSend{}
 	timeUnix := tm.Unix()
+	if f.Config.RequestAck {
+		var err error
+		msg.ack, err = getUniqueID(timeUnix)
+		if err != nil {
+			return nil, err
+		}
+		option["chunk"] = msg.ack
+	}
 	if f.Config.MarshalAsJSON {
-		msg := Message{Tag: tag, Time: timeUnix, Record: message}
-		chunk := &MessageChunk{message: msg}
-		data, err = json.Marshal(chunk)
+		m := Message{Tag: tag, Time: timeUnix, Record: message, Option: option}
+		chunk := &MessageChunk{message: m}
+		msg.data, err = json.Marshal(chunk)
 	} else if f.Config.SubSecondPrecision {
-		msg := &MessageExt{Tag: tag, Time: EventTime(tm), Record: message}
-		data, err = msg.MarshalMsg(nil)
+		m := &MessageExt{Tag: tag, Time: EventTime(tm), Record: message, Option: option}
+		msg.data, err = m.MarshalMsg(nil)
 	} else {
-		msg := &Message{Tag: tag, Time: timeUnix, Record: message}
-		data, err = msg.MarshalMsg(nil)
+		m := &Message{Tag: tag, Time: timeUnix, Record: message, Option: option}
+		msg.data, err = m.MarshalMsg(nil)
 	}
 	return
 }
 
-// Close closes the connection.
+// Close closes the connection, waiting for pending logs to be sent
 func (f *Fluent) Close() (err error) {
-	if len(f.pending) > 0 {
-		err = f.send()
+	if f.Config.Async {
+		close(f.pending)
+		f.wg.Wait()
 	}
 	f.close()
 	return
 }
 
 // appendBuffer appends data to buffer with lock.
-func (f *Fluent) appendBuffer(data []byte) error {
-	f.mubuff.Lock()
-	defer f.mubuff.Unlock()
-	if len(f.pending)+len(data) > f.Config.BufferLimit {
-		return errors.New(fmt.Sprintf("fluent#appendBuffer: Buffer full, limit %v", f.Config.BufferLimit))
+func (f *Fluent) appendBuffer(msg *msgToSend) error {
+	select {
+	case f.pending <- msg:
+	default:
+		return fmt.Errorf("fluent#appendBuffer: Buffer full, limit %v", f.Config.BufferLimit)
 	}
-	f.pending = append(f.pending, data...)
 	return nil
 }
 
@@ -259,8 +322,6 @@ func (f *Fluent) close() {
 
 // connect establishes a new connection using the specified transport.
 func (f *Fluent) connect() (err error) {
-	f.muconn.Lock()
-	defer f.muconn.Unlock()
 
 	switch f.Config.FluentNetwork {
 	case "tcp":
@@ -270,63 +331,78 @@ func (f *Fluent) connect() (err error) {
 	default:
 		err = net.UnknownNetworkError(f.Config.FluentNetwork)
 	}
-
-	if err == nil {
-		f.reconnecting = false
+	return err
 }
+
+func (f *Fluent) run() {
+	for {
+		select {
+		case entry, ok := <-f.pending:
+			if !ok {
+				f.wg.Done()
 				return
 			}
+			err := f.write(entry)
+			if err != nil {
+				fmt.Fprintf(os.Stderr, "[%s] Unable to send logs to fluentd, reconnecting...\n", time.Now().Format(time.RFC3339))
+			}
+		}
+	}
+}
 
 func e(x, y float64) int {
 	return int(math.Pow(x, y))
 }
 
-func (f *Fluent) reconnect() {
-	for i := 0; ; i++ {
-		err := f.connect()
-		if err == nil {
-			f.send()
-			return
-		}
-		if i == f.Config.MaxRetry {
-			// TODO: What we can do when connection failed MaxRetry times?
-			panic("fluent#reconnect: failed to reconnect!")
-		}
-		waitTime := f.Config.RetryWait * e(defaultReconnectWaitIncreRate, float64(i-1))
-		time.Sleep(time.Duration(waitTime) * time.Millisecond)
-	}
-}
+func (f *Fluent) write(msg *msgToSend) error {
 
-func (f *Fluent) send() error {
+	for i := 0; i < f.Config.MaxRetry; i++ {
+
+		// Connect if needed
 		f.muconn.Lock()
-	defer f.muconn.Unlock()
-
 		if f.conn == nil {
-		if f.reconnecting == false {
-			f.reconnecting = true
-			go f.reconnect()
+			err := f.connect()
+			if err != nil {
+				f.muconn.Unlock()
+				waitTime := f.Config.RetryWait * e(defaultReconnectWaitIncreRate, float64(i-1))
+				if waitTime > f.Config.MaxRetryWait {
+					waitTime = f.Config.MaxRetryWait
 				}
-		return errors.New("fluent#send: can't send logs, client is reconnecting")
+				time.Sleep(time.Duration(waitTime) * time.Millisecond)
+				continue
 			}
+		}
+		f.muconn.Unlock()
 
