fix tests, update for logging

core/healthcheck/processor_test.go

@@ -45,7 +45,7 @@ func (t *CounterProcessorTest) localizer() NotifyMessageLocalizer {
 }
 
 func (t *CounterProcessorTest) new(
-	nf NotifyFunc, pr ConnectionDataProvider, noLocalizer ...bool) (Processor, testutil.BufferedLogger) {
+	nf NotifyFunc, pr ConnectionDataProvider, noLocalizer ...bool) (Processor, *testutil.JSONRecordScanner) {
 	loc := t.localizer()
 	if len(noLocalizer) > 0 && noLocalizer[0] {
 		loc = nil
@@ -61,7 +61,7 @@ func (t *CounterProcessorTest) new(
 		FailureThreshold:       DefaultFailureThreshold,
 		MinRequests:            DefaultMinRequests,
 		Debug:                  true,
-	}, log
+	}, testutil.NewJSONRecordScanner(log)
 }
 
 func (t *CounterProcessorTest) notifier(err ...error) *notifierMock {
@@ -95,8 +95,12 @@ func (t *CounterProcessorTest) Test_FailureProcessed() {
 
 	p.Process(1, c)
 	c.AssertExpectations(t.T())
-	t.Assert().Contains(log.String(), "skipping counter because its failure is already processed")
+
-	t.Assert().Contains(log.String(), `"counterId": 1`)
+	logs, err := log.ScanAll()
+	t.Require().NoError(err)
+	t.Require().Len(logs, 1)
+	t.Assert().Contains(logs[0].Message, "skipping counter because its failure is already processed")
+	t.Assert().Equal(float64(1), logs[0].Context["counterId"])
 }
 
 func (t *CounterProcessorTest) Test_CounterFailed_CannotFindConnection() {
@@ -108,8 +112,12 @@ func (t *CounterProcessorTest) Test_CounterFailed_CannotFindConnection() {
 
 	p.Process(1, c)
 	c.AssertExpectations(t.T())
-	t.Assert().Contains(log.String(), "cannot find connection data for counter")
+
-	t.Assert().Contains(log.String(), `"counterId": 1`)
+	logs, err := log.ScanAll()
+	t.Require().NoError(err)
+	t.Require().Len(logs, 1)
+	t.Assert().Contains(logs[0].Message, "cannot find connection data for counter")
+	t.Assert().Equal(float64(1), logs[0].Context["counterId"])
 }
 
 func (t *CounterProcessorTest) Test_CounterFailed_ErrWhileNotifying() {
@@ -123,10 +131,14 @@ func (t *CounterProcessorTest) Test_CounterFailed_ErrWhileNotifying() {
 
 	p.Process(1, c)
 	c.AssertExpectations(t.T())
-	t.Assert().Contains(log.String(), "cannot send notification for counter")
+
-	t.Assert().Contains(log.String(), `"counterId": 1`)
+	logs, err := log.ScanAll()
-	t.Assert().Contains(log.String(), `"error": "http status code: 500"`)
+	t.Require().NoError(err)
-	t.Assert().Contains(log.String(), `"failureMessage": "error message"`)
+	t.Require().Len(logs, 1)
+	t.Assert().Contains(logs[0].Message, "cannot send notification for counter")
+	t.Assert().Equal(float64(1), logs[0].Context["counterId"])
+	t.Assert().Equal("http status code: 500", logs[0].Context["error"])
+	t.Assert().Equal("error message", logs[0].Context["failureMessage"])
 	t.Assert().Equal(t.apiURL, n.apiURL)
 	t.Assert().Equal(t.apiKey, n.apiKey)
 	t.Assert().Equal("error message", n.message)
@@ -143,7 +155,10 @@ func (t *CounterProcessorTest) Test_CounterFailed_SentNotification() {
 
 	p.Process(1, c)
 	c.AssertExpectations(t.T())
-	t.Assert().Empty(log.String())
+
+	logs, err := log.ScanAll()
+	t.Require().NoError(err)
+	t.Require().Len(logs, 0)
 	t.Assert().Equal(t.apiURL, n.apiURL)
 	t.Assert().Equal(t.apiKey, n.apiKey)
 	t.Assert().Equal("error message", n.message)
@@ -159,8 +174,13 @@ func (t *CounterProcessorTest) Test_TooFewRequests() {
 
 	p.Process(1, c)
 	c.AssertExpectations(t.T())
-	t.Assert().Contains(log.String(),
+
-		fmt.Sprintf(`skipping counter because it has too few requests {"counterId": %d, "minRequests": %d}`, 1, DefaultMinRequests))
+	logs, err := log.ScanAll()
+	t.Require().NoError(err)
+	t.Require().Len(logs, 1)
+	t.Assert().Contains(logs[0].Message, "skipping counter because it has too few requests")
+	t.Assert().Equal(float64(1), logs[0].Context["counterId"])
+	t.Assert().Equal(float64(DefaultMinRequests), logs[0].Context["minRequests"])
 }
 
 func (t *CounterProcessorTest) Test_ThresholdNotPassed() {
@@ -175,7 +195,10 @@ func (t *CounterProcessorTest) Test_ThresholdNotPassed() {
 
 	p.Process(1, c)
 	c.AssertExpectations(t.T())
-	t.Assert().Empty(log.String())
+
+	logs, err := log.ScanAll()
+	t.Require().NoError(err)
+	t.Require().Len(logs, 0)
 	t.Assert().Empty(n.message)
 }
 
@@ -190,7 +213,10 @@ func (t *CounterProcessorTest) Test_ThresholdPassed_AlreadyProcessed() {
 
 	p.Process(1, c)
 	c.AssertExpectations(t.T())
-	t.Assert().Empty(log.String())
+
+	logs, err := log.ScanAll()
+	t.Require().NoError(err)
+	t.Require().Len(logs, 0)
 	t.Assert().Empty(n.message)
 }
 
@@ -205,8 +231,12 @@ func (t *CounterProcessorTest) Test_ThresholdPassed_NoConnectionFound() {
 
 	p.Process(1, c)
 	c.AssertExpectations(t.T())
-	t.Assert().Contains(log.String(), "cannot find connection data for counter")
+
-	t.Assert().Contains(log.String(), `"counterId": 1`)
+	logs, err := log.ScanAll()
+	t.Require().NoError(err)
+	t.Require().Len(logs, 1)
+	t.Assert().Contains(logs[0].Message, "cannot find connection data for counter")
+	t.Assert().Equal(float64(1), logs[0].Context["counterId"])
 	t.Assert().Empty(n.message)
 }
 
@@ -224,7 +254,13 @@ func (t *CounterProcessorTest) Test_ThresholdPassed_NotifyingError() {
 
 	p.Process(1, c)
 	c.AssertExpectations(t.T())
-	t.Assert().Contains(log.String(), `cannot send notification for counter {"counterId": 1, "error": "unknown error", "failureMessage": ""}`)
+
+	logs, err := log.ScanAll()
+	t.Require().NoError(err)
+	t.Require().Len(logs, 1)
+	t.Assert().Contains(logs[0].Message, "cannot send notification for counter")
+	t.Assert().Equal(float64(1), logs[0].Context["counterId"])
+	t.Assert().Equal("unknown error", logs[0].Context["error"])
 	t.Assert().Equal(`default error [{"Name":"MockedCounter"}]`, n.message)
 }
 
@@ -241,7 +277,10 @@ func (t *CounterProcessorTest) Test_ThresholdPassed_NotificationSent() {
 
 	p.Process(1, c)
 	c.AssertExpectations(t.T())
-	t.Assert().Empty(log.String())
+
+	logs, err := log.ScanAll()
+	t.Require().NoError(err)
+	t.Require().Len(logs, 0)
 	t.Assert().Equal(`default error [{"Name":"MockedCounter"}]`, n.message)
 }
 
@@ -258,7 +297,10 @@ func (t *CounterProcessorTest) Test_ThresholdPassed_NotificationSent_NoLocalizer
 
 	p.Process(1, c)
 	c.AssertExpectations(t.T())
-	t.Assert().Empty(log.String())
+
+	logs, err := log.ScanAll()
+	t.Require().NoError(err)
+	t.Require().Len(logs, 0)
 	t.Assert().Equal(`default error`, n.message)
 }
 

core/job_manager_test.go

@@ -436,7 +436,7 @@ func (t *JobManagerTest) WaitForJob() bool {
 
 func (t *JobManagerTest) Test_SetLogger() {
 	t.manager.logger = nil
-	t.manager.SetLogger(logger.NewDefault("console", true))
+	t.manager.SetLogger(logger.NewDefault("json", true))
 	assert.IsType(t.T(), &logger.Default{}, t.manager.logger)
 
 	t.manager.SetLogger(nil)

core/logger/api_client_adapter.go

@@ -2,10 +2,16 @@ package logger
 
 import (
 	"fmt"
+	"go.uber.org/zap"
 
 	retailcrm "github.com/retailcrm/api-client-go/v2"
 )
 