-	f.mubuff.Lock()
-	defer f.mubuff.Unlock()
-
-	var err error
-	if len(f.pending) > 0 {
+		// We're connected, write msg
 		t := f.Config.WriteTimeout
 		if time.Duration(0) < t {
 			f.conn.SetWriteDeadline(time.Now().Add(t))
 		} else {
 			f.conn.SetWriteDeadline(time.Time{})
 		}
-		_, err = f.conn.Write(f.pending)
+		_, err := f.conn.Write(msg.data)
 		if err != nil {
-			f.conn.Close()
-			f.conn = nil
+			f.close()
 		} else {
-			f.pending = f.pending[:0]
+			// Acknowledgment check
+			if msg.ack != "" {
+				resp := &AckResp{}
+				if f.Config.MarshalAsJSON {
+					dec := json.NewDecoder(f.conn)
+					err = dec.Decode(resp)
+				} else {
+					r := msgp.NewReader(f.conn)
+					err = resp.DecodeMsg(r)
+				}
+				if err != nil || resp.Ack != msg.ack {
+					f.close()
+					continue
 				}
 			}
 			return err
 		}
+	}
+
+	return fmt.Errorf("fluent#write: failed to reconnect, max retry: %v", f.Config.MaxRetry)
+}

vendor/github.com/fluent/fluent-logger-golang/fluent/proto.go

@@ -18,7 +18,7 @@ type Entry struct {
 type Forward struct {
 	Tag     string  `msg:"tag"`
 	Entries []Entry `msg:"entries"`
-	Option  interface{} `msg:"option"`
+	Option  map[string]string
 }
 
 //msgp:tuple Message
@@ -26,7 +26,7 @@ type Message struct {
 	Tag    string      `msg:"tag"`
 	Time   int64       `msg:"time"`
 	Record interface{} `msg:"record"`
-	Option interface{} `msg:"option"`
+	Option map[string]string
 }
 
 //msgp:tuple MessageExt
@@ -34,7 +34,11 @@ type MessageExt struct {
 	Tag    string      `msg:"tag"`
 	Time   EventTime   `msg:"time,extension"`
 	Record interface{} `msg:"record"`
-	Option interface{} `msg:"option"`
+	Option map[string]string
+}
+
+type AckResp struct {
+	Ack string `json:"ack" msg:"ack"`
 }
 
 // EventTime is an extension to the serialized time value. It builds in support

vendor/github.com/fluent/fluent-logger-golang/fluent/proto_gen.go

@@ -1,30 +1,134 @@
 package fluent
 
-// NOTE: THIS FILE WAS PRODUCED BY THE
-// MSGP CODE GENERATION TOOL (github.com/tinylib/msgp)
-// DO NOT EDIT
+// Code generated by github.com/tinylib/msgp DO NOT EDIT.
 
 import (
 	"github.com/tinylib/msgp/msgp"
 )
 
 // DecodeMsg implements msgp.Decodable
-func (z *Entry) DecodeMsg(dc *msgp.Reader) (err error) {
-	var zxvk uint32
-	zxvk, err = dc.ReadArrayHeader()
+func (z *AckResp) DecodeMsg(dc *msgp.Reader) (err error) {
+	var field []byte
+	_ = field
+	var zb0001 uint32
+	zb0001, err = dc.ReadMapHeader()
+	if err != nil {
+		err = msgp.WrapError(err)
+		return
+	}
+	for zb0001 > 0 {
+		zb0001--
+		field, err = dc.ReadMapKeyPtr()
+		if err != nil {
+			err = msgp.WrapError(err)
+			return
+		}
+		switch msgp.UnsafeString(field) {
+		case "ack":
+			z.Ack, err = dc.ReadString()
+			if err != nil {
+				err = msgp.WrapError(err, "Ack")
+				return
+			}
+		default:
+			err = dc.Skip()
+			if err != nil {
+				err = msgp.WrapError(err)
+				return
+			}
+		}
+	}
+	return
+}
+
+// EncodeMsg implements msgp.Encodable
+func (z AckResp) EncodeMsg(en *msgp.Writer) (err error) {
+	// map header, size 1
+	// write "ack"
+	err = en.Append(0x81, 0xa3, 0x61, 0x63, 0x6b)
 	if err != nil {
 		return
 	}
-	if zxvk != 2 {
-		err = msgp.ArrayError{Wanted: 2, Got: zxvk}
+	err = en.WriteString(z.Ack)
+	if err != nil {
+		err = msgp.WrapError(err, "Ack")
+		return
+	}
+	return
+}
+
+// MarshalMsg implements msgp.Marshaler
+func (z AckResp) MarshalMsg(b []byte) (o []byte, err error) {
+	o = msgp.Require(b, z.Msgsize())
+	// map header, size 1
+	// string "ack"
+	o = append(o, 0x81, 0xa3, 0x61, 0x63, 0x6b)
+	o = msgp.AppendString(o, z.Ack)
+	return
+}
+
+// UnmarshalMsg implements msgp.Unmarshaler
+func (z *AckResp) UnmarshalMsg(bts []byte) (o []byte, err error) {
+	var field []byte
+	_ = field
+	var zb0001 uint32
+	zb0001, bts, err = msgp.ReadMapHeaderBytes(bts)
+	if err != nil {
+		err = msgp.WrapError(err)
+		return
+	}
+	for zb0001 > 0 {
+		zb0001--
+		field, bts, err = msgp.ReadMapKeyZC(bts)
+		if err != nil {
+			err = msgp.WrapError(err)
+			return
+		}
+		switch msgp.UnsafeString(field) {
+		case "ack":
+			z.Ack, bts, err = msgp.ReadStringBytes(bts)
+			if err != nil {
+				err = msgp.WrapError(err, "Ack")
+				return
+			}
+		default:
+			bts, err = msgp.Skip(bts)
+			if err != nil {
+				err = msgp.WrapError(err)
+				return
+			}
+		}
+	}
+	o = bts
+	return
+}
+
+// Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
+func (z AckResp) Msgsize() (s int) {
+	s = 1 + 4 + msgp.StringPrefixSize + len(z.Ack)
+	return
+}
+
+// DecodeMsg implements msgp.Decodable
+func (z *Entry) DecodeMsg(dc *msgp.Reader) (err error) {
+	var zb0001 uint32
+	zb0001, err = dc.ReadArrayHeader()
+	if err != nil {
+		err = msgp.WrapError(err)
+		return
+	}
+	if zb0001 != 2 {
+		err = msgp.ArrayError{Wanted: 2, Got: zb0001}
 		return
 	}
 	z.Time, err = dc.ReadInt64()
 	if err != nil {
+		err = msgp.WrapError(err, "Time")
 		return
 	}
 	z.Record, err = dc.ReadIntf()
 	if err != nil {
+		err = msgp.WrapError(err, "Record")
 		return
 	}
 	return
@@ -35,14 +139,16 @@ func (z Entry) EncodeMsg(en *msgp.Writer) (err error) {
 	// array header, size 2
 	err = en.Append(0x92)
 	if err != nil {
-		return err
+		return
 	}
 	err = en.WriteInt64(z.Time)
 	if err != nil {
+		err = msgp.WrapError(err, "Time")
 		return
 	}
 	err = en.WriteIntf(z.Record)
 	if err != nil {
+		err = msgp.WrapError(err, "Record")
 		return
 	}
 	return
@@ -56,6 +162,7 @@ func (z Entry) MarshalMsg(b []byte) (o []byte, err error) {
 	o = msgp.AppendInt64(o, z.Time)
 	o, err = msgp.AppendIntf(o, z.Record)
 	if err != nil {
+		err = msgp.WrapError(err, "Record")
 		return
 	}
 	return
@@ -63,21 +170,24 @@ func (z Entry) MarshalMsg(b []byte) (o []byte, err error) {
 
 // UnmarshalMsg implements msgp.Unmarshaler
 func (z *Entry) UnmarshalMsg(bts []byte) (o []byte, err error) {
-	var zbzg uint32
-	zbzg, bts, err = msgp.ReadArrayHeaderBytes(bts)
+	var zb0001 uint32
+	zb0001, bts, err = msgp.ReadArrayHeaderBytes(bts)
 	if err != nil {
+		err = msgp.WrapError(err)
 		return
 	}
-	if zbzg != 2 {
-		err = msgp.ArrayError{Wanted: 2, Got: zbzg}
+	if zb0001 != 2 {
+		err = msgp.ArrayError{Wanted: 2, Got: zb0001}
 		return
 	}
 	z.Time, bts, err = msgp.ReadInt64Bytes(bts)
 	if err != nil {
+		err = msgp.WrapError(err, "Time")
 		return
 	}
 	z.Record, bts, err = msgp.ReadIntfBytes(bts)
 	if err != nil {
+		err = msgp.WrapError(err, "Record")
 		return
 	}
 	o = bts
@@ -92,52 +202,83 @@ func (z Entry) Msgsize() (s int) {
 
 // DecodeMsg implements msgp.Decodable
 func (z *Forward) DecodeMsg(dc *msgp.Reader) (err error) {
-	var zcmr uint32
-	zcmr, err = dc.ReadArrayHeader()
+	var zb0001 uint32
+	zb0001, err = dc.ReadArrayHeader()
 	if err != nil {
+		err = msgp.WrapError(err)
 		return
 	}
-	if zcmr != 3 {
-		err = msgp.ArrayError{Wanted: 3, Got: zcmr}
+	if zb0001 != 3 {
+		err = msgp.ArrayError{Wanted: 3, Got: zb0001}
 		return
 	}
 	z.Tag, err = dc.ReadString()
 	if err != nil {
+		err = msgp.WrapError(err, "Tag")
 		return
 	}
-	var zajw uint32
-	zajw, err = dc.ReadArrayHeader()
+	var zb0002 uint32
+	zb0002, err = dc.ReadArrayHeader()
 	if err != nil {
+		err = msgp.WrapError(err, "Entries")
 		return
 	}
-	if cap(z.Entries) >= int(zajw) {
-		z.Entries = (z.Entries)[:zajw]
+	if cap(z.Entries) >= int(zb0002) {
+		z.Entries = (z.Entries)[:zb0002]
 	} else {
-		z.Entries = make([]Entry, zajw)
+		z.Entries = make([]Entry, zb0002)
 	}
-	for zbai := range z.Entries {
-		var zwht uint32
-		zwht, err = dc.ReadArrayHeader()
+	for za0001 := range z.Entries {
+		var zb0003 uint32
+		zb0003, err = dc.ReadArrayHeader()
 		if err != nil {
+			err = msgp.WrapError(err, "Entries", za0001)
 			return
 		}
-		if zwht != 2 {
-			err = msgp.ArrayError{Wanted: 2, Got: zwht}
+		if zb0003 != 2 {
+			err = msgp.ArrayError{Wanted: 2, Got: zb0003}
 			return
 		}
-		z.Entries[zbai].Time, err = dc.ReadInt64()
+		z.Entries[za0001].Time, err = dc.ReadInt64()
 		if err != nil {
+			err = msgp.WrapError(err, "Entries", za0001, "Time")
 			return
 		}
-		z.Entries[zbai].Record, err = dc.ReadIntf()
+		z.Entries[za0001].Record, err = dc.ReadIntf()
 		if err != nil {
+			err = msgp.WrapError(err, "Entries", za0001, "Record")
 			return
 		}
 	}
-	z.Option, err = dc.ReadIntf()
+	var zb0004 uint32
+	zb0004, err = dc.ReadMapHeader()
 	if err != nil {
+		err = msgp.WrapError(err, "Option")
 		return
 	}
+	if z.Option == nil {
+		z.Option = make(map[string]string, zb0004)
+	} else if len(z.Option) > 0 {
+		for key := range z.Option {
+			delete(z.Option, key)
+		}
+	}
+	for zb0004 > 0 {
+		zb0004--
+		var za0002 string
+		var za0003 string
+		za0002, err = dc.ReadString()
+		if err != nil {
+			err = msgp.WrapError(err, "Option")
+			return
+		}
+		za0003, err = dc.ReadString()
+		if err != nil {
+			err = msgp.WrapError(err, "Option", za0002)
+			return
+		}
+		z.Option[za0002] = za0003
+	}
 	return
 }
 