+const (
+	apiDebugLogReq  = "API Request: %s %s"
+	apiDebugLogResp = "API Response: %s"
+)
+
 type apiClientAdapter struct {
 	logger Logger
 }
@@ -17,5 +23,19 @@ func APIClientAdapter(logger Logger) retailcrm.BasicLogger {
 
 // Printf data in the log using Debug method.
 func (l *apiClientAdapter) Printf(format string, v ...interface{}) {
-	l.logger.Debug(fmt.Sprintf(format, v...))
+	switch format {
+	case apiDebugLogReq:
+		var url, key string
+		if len(v) > 0 {
+			url = fmt.Sprint(v[0])
+		}
+		if len(v) > 1 {
+			key = fmt.Sprint(v[1])
+		}
+		l.logger.Debug("API Request", zap.String("url", url), zap.String("key", key))
+	case apiDebugLogResp:
+		l.logger.Debug("API Response", Body(v[0]))
+	default:
+		l.logger.Debug(fmt.Sprintf(format, v...))
+	}
 }

core/logger/api_client_adapter_test.go

@@ -0,0 +1,40 @@
+package logger
+
+import (
+	"github.com/h2non/gock"
+	retailcrm "github.com/retailcrm/api-client-go/v2"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"net/http"
+	"testing"
+)
+
+func TestAPIClientAdapter(t *testing.T) {
+	log := newJSONBufferedLogger()
+	client := retailcrm.New("https://example.com", "test_key").WithLogger(APIClientAdapter(log.Logger()))
+	client.Debug = true
+
+	defer gock.Off()
+	gock.New("https://example.com").
+		Get("/api/credentials").
+		Reply(http.StatusOK).
+		JSON(retailcrm.CredentialResponse{Success: true})
+
+	_, _, err := client.APICredentials()
+	require.NoError(t, err)
+
+	entries, err := log.ScanAll()
+	require.NoError(t, err)
+	require.Len(t, entries, 2)
+
+	assert.Equal(t, "DEBUG", entries[0].LevelName)
+	assert.True(t, entries[0].DateTime.Valid)
+	assert.Equal(t, "API Request", entries[0].Message)
+	assert.Equal(t, "test_key", entries[0].Context["key"])
+	assert.Equal(t, "https://example.com/api/credentials", entries[0].Context["url"])
+
+	assert.Equal(t, "DEBUG", entries[1].LevelName)
+	assert.True(t, entries[1].DateTime.Valid)
+	assert.Equal(t, "API Response", entries[1].Message)
+	assert.Equal(t, map[string]interface{}{"success": true}, entries[1].Context["body"])
+}

core/logger/attrs.go

@@ -2,24 +2,44 @@ package logger
 
 import (
 	"fmt"
+	json "github.com/goccy/go-json"
+	"io"
 	"net/http"
 
 	"go.uber.org/zap"
 )
 
-const (
+// HandlerAttr represents the attribute name for the handler.
-	HandlerAttr        = "handler"
+const HandlerAttr = "handler"
-	ConnectionAttr     = "connection"
-	AccountAttr        = "account"
-	CounterIDAttr      = "counterId"
-	ErrorAttr          = "error"
-	FailureMessageAttr = "failureMessage"
-	BodyAttr           = "body"
-	HTTPMethodAttr     = "method"
-	HTTPStatusAttr     = "statusCode"
-	HTTPStatusNameAttr = "statusName"
-)
 
+// ConnectionAttr represents the attribute name for the connection.
+const ConnectionAttr = "connection"
+
+// AccountAttr represents the attribute name for the account.
+const AccountAttr = "account"
+
+// CounterIDAttr represents the attribute name for the counter ID.
+const CounterIDAttr = "counterId"
+
+// ErrorAttr represents the attribute name for an error.
+const ErrorAttr = "error"
+
+// FailureMessageAttr represents the attribute name for a failure message.
+const FailureMessageAttr = "failureMessage"
+
+// BodyAttr represents the attribute name for the request body.
+const BodyAttr = "body"
+
+// HTTPMethodAttr represents the attribute name for the HTTP method.
+const HTTPMethodAttr = "method"
+
+// HTTPStatusAttr represents the attribute name for the HTTP status code.
+const HTTPStatusAttr = "statusCode"
+
+// HTTPStatusNameAttr represents the attribute name for the HTTP status name.
+const HTTPStatusNameAttr = "statusName"
+
+// Err returns a zap.Field with the given error value.
 func Err(err any) zap.Field {
 	if err == nil {
 		return zap.String(ErrorAttr, "<nil>")
@@ -27,24 +47,46 @@ func Err(err any) zap.Field {
 	return zap.Any(ErrorAttr, err)
 }
 
+// Handler returns a zap.Field with the given handler name.
 func Handler(name string) zap.Field {
 	return zap.String(HandlerAttr, name)
 }
 
+// HTTPStatusCode returns a zap.Field with the given HTTP status code.
 func HTTPStatusCode(code int) zap.Field {
 	return zap.Int(HTTPStatusAttr, code)
 }
 
+// HTTPStatusName returns a zap.Field with the given HTTP status name.
 func HTTPStatusName(code int) zap.Field {
 	return zap.String(HTTPStatusNameAttr, http.StatusText(code))
 }
 
+// Body returns a zap.Field with the given request body value.
 func Body(val any) zap.Field {
 	switch item := val.(type) {
 	case string:
+		var m map[string]interface{}
+		if err := json.Unmarshal([]byte(item), &m); err == nil {
+			return zap.Any(BodyAttr, m)
+		}
 		return zap.String(BodyAttr, item)
 	case []byte:
+		var m interface{}
+		if err := json.Unmarshal(item, &m); err == nil {
+			return zap.Any(BodyAttr, m)
+		}
 		return zap.String(BodyAttr, string(item))
+	case io.Reader:
+		data, err := io.ReadAll(item)
+		if err != nil {
+			return zap.String(BodyAttr, fmt.Sprintf("%#v", val))
+		}
+		var m interface{}
+		if err := json.Unmarshal(data, &m); err == nil {
+			return zap.Any(BodyAttr, m)
+		}
+		return zap.String(BodyAttr, string(data))
 	default:
 		return zap.String(BodyAttr, fmt.Sprintf("%#v", val))
 	}