@@ -146,35 +287,52 @@ func (z *Forward) EncodeMsg(en *msgp.Writer) (err error) {
 	// array header, size 3
 	err = en.Append(0x93)
 	if err != nil {
-		return err
+		return
 	}
 	err = en.WriteString(z.Tag)
 	if err != nil {
+		err = msgp.WrapError(err, "Tag")
 		return
 	}
 	err = en.WriteArrayHeader(uint32(len(z.Entries)))
 	if err != nil {
+		err = msgp.WrapError(err, "Entries")
 		return
 	}
-	for zbai := range z.Entries {
+	for za0001 := range z.Entries {
 		// array header, size 2
 		err = en.Append(0x92)
-		if err != nil {
-			return err
-		}
-		err = en.WriteInt64(z.Entries[zbai].Time)
 		if err != nil {
 			return
 		}
-		err = en.WriteIntf(z.Entries[zbai].Record)
+		err = en.WriteInt64(z.Entries[za0001].Time)
 		if err != nil {
+			err = msgp.WrapError(err, "Entries", za0001, "Time")
+			return
+		}
+		err = en.WriteIntf(z.Entries[za0001].Record)
+		if err != nil {
+			err = msgp.WrapError(err, "Entries", za0001, "Record")
 			return
 		}
 	}
-	err = en.WriteIntf(z.Option)
+	err = en.WriteMapHeader(uint32(len(z.Option)))
 	if err != nil {
+		err = msgp.WrapError(err, "Option")
 		return
 	}
+	for za0002, za0003 := range z.Option {
+		err = en.WriteString(za0002)
+		if err != nil {
+			err = msgp.WrapError(err, "Option")
+			return
+		}
+		err = en.WriteString(za0003)
+		if err != nil {
+			err = msgp.WrapError(err, "Option", za0002)
+			return
+		}
+	}
 	return
 }
 
@@ -185,70 +343,103 @@ func (z *Forward) MarshalMsg(b []byte) (o []byte, err error) {
 	o = append(o, 0x93)
 	o = msgp.AppendString(o, z.Tag)
 	o = msgp.AppendArrayHeader(o, uint32(len(z.Entries)))
-	for zbai := range z.Entries {
+	for za0001 := range z.Entries {
 		// array header, size 2
 		o = append(o, 0x92)
-		o = msgp.AppendInt64(o, z.Entries[zbai].Time)
-		o, err = msgp.AppendIntf(o, z.Entries[zbai].Record)
+		o = msgp.AppendInt64(o, z.Entries[za0001].Time)
+		o, err = msgp.AppendIntf(o, z.Entries[za0001].Record)
 		if err != nil {
+			err = msgp.WrapError(err, "Entries", za0001, "Record")
 			return
 		}
 	}
-	o, err = msgp.AppendIntf(o, z.Option)
-	if err != nil {
-		return
+	o = msgp.AppendMapHeader(o, uint32(len(z.Option)))
+	for za0002, za0003 := range z.Option {
+		o = msgp.AppendString(o, za0002)
+		o = msgp.AppendString(o, za0003)
 	}
 	return
 }
 
 // UnmarshalMsg implements msgp.Unmarshaler
 func (z *Forward) UnmarshalMsg(bts []byte) (o []byte, err error) {
-	var zhct uint32
-	zhct, bts, err = msgp.ReadArrayHeaderBytes(bts)
+	var zb0001 uint32
+	zb0001, bts, err = msgp.ReadArrayHeaderBytes(bts)
 	if err != nil {
+		err = msgp.WrapError(err)
 		return
 	}
-	if zhct != 3 {
-		err = msgp.ArrayError{Wanted: 3, Got: zhct}
+	if zb0001 != 3 {
+		err = msgp.ArrayError{Wanted: 3, Got: zb0001}
 		return
 	}
 	z.Tag, bts, err = msgp.ReadStringBytes(bts)
 	if err != nil {
+		err = msgp.WrapError(err, "Tag")
 		return
 	}
-	var zcua uint32
-	zcua, bts, err = msgp.ReadArrayHeaderBytes(bts)
+	var zb0002 uint32
+	zb0002, bts, err = msgp.ReadArrayHeaderBytes(bts)
 	if err != nil {
+		err = msgp.WrapError(err, "Entries")
 		return
 	}
-	if cap(z.Entries) >= int(zcua) {
-		z.Entries = (z.Entries)[:zcua]
+	if cap(z.Entries) >= int(zb0002) {
+		z.Entries = (z.Entries)[:zb0002]
 	} else {
-		z.Entries = make([]Entry, zcua)
+		z.Entries = make([]Entry, zb0002)
 	}
-	for zbai := range z.Entries {
-		var zxhx uint32
-		zxhx, bts, err = msgp.ReadArrayHeaderBytes(bts)
+	for za0001 := range z.Entries {
+		var zb0003 uint32
+		zb0003, bts, err = msgp.ReadArrayHeaderBytes(bts)
 		if err != nil {
+			err = msgp.WrapError(err, "Entries", za0001)
 			return
 		}
-		if zxhx != 2 {
-			err = msgp.ArrayError{Wanted: 2, Got: zxhx}
+		if zb0003 != 2 {
+			err = msgp.ArrayError{Wanted: 2, Got: zb0003}
 			return
 		}
-		z.Entries[zbai].Time, bts, err = msgp.ReadInt64Bytes(bts)
+		z.Entries[za0001].Time, bts, err = msgp.ReadInt64Bytes(bts)
 		if err != nil {
+			err = msgp.WrapError(err, "Entries", za0001, "Time")
 			return
 		}
-		z.Entries[zbai].Record, bts, err = msgp.ReadIntfBytes(bts)
+		z.Entries[za0001].Record, bts, err = msgp.ReadIntfBytes(bts)
 		if err != nil {
+			err = msgp.WrapError(err, "Entries", za0001, "Record")
 			return
 		}
 	}
-	z.Option, bts, err = msgp.ReadIntfBytes(bts)
+	var zb0004 uint32
+	zb0004, bts, err = msgp.ReadMapHeaderBytes(bts)
 	if err != nil {
+		err = msgp.WrapError(err, "Option")
 		return
 	}
+	if z.Option == nil {
+		z.Option = make(map[string]string, zb0004)
+	} else if len(z.Option) > 0 {
+		for key := range z.Option {
+			delete(z.Option, key)
+		}
+	}
+	for zb0004 > 0 {
+		var za0002 string
+		var za0003 string
+		zb0004--
+		za0002, bts, err = msgp.ReadStringBytes(bts)
+		if err != nil {
+			err = msgp.WrapError(err, "Option")
+			return
+		}
+		za0003, bts, err = msgp.ReadStringBytes(bts)
+		if err != nil {
+			err = msgp.WrapError(err, "Option", za0002)
+			return
+		}
+		z.Option[za0002] = za0003
+	}
 	o = bts
 	return
 }
@@ -256,40 +447,75 @@ func (z *Forward) UnmarshalMsg(bts []byte) (o []byte, err error) {
 // Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
 func (z *Forward) Msgsize() (s int) {
 	s = 1 + msgp.StringPrefixSize + len(z.Tag) + msgp.ArrayHeaderSize
-	for zbai := range z.Entries {
-		s += 1 + msgp.Int64Size + msgp.GuessSize(z.Entries[zbai].Record)
+	for za0001 := range z.Entries {
+		s += 1 + msgp.Int64Size + msgp.GuessSize(z.Entries[za0001].Record)
+	}
+	s += msgp.MapHeaderSize
+	if z.Option != nil {
+		for za0002, za0003 := range z.Option {
+			_ = za0003
+			s += msgp.StringPrefixSize + len(za0002) + msgp.StringPrefixSize + len(za0003)
+		}
 	}
-	s += msgp.GuessSize(z.Option)
 	return
 }
 
 // DecodeMsg implements msgp.Decodable
 func (z *Message) DecodeMsg(dc *msgp.Reader) (err error) {
-	var zlqf uint32
-	zlqf, err = dc.ReadArrayHeader()
+	var zb0001 uint32
+	zb0001, err = dc.ReadArrayHeader()
 	if err != nil {
+		err = msgp.WrapError(err)
 		return
 	}
-	if zlqf != 4 {
-		err = msgp.ArrayError{Wanted: 4, Got: zlqf}
+	if zb0001 != 4 {
+		err = msgp.ArrayError{Wanted: 4, Got: zb0001}
 		return
 	}
 	z.Tag, err = dc.ReadString()
 	if err != nil {
+		err = msgp.WrapError(err, "Tag")
 		return
 	}
 	z.Time, err = dc.ReadInt64()
 	if err != nil {
+		err = msgp.WrapError(err, "Time")
 		return
 	}
 	z.Record, err = dc.ReadIntf()
 	if err != nil {
+		err = msgp.WrapError(err, "Record")
 		return
 	}
-	z.Option, err = dc.ReadIntf()
+	var zb0002 uint32
+	zb0002, err = dc.ReadMapHeader()
 	if err != nil {
+		err = msgp.WrapError(err, "Option")
 		return
 	}
+	if z.Option == nil {
+		z.Option = make(map[string]string, zb0002)
+	} else if len(z.Option) > 0 {
+		for key := range z.Option {
+			delete(z.Option, key)
+		}
+	}
+	for zb0002 > 0 {
+		zb0002--
+		var za0001 string
+		var za0002 string
+		za0001, err = dc.ReadString()
+		if err != nil {
+			err = msgp.WrapError(err, "Option")
+			return
+		}
+		za0002, err = dc.ReadString()
+		if err != nil {
+			err = msgp.WrapError(err, "Option", za0001)
+			return
+		}
+		z.Option[za0001] = za0002
+	}
 	return
 }
 