core/logger/buffer_logger_test.go

@@ -0,0 +1,263 @@
+package logger
+
+import (
+	"bufio"
+	"bytes"
+	"encoding/json"
+	"github.com/guregu/null/v5"
+	"io"
+	"os"
+	"sync"
+
+	"go.uber.org/zap"
+	"go.uber.org/zap/zapcore"
+)
+
+type logRecord struct {
+	LevelName  string                 `json:"level_name"`
+	DateTime   null.Time              `json:"datetime"`
+	Caller     string                 `json:"caller"`
+	Message    string                 `json:"message"`
+	Handler    string                 `json:"handler,omitempty"`
+	Connection string                 `json:"connection,omitempty"`
+	Account    string                 `json:"account,omitempty"`
+	Context    map[string]interface{} `json:"context,omitempty"`
+}
+
+type jSONRecordScanner struct {
+	scan *bufio.Scanner
+	buf  *bufferLogger
+}
+
+func newJSONBufferedLogger() *jSONRecordScanner {
+	buf := newBufferLogger()
+	return &jSONRecordScanner{scan: bufio.NewScanner(buf), buf: buf}
+}
+
+func (s *jSONRecordScanner) ScanAll() ([]logRecord, error) {
+	var entries []logRecord
+	for s.scan.Scan() {
+		entry := logRecord{}
+		if err := json.Unmarshal(s.scan.Bytes(), &entry); err != nil {
+			return entries, err
+		}
+		entries = append(entries, entry)
+	}
+	return entries, nil
+}
+
+func (s *jSONRecordScanner) Logger() Logger {
+	return s.buf
+}
+
+// bufferLogger is an implementation of the BufferedLogger.
+type bufferLogger struct {
+	Default
+	buf lockableBuffer
+}
+
+// NewBufferedLogger returns new BufferedLogger instance.
+func newBufferLogger() *bufferLogger {
+	bl := &bufferLogger{}
+	bl.Logger = zap.New(
+		zapcore.NewCore(
+			NewJSONWithContextEncoder(
+				EncoderConfigJSON()), zap.CombineWriteSyncers(os.Stdout, os.Stderr, &bl.buf), zapcore.DebugLevel))
+	return bl
+}
+
+func (l *bufferLogger) With(fields ...zapcore.Field) Logger {
+	return &bufferLogger{
+		Default: Default{
+			Logger: l.Logger.With(fields...),
+		},
+	}
+}
+
+func (l *bufferLogger) WithLazy(fields ...zapcore.Field) Logger {
+	return &bufferLogger{
+		Default: Default{
+			Logger: l.Logger.WithLazy(fields...),
+		},
+	}
+}
+
+func (l *bufferLogger) ForHandler(handler any) Logger {
+	return l.WithLazy(zap.Any(HandlerAttr, handler))
+}
+
+func (l *bufferLogger) ForConnection(conn any) Logger {
+	return l.WithLazy(zap.Any(ConnectionAttr, conn))
+}
+
+func (l *bufferLogger) ForAccount(acc any) Logger {
+	return l.WithLazy(zap.Any(AccountAttr, acc))
+}
+
+// Read bytes from the logger buffer. io.Reader implementation.
+func (l *bufferLogger) Read(p []byte) (n int, err error) {
+	return l.buf.Read(p)
+}
+
+// String contents of the logger buffer. fmt.Stringer implementation.
+func (l *bufferLogger) String() string {
+	return l.buf.String()
+}
+
+// Bytes is a shorthand for the underlying bytes.Buffer method. Returns byte slice with the buffer contents.
+func (l *bufferLogger) Bytes() []byte {
+	return l.buf.Bytes()
+}
+
+// Reset is a shorthand for the underlying bytes.Buffer method. It will reset buffer contents.
+func (l *bufferLogger) Reset() {
+	l.buf.Reset()
+}
+
+type lockableBuffer struct {
+	buf bytes.Buffer
+	rw  sync.RWMutex
+}
+
+func (b *lockableBuffer) Bytes() []byte {
+	defer b.rw.RUnlock()
+	b.rw.RLock()
+	return b.buf.Bytes()
+}
+
+func (b *lockableBuffer) AvailableBuffer() []byte {
+	defer b.rw.RUnlock()
+	b.rw.RLock()
+	return b.buf.AvailableBuffer()
+}
+
+func (b *lockableBuffer) String() string {
+	defer b.rw.RUnlock()
+	b.rw.RLock()
+	return b.buf.String()
+}
+
+func (b *lockableBuffer) Len() int {
+	defer b.rw.RUnlock()
+	b.rw.RLock()
+	return b.buf.Len()
+}
+
+func (b *lockableBuffer) Cap() int {
+	defer b.rw.RUnlock()
+	b.rw.RLock()
+	return b.buf.Cap()
+}
+
+func (b *lockableBuffer) Available() int {
+	defer b.rw.RUnlock()
+	b.rw.RLock()
+	return b.buf.Available()
+}
+
+func (b *lockableBuffer) Truncate(n int) {
+	defer b.rw.Unlock()
+	b.rw.Lock()
+	b.buf.Truncate(n)
+}
+
+func (b *lockableBuffer) Reset() {
+	defer b.rw.Unlock()
+	b.rw.Lock()
+	b.buf.Reset()
+}
+
+func (b *lockableBuffer) Grow(n int) {
+	defer b.rw.Unlock()
+	b.rw.Lock()
+	b.buf.Grow(n)
+}
+
+func (b *lockableBuffer) Write(p []byte) (n int, err error) {
+	defer b.rw.Unlock()
+	b.rw.Lock()
+	return b.buf.Write(p)
+}
+
+func (b *lockableBuffer) WriteString(s string) (n int, err error) {
+	defer b.rw.Unlock()
+	b.rw.Lock()
+	return b.buf.WriteString(s)
+}
+
+func (b *lockableBuffer) ReadFrom(r io.Reader) (n int64, err error) {
+	defer b.rw.Unlock()
+	b.rw.Lock()
+	return b.buf.ReadFrom(r)
+}
+
+func (b *lockableBuffer) WriteTo(w io.Writer) (n int64, err error) {
+	defer b.rw.Unlock()
+	b.rw.Lock()
+	return b.buf.WriteTo(w)
+}
+
+func (b *lockableBuffer) WriteByte(c byte) error {
+	defer b.rw.Unlock()
+	b.rw.Lock()
+	return b.buf.WriteByte(c)
+}
+
+func (b *lockableBuffer) WriteRune(r rune) (n int, err error) {
+	defer b.rw.Unlock()
+	b.rw.Lock()
+	return b.buf.WriteRune(r)
+}
+
+func (b *lockableBuffer) Read(p []byte) (n int, err error) {
+	defer b.rw.Unlock()
+	b.rw.Lock()
+	return b.buf.Read(p)
+}
+
+func (b *lockableBuffer) Next(n int) []byte {
+	defer b.rw.Unlock()
+	b.rw.Lock()
+	return b.buf.Next(n)
+}
+
+func (b *lockableBuffer) ReadByte() (byte, error) {
+	defer b.rw.Unlock()
+	b.rw.Lock()
+	return b.buf.ReadByte()
+}
+
+func (b *lockableBuffer) ReadRune() (r rune, size int, err error) {
+	defer b.rw.Unlock()
+	b.rw.Lock()
+	return b.buf.ReadRune()
+}
+
+func (b *lockableBuffer) UnreadRune() error {
+	defer b.rw.Unlock()
+	b.rw.Lock()
+	return b.buf.UnreadRune()
+}
+
+func (b *lockableBuffer) UnreadByte() error {
+	defer b.rw.Unlock()
+	b.rw.Lock()
+	return b.buf.UnreadByte()
+}
+
+func (b *lockableBuffer) ReadBytes(delim byte) (line []byte, err error) {
+	defer b.rw.Unlock()
+	b.rw.Lock()
+	return b.buf.ReadBytes(delim)
+}
+
+func (b *lockableBuffer) ReadString(delim byte) (line string, err error) {
+	defer b.rw.Unlock()
+	b.rw.Lock()
+	return b.buf.ReadString(delim)
+}
+
+// Sync is a no-op.
+func (b *lockableBuffer) Sync() error {
+	return nil
+}

core/logger/bufferpool.go

@@ -0,0 +1,29 @@
+// Copyright (c) 2016 Uber Technologies, Inc.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+package logger
+
+import "go.uber.org/zap/buffer"
+
+var (
+	_pool = buffer.NewPool()
+	// GetBufferPool retrieves a buffer from the pool, creating one if necessary.
+	GetBufferPool = _pool.Get
+)

core/logger/default.go

@@ -7,59 +7,85 @@ import (
 	"go.uber.org/zap/zapcore"
 )
 
+// Logger is a logging interface.
 type Logger interface {
+	// With adds fields to the logger and returns a new logger with those fields.
 	With(fields ...zap.Field) Logger
+	// WithLazy adds fields to the logger lazily and returns a new logger with those fields.
 	WithLazy(fields ...zap.Field) Logger
+	// Level returns the logging level of the logger.
 	Level() zapcore.Level
+	// Check checks if the log message meets the given level.
 	Check(lvl zapcore.Level, msg string) *zapcore.CheckedEntry
+	// Log logs a message with the given level and fields.
 	Log(lvl zapcore.Level, msg string, fields ...zap.Field)
+	// Debug logs a debug-level message with the given fields.
 	Debug(msg string, fields ...zap.Field)
+	// Info logs an info-level message with the given fields.
 	Info(msg string, fields ...zap.Field)
+	// Warn logs a warning-level message with the given fields.
 	Warn(msg string, fields ...zap.Field)
+	// Error logs an error-level message with the given fields.
 	Error(msg string, fields ...zap.Field)
+	// DPanic logs a debug-panic-level message with the given fields and panics if the logger's panic level is set to a non-zero value.
 	DPanic(msg string, fields ...zap.Field)
+	// Panic logs a panic-level message with the given fields and panics immediately.
 	Panic(msg string, fields ...zap.Field)
+	// Fatal logs a fatal-level message with the given fields, then calls os.Exit(1).
 	Fatal(msg string, fields ...zap.Field)
+	// ForHandler returns a new logger that is associated with the given handler.
 	ForHandler(handler any) Logger
+	// ForConnection returns a new logger that is associated with the given connection.
 	ForConnection(conn any) Logger
+	// ForAccount returns a new logger that is associated with the given account.
 	ForAccount(acc any) Logger
+	// Sync returns an error if there's a problem writing log messages to disk, or nil if all writes were successful.
 	Sync() error
 }
 
+// Default is a default logger implementation.
 type Default struct {
 	*zap.Logger
 }
 
+// NewDefault creates a new default logger with the given format and debug level.
 func NewDefault(format string, debug bool) Logger {
 	return &Default{
 		Logger: NewZap(format, debug),
 	}
 }
 