@@ -298,24 +524,40 @@ func (z *Message) EncodeMsg(en *msgp.Writer) (err error) {
 	// array header, size 4
 	err = en.Append(0x94)
 	if err != nil {
-		return err
+		return
 	}
 	err = en.WriteString(z.Tag)
 	if err != nil {
+		err = msgp.WrapError(err, "Tag")
 		return
 	}
 	err = en.WriteInt64(z.Time)
 	if err != nil {
+		err = msgp.WrapError(err, "Time")
 		return
 	}
 	err = en.WriteIntf(z.Record)
 	if err != nil {
+		err = msgp.WrapError(err, "Record")
 		return
 	}
-	err = en.WriteIntf(z.Option)
+	err = en.WriteMapHeader(uint32(len(z.Option)))
 	if err != nil {
+		err = msgp.WrapError(err, "Option")
 		return
 	}
+	for za0001, za0002 := range z.Option {
+		err = en.WriteString(za0001)
+		if err != nil {
+			err = msgp.WrapError(err, "Option")
+			return
+		}
+		err = en.WriteString(za0002)
+		if err != nil {
+			err = msgp.WrapError(err, "Option", za0001)
+			return
+		}
+	}
 	return
 }
 
@@ -328,79 +570,145 @@ func (z *Message) MarshalMsg(b []byte) (o []byte, err error) {
 	o = msgp.AppendInt64(o, z.Time)
 	o, err = msgp.AppendIntf(o, z.Record)
 	if err != nil {
+		err = msgp.WrapError(err, "Record")
 		return
 	}
-	o, err = msgp.AppendIntf(o, z.Option)
-	if err != nil {
-		return
+	o = msgp.AppendMapHeader(o, uint32(len(z.Option)))
+	for za0001, za0002 := range z.Option {
+		o = msgp.AppendString(o, za0001)
+		o = msgp.AppendString(o, za0002)
 	}
 	return
 }
 
 // UnmarshalMsg implements msgp.Unmarshaler
 func (z *Message) UnmarshalMsg(bts []byte) (o []byte, err error) {
-	var zdaf uint32
-	zdaf, bts, err = msgp.ReadArrayHeaderBytes(bts)
+	var zb0001 uint32
+	zb0001, bts, err = msgp.ReadArrayHeaderBytes(bts)
 	if err != nil {
+		err = msgp.WrapError(err)
 		return
 	}
-	if zdaf != 4 {
-		err = msgp.ArrayError{Wanted: 4, Got: zdaf}
+	if zb0001 != 4 {
+		err = msgp.ArrayError{Wanted: 4, Got: zb0001}
 		return
 	}
 	z.Tag, bts, err = msgp.ReadStringBytes(bts)
 	if err != nil {
+		err = msgp.WrapError(err, "Tag")
 		return
 	}
 	z.Time, bts, err = msgp.ReadInt64Bytes(bts)
 	if err != nil {
+		err = msgp.WrapError(err, "Time")
 		return
 	}
 	z.Record, bts, err = msgp.ReadIntfBytes(bts)
 	if err != nil {
+		err = msgp.WrapError(err, "Record")
 		return
 	}
-	z.Option, bts, err = msgp.ReadIntfBytes(bts)
+	var zb0002 uint32
+	zb0002, bts, err = msgp.ReadMapHeaderBytes(bts)
 	if err != nil {
+		err = msgp.WrapError(err, "Option")
 		return
 	}
+	if z.Option == nil {
+		z.Option = make(map[string]string, zb0002)
+	} else if len(z.Option) > 0 {
+		for key := range z.Option {
+			delete(z.Option, key)
+		}
+	}
+	for zb0002 > 0 {
+		var za0001 string
+		var za0002 string
+		zb0002--
+		za0001, bts, err = msgp.ReadStringBytes(bts)
+		if err != nil {
+			err = msgp.WrapError(err, "Option")
+			return
+		}
+		za0002, bts, err = msgp.ReadStringBytes(bts)
+		if err != nil {
+			err = msgp.WrapError(err, "Option", za0001)
+			return
+		}
+		z.Option[za0001] = za0002
+	}
 	o = bts
 	return
 }
 
 // Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
 func (z *Message) Msgsize() (s int) {
-	s = 1 + msgp.StringPrefixSize + len(z.Tag) + msgp.Int64Size + msgp.GuessSize(z.Record) + msgp.GuessSize(z.Option)
+	s = 1 + msgp.StringPrefixSize + len(z.Tag) + msgp.Int64Size + msgp.GuessSize(z.Record) + msgp.MapHeaderSize
+	if z.Option != nil {
+		for za0001, za0002 := range z.Option {
+			_ = za0002
+			s += msgp.StringPrefixSize + len(za0001) + msgp.StringPrefixSize + len(za0002)
+		}
+	}
 	return
 }
 