+// With adds fields to the logger and returns a new logger with those fields.
 func (l *Default) With(fields ...zap.Field) Logger {
 	return l.clone(l.Logger.With(fields...))
 }
 
+// WithLazy adds fields to the logger lazily and returns a new logger with those fields.
 func (l *Default) WithLazy(fields ...zap.Field) Logger {
 	return l.clone(l.Logger.WithLazy(fields...))
 }
 
+// ForHandler returns a new logger that is associated with the given handler.
 func (l *Default) ForHandler(handler any) Logger {
 	return l.WithLazy(zap.Any(HandlerAttr, handler))
 }
 
+// ForConnection returns a new logger that is associated with the given connection.
 func (l *Default) ForConnection(conn any) Logger {
 	return l.WithLazy(zap.Any(ConnectionAttr, conn))
 }
 
+// ForAccount returns a new logger that is associated with the given account.
 func (l *Default) ForAccount(acc any) Logger {
 	return l.WithLazy(zap.Any(AccountAttr, acc))
 }
 
+// clone creates a copy of the given logger.
 func (l *Default) clone(log *zap.Logger) Logger {
 	return &Default{Logger: log}
 }
 
+// AnyZapFields converts an array of values to zap fields.
 func AnyZapFields(args []interface{}) []zap.Field {
 	fields := make([]zap.Field, len(args))
 	for i := 0; i < len(fields); i++ {

core/logger/json_with_context_encoder.go

@@ -0,0 +1,638 @@
+// Copyright (c) 2016 Uber Technologies, Inc.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+package logger
+
+import (
+	"encoding/base64"
+	"encoding/json"
+	"fmt"
+	"go.uber.org/zap"
+	"go.uber.org/zap/zapcore"
+	"io"
+	"math"
+	"time"
+	"unicode/utf8"
+
+	"go.uber.org/zap/buffer"
+)
+
+// For JSON-escaping; see jsonWithContextEncoder.safeAddString below.
+const _hex = "0123456789abcdef"
+
+var _jsonWithContextPool = NewPool(func() *jsonWithContextEncoder {
+	return &jsonWithContextEncoder{}
+})
+
+func init() {
+	err := zap.RegisterEncoder("json-with-context", func(config zapcore.EncoderConfig) (zapcore.Encoder, error) {
+		return NewJSONWithContextEncoder(config), nil
+	})
+	if err != nil {
+		panic(err)
+	}
+}
+
+func putJSONWithContextEncoder(enc *jsonWithContextEncoder) {
+	if enc.reflectBuf != nil {
+		enc.reflectBuf.Free()
+	}
+	enc.EncoderConfig = nil
+	enc.buf = nil
+	enc.spaced = false
+	enc.openNamespaces = 0
+	enc.reflectBuf = nil
+	enc.reflectEnc = nil
+	_jsonWithContextPool.Put(enc)
+}
+
+type jsonWithContextEncoder struct {
+	*zapcore.EncoderConfig
+	buf            *buffer.Buffer
+	spaced         bool // include spaces after colons and commas
+	openNamespaces int
+
+	// for encoding generic values by reflection
+	reflectBuf *buffer.Buffer
+	reflectEnc zapcore.ReflectedEncoder
+}
+
+// NewJSONWithContextEncoder creates a fast, low-allocation JSON encoder. The encoder
+// appropriately escapes all field keys and values.
+//
+// Note that the encoder doesn't deduplicate keys, so it's possible to produce
+// a message like
+//
+//	{"foo":"bar","foo":"baz"}
+//
+// This is permitted by the JSON specification, but not encouraged. Many
+// libraries will ignore duplicate key-value pairs (typically keeping the last
+// pair) when unmarshaling, but users should attempt to avoid adding duplicate
+// keys.
+func NewJSONWithContextEncoder(cfg zapcore.EncoderConfig) zapcore.Encoder {
+	return newJSONWithContextEncoder(cfg, false)
+}
+
+func newJSONWithContextEncoder(cfg zapcore.EncoderConfig, spaced bool) *jsonWithContextEncoder {
+	if cfg.SkipLineEnding {
+		cfg.LineEnding = ""
+	} else if cfg.LineEnding == "" {
+		cfg.LineEnding = zapcore.DefaultLineEnding
+	}
+
+	// If no EncoderConfig.NewReflectedEncoder is provided by the user, then use default
+	if cfg.NewReflectedEncoder == nil {
+		cfg.NewReflectedEncoder = defaultReflectedEncoder
+	}
+
+	return &jsonWithContextEncoder{
+		EncoderConfig: &cfg,
+		buf:           GetBufferPool(),
+		spaced:        spaced,
+	}
+}
+
+func defaultReflectedEncoder(w io.Writer) zapcore.ReflectedEncoder {
+	enc := json.NewEncoder(w)
+	// For consistency with our custom JSON encoder.
+	enc.SetEscapeHTML(false)
+	return enc
+}
+
+func (enc *jsonWithContextEncoder) AddArray(key string, arr zapcore.ArrayMarshaler) error {
+	enc.addKey(key)
+	return enc.AppendArray(arr)
+}
+
+func (enc *jsonWithContextEncoder) AddObject(key string, obj zapcore.ObjectMarshaler) error {
+	enc.addKey(key)
+	return enc.AppendObject(obj)
+}
+
+func (enc *jsonWithContextEncoder) AddBinary(key string, val []byte) {
+	enc.AddString(key, base64.StdEncoding.EncodeToString(val))
+}
+
+func (enc *jsonWithContextEncoder) AddByteString(key string, val []byte) {
+	enc.addKey(key)
+	enc.AppendByteString(val)
+}
+
+func (enc *jsonWithContextEncoder) AddBool(key string, val bool) {
+	enc.addKey(key)
+	enc.AppendBool(val)
+}
+
+func (enc *jsonWithContextEncoder) AddComplex128(key string, val complex128) {
+	enc.addKey(key)
+	enc.AppendComplex128(val)
+}
+
+func (enc *jsonWithContextEncoder) AddComplex64(key string, val complex64) {
+	enc.addKey(key)
+	enc.AppendComplex64(val)
+}
+
+func (enc *jsonWithContextEncoder) AddDuration(key string, val time.Duration) {
+	enc.addKey(key)
+	enc.AppendDuration(val)
+}
+
+func (enc *jsonWithContextEncoder) AddFloat64(key string, val float64) {
+	enc.addKey(key)
+	enc.AppendFloat64(val)
+}
+
+func (enc *jsonWithContextEncoder) AddFloat32(key string, val float32) {
+	enc.addKey(key)
+	enc.AppendFloat32(val)
+}
+
+func (enc *jsonWithContextEncoder) AddInt64(key string, val int64) {
+	enc.addKey(key)
+	enc.AppendInt64(val)
+}
+
+func (enc *jsonWithContextEncoder) resetReflectBuf() {
+	if enc.reflectBuf == nil {
+		enc.reflectBuf = GetBufferPool()
+		enc.reflectEnc = enc.NewReflectedEncoder(enc.reflectBuf)
+	} else {
+		enc.reflectBuf.Reset()
+	}
+}
+
+var nullLiteralBytes = []byte("null")
+
+// Only invoke the standard JSON encoder if there is actually something to
+// encode; otherwise write JSON null literal directly.
+func (enc *jsonWithContextEncoder) encodeReflected(obj interface{}) ([]byte, error) {
+	if obj == nil {
+		return nullLiteralBytes, nil
+	}
+	enc.resetReflectBuf()
+	if err := enc.reflectEnc.Encode(obj); err != nil {
+		return nil, err
+	}
+	enc.reflectBuf.TrimNewline()
+	return enc.reflectBuf.Bytes(), nil
+}
+
+func (enc *jsonWithContextEncoder) AddReflected(key string, obj interface{}) error {
+	valueBytes, err := enc.encodeReflected(obj)
+	if err != nil {
+		return err
+	}
+	enc.addKey(key)
+	_, err = enc.buf.Write(valueBytes)
+	return err
+}
+
+func (enc *jsonWithContextEncoder) OpenNamespace(key string) {
+	enc.addKey(key)
+	enc.buf.AppendByte('{')
+	enc.openNamespaces++
+}
+
+func (enc *jsonWithContextEncoder) AddString(key, val string) {
+	enc.addKey(key)
+	enc.AppendString(val)
+}
+
+func (enc *jsonWithContextEncoder) AddTime(key string, val time.Time) {
+	enc.addKey(key)
+	enc.AppendTime(val)
+}
+
+func (enc *jsonWithContextEncoder) AddUint64(key string, val uint64) {
+	enc.addKey(key)
+	enc.AppendUint64(val)
+}
+
+func (enc *jsonWithContextEncoder) AppendArray(arr zapcore.ArrayMarshaler) error {
+	enc.addElementSeparator()
+	enc.buf.AppendByte('[')
+	err := arr.MarshalLogArray(enc)
+	enc.buf.AppendByte(']')
+	return err
+}
+
+func (enc *jsonWithContextEncoder) AppendObject(obj zapcore.ObjectMarshaler) error {
+	// Close ONLY new openNamespaces that are created during
+	// AppendObject().
+	old := enc.openNamespaces
+	enc.openNamespaces = 0
+	enc.addElementSeparator()
+	enc.buf.AppendByte('{')
+	err := obj.MarshalLogObject(enc)
+	enc.buf.AppendByte('}')
+	enc.closeOpenNamespaces()
+	enc.openNamespaces = old
+	return err
+}
+
+func (enc *jsonWithContextEncoder) AppendBool(val bool) {
+	enc.addElementSeparator()
+	enc.buf.AppendBool(val)
+}
+
+func (enc *jsonWithContextEncoder) AppendByteString(val []byte) {
+	enc.addElementSeparator()
+	enc.buf.AppendByte('"')
+	enc.safeAddByteString(val)
+	enc.buf.AppendByte('"')
+}
+
+// appendComplex appends the encoded form of the provided complex128 value.
+// precision specifies the encoding precision for the real and imaginary
+// components of the complex number.
+func (enc *jsonWithContextEncoder) appendComplex(val complex128, precision int) {
+	enc.addElementSeparator()
+	// Cast to a platform-independent, fixed-size type.
+	r, i := float64(real(val)), float64(imag(val))
+	enc.buf.AppendByte('"')
+	// Because we're always in a quoted string, we can use strconv without
+	// special-casing NaN and +/-Inf.
+	enc.buf.AppendFloat(r, precision)
+	// If imaginary part is less than 0, minus (-) sign is added by default
+	// by AppendFloat.
+	if i >= 0 {
+		enc.buf.AppendByte('+')
+	}
+	enc.buf.AppendFloat(i, precision)
+	enc.buf.AppendByte('i')
+	enc.buf.AppendByte('"')
+}
+
+func (enc *jsonWithContextEncoder) AppendDuration(val time.Duration) {
+	cur := enc.buf.Len()
+	if e := enc.EncodeDuration; e != nil {
+		e(val, enc)
+	}
+	if cur == enc.buf.Len() {
+		// User-supplied EncodeDuration is a no-op. Fall back to nanoseconds to keep
+		// JSON valid.
+		enc.AppendInt64(int64(val))
+	}
+}
+
+func (enc *jsonWithContextEncoder) AppendInt64(val int64) {
+	enc.addElementSeparator()
+	enc.buf.AppendInt(val)
+}
+
+func (enc *jsonWithContextEncoder) AppendReflected(val interface{}) error {
+	valueBytes, err := enc.encodeReflected(val)
+	if err != nil {
+		return err
+	}
+	enc.addElementSeparator()
+	_, err = enc.buf.Write(valueBytes)
+	return err
+}
+
+func (enc *jsonWithContextEncoder) AppendString(val string) {
+	enc.addElementSeparator()
+	enc.buf.AppendByte('"')
+	enc.safeAddString(val)
+	enc.buf.AppendByte('"')
+}
+
+func (enc *jsonWithContextEncoder) AppendTimeLayout(time time.Time, layout string) {
+	enc.addElementSeparator()
+	enc.buf.AppendByte('"')
+	enc.buf.AppendTime(time, layout)
+	enc.buf.AppendByte('"')
+}
+
+func (enc *jsonWithContextEncoder) AppendTime(val time.Time) {
+	cur := enc.buf.Len()
+	if e := enc.EncodeTime; e != nil {
+		e(val, enc)
+	}
+	if cur == enc.buf.Len() {
+		// User-supplied EncodeTime is a no-op. Fall back to nanos since epoch to keep
+		// output JSON valid.
+		enc.AppendInt64(val.UnixNano())
+	}
+}
+
+func (enc *jsonWithContextEncoder) AppendUint64(val uint64) {
+	enc.addElementSeparator()
+	enc.buf.AppendUint(val)
+}
+
+func (enc *jsonWithContextEncoder) AddInt(k string, v int)         { enc.AddInt64(k, int64(v)) }
+func (enc *jsonWithContextEncoder) AddInt32(k string, v int32)     { enc.AddInt64(k, int64(v)) }
+func (enc *jsonWithContextEncoder) AddInt16(k string, v int16)     { enc.AddInt64(k, int64(v)) }