 // DecodeMsg implements msgp.Decodable
 func (z *MessageExt) DecodeMsg(dc *msgp.Reader) (err error) {
-	var zpks uint32
-	zpks, err = dc.ReadArrayHeader()
+	var zb0001 uint32
+	zb0001, err = dc.ReadArrayHeader()
 	if err != nil {
+		err = msgp.WrapError(err)
 		return
 	}
-	if zpks != 4 {
-		err = msgp.ArrayError{Wanted: 4, Got: zpks}
+	if zb0001 != 4 {
+		err = msgp.ArrayError{Wanted: 4, Got: zb0001}
 		return
 	}
 	z.Tag, err = dc.ReadString()
 	if err != nil {
+		err = msgp.WrapError(err, "Tag")
 		return
 	}
 	err = dc.ReadExtension(&z.Time)
 	if err != nil {
+		err = msgp.WrapError(err, "Time")
 		return
 	}
 	z.Record, err = dc.ReadIntf()
 	if err != nil {
+		err = msgp.WrapError(err, "Record")
 		return
 	}
-	z.Option, err = dc.ReadIntf()
+	var zb0002 uint32
+	zb0002, err = dc.ReadMapHeader()
 	if err != nil {
+		err = msgp.WrapError(err, "Option")
 		return
 	}
+	if z.Option == nil {
+		z.Option = make(map[string]string, zb0002)
+	} else if len(z.Option) > 0 {
+		for key := range z.Option {
+			delete(z.Option, key)
+		}
+	}
+	for zb0002 > 0 {
+		zb0002--
+		var za0001 string
+		var za0002 string
+		za0001, err = dc.ReadString()
+		if err != nil {
+			err = msgp.WrapError(err, "Option")
+			return
+		}
+		za0002, err = dc.ReadString()
+		if err != nil {
+			err = msgp.WrapError(err, "Option", za0001)
+			return
+		}
+		z.Option[za0001] = za0002
+	}
 	return
 }
 
@@ -409,24 +717,40 @@ func (z *MessageExt) EncodeMsg(en *msgp.Writer) (err error) {
 	// array header, size 4
 	err = en.Append(0x94)
 	if err != nil {
-		return err
+		return
 	}
 	err = en.WriteString(z.Tag)
 	if err != nil {
+		err = msgp.WrapError(err, "Tag")
 		return
 	}
 	err = en.WriteExtension(&z.Time)
 	if err != nil {
+		err = msgp.WrapError(err, "Time")
 		return
 	}
 	err = en.WriteIntf(z.Record)
 	if err != nil {
+		err = msgp.WrapError(err, "Record")
 		return
 	}
-	err = en.WriteIntf(z.Option)
+	err = en.WriteMapHeader(uint32(len(z.Option)))
 	if err != nil {
+		err = msgp.WrapError(err, "Option")
 		return
 	}
+	for za0001, za0002 := range z.Option {
+		err = en.WriteString(za0001)
+		if err != nil {
+			err = msgp.WrapError(err, "Option")
+			return
+		}
+		err = en.WriteString(za0002)
+		if err != nil {
+			err = msgp.WrapError(err, "Option", za0001)
+			return
+		}
+	}
 	return
 }
 
@@ -438,52 +762,90 @@ func (z *MessageExt) MarshalMsg(b []byte) (o []byte, err error) {
 	o = msgp.AppendString(o, z.Tag)
 	o, err = msgp.AppendExtension(o, &z.Time)
 	if err != nil {
+		err = msgp.WrapError(err, "Time")
 		return
 	}
 	o, err = msgp.AppendIntf(o, z.Record)
 	if err != nil {
+		err = msgp.WrapError(err, "Record")
 		return
 	}
-	o, err = msgp.AppendIntf(o, z.Option)
-	if err != nil {
-		return
+	o = msgp.AppendMapHeader(o, uint32(len(z.Option)))
+	for za0001, za0002 := range z.Option {
+		o = msgp.AppendString(o, za0001)
+		o = msgp.AppendString(o, za0002)
 	}
 	return
 }
 
 // UnmarshalMsg implements msgp.Unmarshaler
 func (z *MessageExt) UnmarshalMsg(bts []byte) (o []byte, err error) {
-	var zjfb uint32
-	zjfb, bts, err = msgp.ReadArrayHeaderBytes(bts)
+	var zb0001 uint32
+	zb0001, bts, err = msgp.ReadArrayHeaderBytes(bts)
 	if err != nil {
+		err = msgp.WrapError(err)
 		return
 	}
-	if zjfb != 4 {
-		err = msgp.ArrayError{Wanted: 4, Got: zjfb}
+	if zb0001 != 4 {
+		err = msgp.ArrayError{Wanted: 4, Got: zb0001}
 		return
 	}
 	z.Tag, bts, err = msgp.ReadStringBytes(bts)
 	if err != nil {
+		err = msgp.WrapError(err, "Tag")
 		return
 	}
 	bts, err = msgp.ReadExtensionBytes(bts, &z.Time)
 	if err != nil {
+		err = msgp.WrapError(err, "Time")
 		return
 	}
 	z.Record, bts, err = msgp.ReadIntfBytes(bts)
 	if err != nil {
+		err = msgp.WrapError(err, "Record")
 		return
 	}
-	z.Option, bts, err = msgp.ReadIntfBytes(bts)
+	var zb0002 uint32
+	zb0002, bts, err = msgp.ReadMapHeaderBytes(bts)
 	if err != nil {
+		err = msgp.WrapError(err, "Option")
 		return
 	}
+	if z.Option == nil {
+		z.Option = make(map[string]string, zb0002)
+	} else if len(z.Option) > 0 {
+		for key := range z.Option {
+			delete(z.Option, key)
+		}
+	}
+	for zb0002 > 0 {
+		var za0001 string
+		var za0002 string
+		zb0002--
+		za0001, bts, err = msgp.ReadStringBytes(bts)
+		if err != nil {
+			err = msgp.WrapError(err, "Option")
+			return
+		}
+		za0002, bts, err = msgp.ReadStringBytes(bts)
+		if err != nil {
+			err = msgp.WrapError(err, "Option", za0001)
+			return
+		}
+		z.Option[za0001] = za0002
+	}
 	o = bts
 	return
 }
 