+func (enc *jsonWithContextEncoder) AddInt8(k string, v int8)       { enc.AddInt64(k, int64(v)) }
+func (enc *jsonWithContextEncoder) AddUint(k string, v uint)       { enc.AddUint64(k, uint64(v)) }
+func (enc *jsonWithContextEncoder) AddUint32(k string, v uint32)   { enc.AddUint64(k, uint64(v)) }
+func (enc *jsonWithContextEncoder) AddUint16(k string, v uint16)   { enc.AddUint64(k, uint64(v)) }
+func (enc *jsonWithContextEncoder) AddUint8(k string, v uint8)     { enc.AddUint64(k, uint64(v)) }
+func (enc *jsonWithContextEncoder) AddUintptr(k string, v uintptr) { enc.AddUint64(k, uint64(v)) }
+func (enc *jsonWithContextEncoder) AppendComplex64(v complex64)    { enc.appendComplex(complex128(v), 32) }
+func (enc *jsonWithContextEncoder) AppendComplex128(v complex128) {
+	enc.appendComplex(complex128(v), 64)
+}
+func (enc *jsonWithContextEncoder) AppendFloat64(v float64) { enc.appendFloat(v, 64) }
+func (enc *jsonWithContextEncoder) AppendFloat32(v float32) { enc.appendFloat(float64(v), 32) }
+func (enc *jsonWithContextEncoder) AppendInt(v int)         { enc.AppendInt64(int64(v)) }
+func (enc *jsonWithContextEncoder) AppendInt32(v int32)     { enc.AppendInt64(int64(v)) }
+func (enc *jsonWithContextEncoder) AppendInt16(v int16)     { enc.AppendInt64(int64(v)) }
+func (enc *jsonWithContextEncoder) AppendInt8(v int8)       { enc.AppendInt64(int64(v)) }
+func (enc *jsonWithContextEncoder) AppendUint(v uint)       { enc.AppendUint64(uint64(v)) }
+func (enc *jsonWithContextEncoder) AppendUint32(v uint32)   { enc.AppendUint64(uint64(v)) }
+func (enc *jsonWithContextEncoder) AppendUint16(v uint16)   { enc.AppendUint64(uint64(v)) }
+func (enc *jsonWithContextEncoder) AppendUint8(v uint8)     { enc.AppendUint64(uint64(v)) }
+func (enc *jsonWithContextEncoder) AppendUintptr(v uintptr) { enc.AppendUint64(uint64(v)) }
+
+func (enc *jsonWithContextEncoder) Clone() zapcore.Encoder {
+	clone := enc.clone()
+	clone.buf.Write(enc.buf.Bytes())
+	return clone
+}
+
+func (enc *jsonWithContextEncoder) clone() *jsonWithContextEncoder {
+	clone := _jsonWithContextPool.Get()
+	clone.EncoderConfig = enc.EncoderConfig
+	clone.spaced = enc.spaced
+	clone.openNamespaces = enc.openNamespaces
+	clone.buf = GetBufferPool()
+	return clone
+}
+
+func (enc *jsonWithContextEncoder) EncodeEntry(ent zapcore.Entry, fields []zapcore.Field) (*buffer.Buffer, error) {
+	final := enc.clone()
+	final.buf.AppendByte('{')
+
+	if final.LevelKey != "" && final.EncodeLevel != nil {
+		final.addKey(final.LevelKey)
+		cur := final.buf.Len()
+		final.EncodeLevel(ent.Level, final)
+		if cur == final.buf.Len() {
+			// User-supplied EncodeLevel was a no-op. Fall back to strings to keep
+			// output JSON valid.
+			final.AppendString(ent.Level.String())
+		}
+	}
+	if final.TimeKey != "" {
+		final.AddTime(final.TimeKey, ent.Time)
+	}
+	if ent.LoggerName != "" && final.NameKey != "" {
+		final.addKey(final.NameKey)
+		cur := final.buf.Len()
+		nameEncoder := final.EncodeName
+
+		// if no name encoder provided, fall back to FullNameEncoder for backwards
+		// compatibility
+		if nameEncoder == nil {
+			nameEncoder = zapcore.FullNameEncoder
+		}
+
+		nameEncoder(ent.LoggerName, final)
+		if cur == final.buf.Len() {
+			// User-supplied EncodeName was a no-op. Fall back to strings to
+			// keep output JSON valid.
+			final.AppendString(ent.LoggerName)
+		}
+	}
+	if ent.Caller.Defined {
+		if final.CallerKey != "" {
+			final.addKey(final.CallerKey)
+			cur := final.buf.Len()
+			final.EncodeCaller(ent.Caller, final)
+			if cur == final.buf.Len() {
+				// User-supplied EncodeCaller was a no-op. Fall back to strings to
+				// keep output JSON valid.
+				final.AppendString(ent.Caller.String())
+			}
+		}
+		if final.FunctionKey != "" {
+			final.addKey(final.FunctionKey)
+			final.AppendString(ent.Caller.Function)
+		}
+	}
+	if final.MessageKey != "" {
+		final.addKey(enc.MessageKey)
+		final.AppendString(ent.Message)
+	}
+	if enc.buf.Len() > 0 {
+		final.addElementSeparator()
+		final.buf.Write(enc.buf.Bytes())
+	}
+	addFields(final, fields)
+	final.closeOpenNamespaces()
+	if ent.Stack != "" && final.StacktraceKey != "" {
+		final.AddString(final.StacktraceKey, ent.Stack)
+	}
+	final.buf.AppendByte('}')
+	final.buf.AppendString(final.LineEnding)
+
+	ret := final.buf
+	putJSONWithContextEncoder(final)
+	return ret, nil
+}
+
+func addFields(enc zapcore.ObjectEncoder, fields []zapcore.Field) {
+	m := make(map[string]interface{})
+	hasEntries := false
+	for _, f := range fields {
+		switch f.Key {
+		case HandlerAttr, ConnectionAttr, AccountAttr:
+			f.AddTo(enc)
+		default:
+			hasEntries = true
+			if f.Interface != nil {
+				switch t := f.Interface.(type) {
+				case fmt.Stringer:
+					m[f.Key] = t.String()
+				case fmt.GoStringer:
+					m[f.Key] = t.GoString()
+				case error:
+					m[f.Key] = t.Error()
+				default:
+					m[f.Key] = f.Interface
+				}
+				continue
+			}
+			if f.String != "" {
+				m[f.Key] = f.String
+				continue
+			}
+			m[f.Key] = f.Integer
+		}
+	}
+	if hasEntries {
+		zap.Any("context", m).AddTo(enc)
+	}
+}
+
+func (enc *jsonWithContextEncoder) truncate() {
+	enc.buf.Reset()
+}
+
+func (enc *jsonWithContextEncoder) closeOpenNamespaces() {
+	for i := 0; i < enc.openNamespaces; i++ {
+		enc.buf.AppendByte('}')
+	}
+	enc.openNamespaces = 0
+}
+
+func (enc *jsonWithContextEncoder) addKey(key string) {
+	enc.addElementSeparator()
+	enc.buf.AppendByte('"')
+	enc.safeAddString(key)
+	enc.buf.AppendByte('"')
+	enc.buf.AppendByte(':')
+	if enc.spaced {
+		enc.buf.AppendByte(' ')
+	}
+}
+
+func (enc *jsonWithContextEncoder) addElementSeparator() {
+	last := enc.buf.Len() - 1
+	if last < 0 {
+		return
+	}
+	switch enc.buf.Bytes()[last] {
+	case '{', '[', ':', ',', ' ':
+		return
+	default:
+		enc.buf.AppendByte(',')
+		if enc.spaced {
+			enc.buf.AppendByte(' ')
+		}
+	}
+}
+
+func (enc *jsonWithContextEncoder) appendFloat(val float64, bitSize int) {
+	enc.addElementSeparator()
+	switch {
+	case math.IsNaN(val):
+		enc.buf.AppendString(`"NaN"`)
+	case math.IsInf(val, 1):
+		enc.buf.AppendString(`"+Inf"`)
+	case math.IsInf(val, -1):
+		enc.buf.AppendString(`"-Inf"`)
+	default:
+		enc.buf.AppendFloat(val, bitSize)
+	}
+}
+
+// safeAddString JSON-escapes a string and appends it to the internal buffer.
+// Unlike the standard library's encoder, it doesn't attempt to protect the
+// user from browser vulnerabilities or JSONP-related problems.
+func (enc *jsonWithContextEncoder) safeAddString(s string) {
+	safeAppendStringLike(
+		(*buffer.Buffer).AppendString,
+		utf8.DecodeRuneInString,
+		enc.buf,
+		s,
+	)
+}
+
+// safeAddByteString is no-alloc equivalent of safeAddString(string(s)) for s []byte.
+func (enc *jsonWithContextEncoder) safeAddByteString(s []byte) {
+	safeAppendStringLike(
+		(*buffer.Buffer).AppendBytes,
+		utf8.DecodeRune,
+		enc.buf,
+		s,
+	)
+}
+
+// safeAppendStringLike is a generic implementation of safeAddString and safeAddByteString.
+// It appends a string or byte slice to the buffer, escaping all special characters.
+func safeAppendStringLike[S []byte | string](
+	// appendTo appends this string-like object to the buffer.
+	appendTo func(*buffer.Buffer, S),
+	// decodeRune decodes the next rune from the string-like object
+	// and returns its value and width in bytes.
+	decodeRune func(S) (rune, int),
+	buf *buffer.Buffer,
+	s S,
+) {
+	// The encoding logic below works by skipping over characters
+	// that can be safely copied as-is,
+	// until a character is found that needs special handling.
+	// At that point, we copy everything we've seen so far,
+	// and then handle that special character.
+	//
+	// last is the index of the last byte that was copied to the buffer.
+	last := 0
+	for i := 0; i < len(s); {
+		if s[i] >= utf8.RuneSelf {
+			// Character >= RuneSelf may be part of a multi-byte rune.
+			// They need to be decoded before we can decide how to handle them.
+			r, size := decodeRune(s[i:])
+			if r != utf8.RuneError || size != 1 {
+				// No special handling required.
+				// Skip over this rune and continue.
+				i += size
+				continue
+			}
+
+			// Invalid UTF-8 sequence.
+			// Replace it with the Unicode replacement character.
+			appendTo(buf, s[last:i])
+			buf.AppendString(`\ufffd`)
+
+			i++
+			last = i
+		} else {
+			// Character < RuneSelf is a single-byte UTF-8 rune.
+			if s[i] >= 0x20 && s[i] != '\\' && s[i] != '"' {
+				// No escaping necessary.
+				// Skip over this character and continue.
+				i++
+				continue
+			}
+
+			// This character needs to be escaped.
+			appendTo(buf, s[last:i])
+			switch s[i] {
+			case '\\', '"':
+				buf.AppendByte('\\')
+				buf.AppendByte(s[i])
+			case '\n':
+				buf.AppendByte('\\')
+				buf.AppendByte('n')
+			case '\r':
+				buf.AppendByte('\\')
+				buf.AppendByte('r')
+			case '\t':
+				buf.AppendByte('\\')
+				buf.AppendByte('t')
+			default:
+				// Encode bytes < 0x20, except for the escape sequences above.
+				buf.AppendString(`\u00`)
+				buf.AppendByte(_hex[s[i]>>4])
+				buf.AppendByte(_hex[s[i]&0xF])
+			}
+
+			i++
+			last = i
+		}
+	}
+
+	// add remaining
+	appendTo(buf, s[last:])
+}