 // Msgsize returns an upper bound estimate of the number of bytes occupied by the serialized message
 func (z *MessageExt) Msgsize() (s int) {
-	s = 1 + msgp.StringPrefixSize + len(z.Tag) + msgp.ExtensionPrefixSize + z.Time.Len() + msgp.GuessSize(z.Record) + msgp.GuessSize(z.Option)
+	s = 1 + msgp.StringPrefixSize + len(z.Tag) + msgp.ExtensionPrefixSize + z.Time.Len() + msgp.GuessSize(z.Record) + msgp.MapHeaderSize
+	if z.Option != nil {
+		for za0001, za0002 := range z.Option {
+			_ = za0002
+			s += msgp.StringPrefixSize + len(za0001) + msgp.StringPrefixSize + len(za0002)
+		}
+	}
 	return
 }

vendor/github.com/fluent/fluent-logger-golang/fluent/test_message_gen.go

@@ -1,8 +1,6 @@
 package fluent
 
-// NOTE: THIS FILE WAS PRODUCED BY THE
-// MSGP CODE GENERATION TOOL (github.com/tinylib/msgp)
-// DO NOT EDIT
+// Code generated by github.com/tinylib/msgp DO NOT EDIT.
 
 import (
 	"github.com/tinylib/msgp/msgp"
@@ -12,31 +10,36 @@ import (
 func (z *TestMessage) DecodeMsg(dc *msgp.Reader) (err error) {
 	var field []byte
 	_ = field
-	var zxvk uint32
-	zxvk, err = dc.ReadMapHeader()
+	var zb0001 uint32
+	zb0001, err = dc.ReadMapHeader()
 	if err != nil {
+		err = msgp.WrapError(err)
 		return
 	}
-	for zxvk > 0 {
-		zxvk--
+	for zb0001 > 0 {
+		zb0001--
 		field, err = dc.ReadMapKeyPtr()
 		if err != nil {
+			err = msgp.WrapError(err)
 			return
 		}
 		switch msgp.UnsafeString(field) {
 		case "foo":
 			z.Foo, err = dc.ReadString()
 			if err != nil {
+				err = msgp.WrapError(err, "Foo")
 				return
 			}
 		case "hoge":
 			z.Hoge, err = dc.ReadString()
 			if err != nil {
+				err = msgp.WrapError(err, "Hoge")
 				return
 			}
 		default:
 			err = dc.Skip()
 			if err != nil {
+				err = msgp.WrapError(err)
 				return
 			}
 		}
@@ -50,19 +53,21 @@ func (z TestMessage) EncodeMsg(en *msgp.Writer) (err error) {
 	// write "foo"
 	err = en.Append(0x82, 0xa3, 0x66, 0x6f, 0x6f)
 	if err != nil {
-		return err
+		return
 	}
 	err = en.WriteString(z.Foo)
 	if err != nil {
+		err = msgp.WrapError(err, "Foo")
 		return
 	}
 	// write "hoge"
 	err = en.Append(0xa4, 0x68, 0x6f, 0x67, 0x65)
 	if err != nil {
-		return err
+		return
 	}
 	err = en.WriteString(z.Hoge)
 	if err != nil {
+		err = msgp.WrapError(err, "Hoge")
 		return
 	}
 	return
@@ -85,31 +90,36 @@ func (z TestMessage) MarshalMsg(b []byte) (o []byte, err error) {
 func (z *TestMessage) UnmarshalMsg(bts []byte) (o []byte, err error) {
 	var field []byte
 	_ = field
-	var zbzg uint32
-	zbzg, bts, err = msgp.ReadMapHeaderBytes(bts)
+	var zb0001 uint32
+	zb0001, bts, err = msgp.ReadMapHeaderBytes(bts)
 	if err != nil {
+		err = msgp.WrapError(err)
 		return
 	}
-	for zbzg > 0 {
-		zbzg--
+	for zb0001 > 0 {
+		zb0001--
 		field, bts, err = msgp.ReadMapKeyZC(bts)
 		if err != nil {
+			err = msgp.WrapError(err)
 			return
 		}
 		switch msgp.UnsafeString(field) {
 		case "foo":
 			z.Foo, bts, err = msgp.ReadStringBytes(bts)
 			if err != nil {
+				err = msgp.WrapError(err, "Foo")
 				return
 			}
 		case "hoge":
 			z.Hoge, bts, err = msgp.ReadStringBytes(bts)
 			if err != nil {
+				err = msgp.WrapError(err, "Hoge")
 				return
 			}
 		default:
 			bts, err = msgp.Skip(bts)
 			if err != nil {
+				err = msgp.WrapError(err)
 				return
 			}
 		}

vendor/github.com/fluent/fluent-logger-golang/fluent/version.go

@@ -1,3 +1,3 @@
 package fluent
 
-const Version = "1.3.0"
+const Version = "1.4.0"