core/logger/mg_transport_client_adapter.go

@@ -2,18 +2,57 @@ package logger
 
 import (
 	"fmt"
-
 	v1 "github.com/retailcrm/mg-transport-api-client-go/v1"
+	"go.uber.org/zap"
+)
+
+const (
+	mgDebugLogReq     = "MG TRANSPORT API Request: %s %s %s %v"
+	mgDebugLogReqFile = "MG TRANSPORT API Request: %s %s %s [file data]"
+	mgDebugLogResp    = "MG TRANSPORT API Response: %s"
 )
 
 type mgTransportClientAdapter struct {
 	log Logger
 }
 
-func MGTransportClientAdapter(log Logger) v1.DebugLogger {
+// MGTransportClientAdapter constructs an adapter that will log MG requests and responses.
+func MGTransportClientAdapter(log Logger) v1.BasicLogger {
 	return &mgTransportClientAdapter{log: log}
 }
 
+// Debugf writes a message with Debug level.
 func (m *mgTransportClientAdapter) Debugf(msg string, args ...interface{}) {
-	m.log.Debug(fmt.Sprintf(msg, args...))
+	var body interface{}
+	switch msg {
+	case mgDebugLogReqFile:
+		body = "[file data]"
+		fallthrough
+	case mgDebugLogReq:
+		var method, uri, token string
+		if len(args) > 0 {
+			method = fmt.Sprint(args[0])
+		}
+		if len(args) > 1 {
+			uri = fmt.Sprint(args[1])
+		}
+		if len(args) > 2 {
+			token = fmt.Sprint(args[2])
+		}
+		if len(args) > 3 {
+			body = args[3]
+		}
+		m.log.Debug("MG TRANSPORT API Request",
+			zap.String(HTTPMethodAttr, method), zap.String("url", uri),
+			zap.String("token", token), Body(body))
+	case mgDebugLogResp:
+		m.log.Debug("MG TRANSPORT API Response", Body(args[0]))
+	default:
+		m.log.Debug(fmt.Sprintf(msg, args...))
+	}
+}
+
+// Printf is a v1.BasicLogger implementation.
+func (m *mgTransportClientAdapter) Printf(msg string, args ...interface{}) {
+	m.Debugf(msg, args...)
 }

core/logger/mg_transport_client_adapter_test.go

@@ -0,0 +1,43 @@
+package logger
+
+import (
+	"github.com/h2non/gock"
+	v1 "github.com/retailcrm/mg-transport-api-client-go/v1"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"net/http"
+	"testing"
+)
+
+func TestMGTransportClientAdapter(t *testing.T) {
+	httpClient := &http.Client{}
+	log := newJSONBufferedLogger()
+	client := v1.NewWithClient("https://mg.dev", "test_token", httpClient).
+		WithLogger(MGTransportClientAdapter(log.Logger()))
+	client.Debug = true
+
+	defer gock.Off()
+	gock.New("https://mg.dev").
+		Get("/api/transport/v1/channels").
+		Reply(http.StatusOK).
+		JSON([]v1.ChannelListItem{{ID: 123}})
+
+	_, _, err := client.TransportChannels(v1.Channels{})
+	require.NoError(t, err)
+
+	entries, err := log.ScanAll()
+	require.NoError(t, err)
+	require.Len(t, entries, 2)
+
+	assert.Equal(t, "DEBUG", entries[0].LevelName)
+	assert.True(t, entries[0].DateTime.Valid)
+	assert.Equal(t, "MG TRANSPORT API Request", entries[0].Message)
+	assert.Equal(t, http.MethodGet, entries[0].Context["method"])
+	assert.Equal(t, "test_token", entries[0].Context["token"])
+	assert.Equal(t, "https://mg.dev/api/transport/v1/channels?", entries[0].Context["url"])
+
+	assert.Equal(t, "DEBUG", entries[1].LevelName)
+	assert.True(t, entries[1].DateTime.Valid)
+	assert.Equal(t, "MG TRANSPORT API Response", entries[1].Message)
+	assert.Equal(t, float64(123), entries[1].Context["body"].([]interface{})[0].(map[string]interface{})["id"])
+}

core/logger/nil.go

@@ -5,8 +5,10 @@ import (
 	"go.uber.org/zap/zapcore"
 )
 
+// Nil logger doesn't do anything.
 type Nil struct{}
 
+// NewNil constructs new *Nil.
 func NewNil() Logger {
 	return &Nil{}
 }

core/logger/pool.go

@@ -0,0 +1,57 @@
+// Copyright (c) 2023 Uber Technologies, Inc.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+package logger
+
+import (
+	"sync"
+)
+
+// A Pool is a generic wrapper around [sync.Pool] to provide strongly-typed
+// object pooling.
+//
+// Note that SA6002 (ref: https://staticcheck.io/docs/checks/#SA6002) will
+// not be detected, so all internal pool use must take care to only store
+// pointer types.
+type Pool[T any] struct {
+	pool sync.Pool
+}
+
+// NewPool returns a new [Pool] for T, and will use fn to construct new Ts when
+// the pool is empty.
+func NewPool[T any](fn func() T) *Pool[T] {
+	return &Pool[T]{
+		pool: sync.Pool{
+			New: func() any {
+				return fn()
+			},
+		},
+	}
+}
+
+// Get gets a T from the pool, or creates a new one if the pool is empty.
+func (p *Pool[T]) Get() T {
+	return p.pool.Get().(T)
+}
+
+// Put returns x into the pool.
+func (p *Pool[T]) Put(x T) {
+	p.pool.Put(x)
+}

core/logger/writer_adapter.go

@@ -11,6 +11,7 @@ type writerAdapter struct {
 	level zapcore.Level
 }
 
+// WriterAdapter returns an io.Writer that can be used to write log messages. Message level is preconfigured.
 func WriterAdapter(log Logger, level zapcore.Level) io.Writer {
 	return &writerAdapter{log: log, level: level}
 }

core/logger/zabbix_collector_adapter.go

@@ -11,9 +11,24 @@ type zabbixCollectorAdapter struct {
 }
 
 func (a *zabbixCollectorAdapter) Errorf(format string, args ...interface{}) {
-	a.log.Error(fmt.Sprintf(format, args...))
+	baseMsg := "cannot send metrics to Zabbix"
+	switch format {
+	case "cannot send metrics to Zabbix: %v":
+		baseMsg = "cannot stop collector"
+		fallthrough
+	case "cannot stop collector: %s":
+		var err interface{}
+		if len(args) > 0 {
+			err = args[0]
+		}
+		a.log.Error(baseMsg, Err(err))
+	default:
+		a.log.Error(fmt.Sprintf(format, args...))
+	}
 }
 
+// ZabbixCollectorAdapter works as a logger adapter for Zabbix metrics collector.
+// It can extract error messages from Zabbix collector and convert them to structured format.
 func ZabbixCollectorAdapter(log Logger) metrics.ErrorLogger {
 	return &zabbixCollectorAdapter{log: log}
 }

core/logger/zap.go

@@ -71,7 +71,7 @@ func NewZapJSON(debug bool) *zap.Logger {
 	log, err := zap.Config{
 		Level:            zap.NewAtomicLevelAt(level),
 		Development:      debug,
-		Encoding:         "json",
+		Encoding:         "json-with-context",
 		EncoderConfig:    EncoderConfigJSON(),
 		OutputPaths:      []string{"stdout"},
 		ErrorOutputPaths: []string{"stderr"},

core/util/httputil/http_client_builder_test.go

@@ -142,7 +142,7 @@ func (t *HTTPClientBuilderTest) Test_WithLogger() {
 	builder.WithLogger(nil)
 	assert.Nil(t.T(), builder.logger)
 
-	log := logger.NewDefault("console", true)
+	log := logger.NewDefault("json", true)
 	builder.WithLogger(log)
 	assert.NotNil(t.T(), builder.logger)
 }

core/util/testutil/buffer_logger.go

@@ -36,8 +36,8 @@ func NewBufferedLogger() BufferedLogger {
 	bl := &BufferLogger{}
 	bl.Logger = zap.New(
 		zapcore.NewCore(
-			zapcore.NewConsoleEncoder(
+			logger.NewJSONWithContextEncoder(
-				logger.EncoderConfigConsole()), zap.CombineWriteSyncers(os.Stdout, os.Stderr, &bl.buf), zapcore.DebugLevel))
+				logger.EncoderConfigJSON()), zap.CombineWriteSyncers(os.Stdout, os.Stderr, &bl.buf), zapcore.DebugLevel))
 	return bl
 }
 

core/util/testutil/buffer_logger_test.go

@@ -29,17 +29,20 @@ func (t *BufferLoggerTest) Test_Read() {
 
 	data, err := io.ReadAll(t.logger)
 	t.Require().NoError(err)
-	t.Assert().Contains(string(data), "level=DEBUG test")
+	t.Assert().Contains(string(data), "\"level_name\":\"DEBUG\"")
+	t.Assert().Contains(string(data), "\"message\":\"test\"")
 }
 
 func (t *BufferLoggerTest) Test_Bytes() {
 	t.logger.Debug("test")
-	t.Assert().Contains(string(t.logger.Bytes()), "level=DEBUG test")
+	t.Assert().Contains(string(t.logger.Bytes()), "\"level_name\":\"DEBUG\"")
+	t.Assert().Contains(string(t.logger.Bytes()), "\"message\":\"test\"")
 }
 
 func (t *BufferLoggerTest) Test_String() {
 	t.logger.Debug("test")
-	t.Assert().Contains(t.logger.String(), "level=DEBUG test")
+	t.Assert().Contains(t.logger.String(), "\"level_name\":\"DEBUG\"")
+	t.Assert().Contains(t.logger.String(), "\"message\":\"test\"")
 }
 
 func (t *BufferLoggerTest) TestRace() {

core/util/testutil/json_record_scanner.go

@@ -0,0 +1,51 @@
+package testutil
+
+import (
+	"bufio"
+	"encoding/json"
+	"github.com/guregu/null/v5"
+	"io"
+)
+
+type LogRecord struct {
+	LevelName  string                 `json:"level_name"`
+	DateTime   null.Time              `json:"datetime"`
+	Caller     string                 `json:"caller"`
+	Message    string                 `json:"message"`
+	Handler    string                 `json:"handler,omitempty"`
+	Connection string                 `json:"connection,omitempty"`
+	Account    string                 `json:"account,omitempty"`
+	Context    map[string]interface{} `json:"context,omitempty"`
+}
+
+type JSONRecordScanner struct {
+	r *bufio.Scanner
+	e LogRecord
+}
+
+func NewJSONRecordScanner(entryProvider io.Reader) *JSONRecordScanner {
+	return &JSONRecordScanner{r: bufio.NewScanner(entryProvider)}
+}
+
+func (s *JSONRecordScanner) Scan() error {
+	if s.r.Scan() {
+		return json.Unmarshal(s.r.Bytes(), &s.e)
+	}
+	return io.EOF
+}
+
+func (s *JSONRecordScanner) ScanAll() ([]LogRecord, error) {
+	var entries []LogRecord
+	for s.r.Scan() {
+		entry := LogRecord{}
+		if err := json.Unmarshal(s.r.Bytes(), &entry); err != nil {
+			return entries, err
+		}
+		entries = append(entries, entry)
+	}
+	return entries, nil
+}
+
+func (s *JSONRecordScanner) Entry() LogRecord {
+	return s.e
+}

core/util/testutil/json_record_scanner_test.go

@@ -0,0 +1,107 @@
+package testutil
+
+import (
+	"bytes"
+	"github.com/stretchr/testify/suite"
+	"io"
+	"strings"
+	"testing"
+	"time"
+)
+
+type JSONRecordScannerTest struct {
+	suite.Suite
+}
+
+func TestJSONRecordScanner(t *testing.T) {
+	suite.Run(t, new(JSONRecordScannerTest))
+}
+
+func (t *JSONRecordScannerTest) new(lines []string) *JSONRecordScanner {
+	return NewJSONRecordScanner(bytes.NewReader([]byte(strings.Join(lines, "\n"))))
+}
+
+func (t *JSONRecordScannerTest) newPredefined() *JSONRecordScanner {
+	return t.new([]string{strings.ReplaceAll(`{
+  "level_name": "ERROR",
+  "datetime": "2024-06-07T13:49:17+03:00",
+  "caller": "handlers/account_middleware.go:147",
+  "message": "Cannot add account",
+  "handler": "handlers.addAccount",
+  "connection": "https://fake-uri.retailcrm.pro",
+  "account": "@username",
+  "context": {
+    "body": "[]string{\"integration_read\", \"integration_write\"}",
+    "statusCode": 500
+  }
+}`, "\n", "")})
+}
+
+func (t *JSONRecordScannerTest) assertPredefined(record LogRecord) {
+	ts, err := time.Parse(time.RFC3339, "2024-06-07T13:49:17+03:00")
+	t.Require().NoError(err)
+	t.Assert().True(record.DateTime.Valid)
+	t.Assert().Equal(ts, record.DateTime.Time)
+	t.Assert().Equal("ERROR", record.LevelName)
+	t.Assert().Equal("handlers/account_middleware.go:147", record.Caller)
+	t.Assert().Equal("Cannot add account", record.Message)
+	t.Assert().Equal("handlers.addAccount", record.Handler)
+	t.Assert().Equal("https://fake-uri.retailcrm.pro", record.Connection)
+	t.Assert().Equal("@username", record.Account)
+	t.Assert().Equal("[]string{\"integration_read\", \"integration_write\"}", record.Context["body"])
+	t.Assert().Equal(float64(500), record.Context["statusCode"])
+}
+
+func (t *JSONRecordScannerTest) TestScan_NotJSON() {
+	rs := t.new([]string{"this is", "not json"})
+	t.Assert().Error(rs.Scan())
+}
+
+func (t *JSONRecordScannerTest) TestScan_PartialJSON() {
+	rs := t.new([]string{"{}", "not json"})
+	t.Assert().NoError(rs.Scan())
+	t.Assert().Error(rs.Scan())
+}
+
+func (t *JSONRecordScannerTest) TestScan_JSON() {
+	rs := t.new([]string{"{}", "{}"})
+	t.Assert().NoError(rs.Scan())
+	t.Assert().NoError(rs.Scan())
+	t.Assert().ErrorIs(rs.Scan(), io.EOF)
+}
+
+func (t *JSONRecordScannerTest) TestScan_JSONRecord() {
+	rs := t.newPredefined()
+	t.Assert().NoError(rs.Scan())
+	t.Assert().ErrorIs(rs.Scan(), io.EOF)
+	t.assertPredefined(rs.Entry())
+}
+
+func (t *JSONRecordScannerTest) TestScanAll_NotJSON() {
+	rs := t.new([]string{"this is", "not json"})
+	records, err := rs.ScanAll()
+	t.Assert().Error(err)
+	t.Assert().Empty(records)
+}
+
+func (t *JSONRecordScannerTest) TestScanAll_PartialJSON() {
+	rs := t.new([]string{"{}", "not json"})
+	records, err := rs.ScanAll()
+	t.Assert().Error(err)
+	t.Assert().Len(records, 1)
+}
+
+func (t *JSONRecordScannerTest) TestScanAll_JSON() {
+	rs := t.new([]string{"{}", "{}"})
+	records, err := rs.ScanAll()
+	t.Assert().NoError(err)
+	t.Assert().Len(records, 2)
+}
+
+func (t *JSONRecordScannerTest) TestScanAll_JSONRecord() {
+	rs := t.newPredefined()
+	records, err := rs.ScanAll()
+	t.Assert().NoError(err)
+	t.Assert().Len(records, 1)
+	t.assertPredefined(records[0])
+}

core/util/utils_test.go

@@ -38,7 +38,7 @@ func mgClient() *v1.MgClient {
 }
 
 func (u *UtilsTest) SetupSuite() {
-	logger := logger.NewDefault("console", true)
+	logger := logger.NewDefault("json", true)
 	awsConfig := config.AWS{
 		AccessKeyID:     "access key id (will be removed)",
 		SecretAccessKey: "secret access key",

go.mod

@@ -1,6 +1,8 @@
 module github.com/retailcrm/mg-transport-core/v2
 
-go 1.21
+go 1.21.4
+
+toolchain go1.22.0
 
 require (
 	github.com/DATA-DOG/go-sqlmock v1.3.3
@@ -17,6 +19,7 @@ require (
 	github.com/gomarkdown/markdown v0.0.0-20221013030248-663e2500819c
 	github.com/gorilla/securecookie v1.1.1
 	github.com/gorilla/sessions v1.2.0
+	github.com/guregu/null/v5 v5.0.0
 	github.com/h2non/gock v1.2.0
 	github.com/jessevdk/go-flags v1.4.0
 	github.com/jinzhu/gorm v1.9.11

go.sum

@@ -238,6 +238,8 @@ github.com/gorilla/securecookie v1.1.1/go.mod h1:ra0sb63/xPlUeL+yeDciTfxMRAA+MP+
 github.com/gorilla/sessions v1.2.0 h1:S7P+1Hm5V/AT9cjEcUD5uDaQSX0OE577aCXgoaKpYbQ=
 github.com/gorilla/sessions v1.2.0/go.mod h1:dk2InVEVJ0sfLlnXv9EAgkf6ecYs/i80K/zI+bUmuGM=
 github.com/gorilla/websocket v1.4.1/go.mod h1:YR8l580nyteQvAITg2hZ9XVh4b55+EU/adAjf1fMHhE=
+github.com/guregu/null/v5 v5.0.0 h1:PRxjqyOekS11W+w/7Vfz6jgJE/BCwELWtgvOJzddimw=
+github.com/guregu/null/v5 v5.0.0/go.mod h1:SjupzNy+sCPtwQTKWhUCqjhVCO69hpsl2QsZrWHjlwU=
 github.com/h2non/gock v1.2.0 h1:K6ol8rfrRkUOefooBC8elXoaNGYkpp7y2qcxGG6BzUE=
 github.com/h2non/gock v1.2.0/go.mod h1:tNhoxHYW2W42cYkYb1WqzdbYIieALC99kpYr7rH/BQk=
 github.com/h2non/parth v0.0.0-20190131123155-b4df798d6542 h1:2VTzZjLZBgl62/EtslCrtky5vbi9dd7HrQPQIx6wqiw=