Merge pull request #143 from wneessen/feature/142_implement-structure…

…d-json-logger

#142 Add structured JSON logger and associated tests

log/jsonlog.go

@@ -0,0 +1,82 @@
+// SPDX-FileCopyrightText: Copyright (c) 2023 The go-mail Authors
+//
+// SPDX-License-Identifier: MIT
+
+//go:build go1.21
+// +build go1.21
+
+package log
+
+import (
+ "fmt"
+ "io"
+ "log/slog"
+)
+
+// JSONlog is the default structured JSON logger that satisfies the Logger interface
+type JSONlog struct {
+ l Level
+ log *slog.Logger
+}
+
+// NewJSON returns a new JSONlog type that satisfies the Logger interface
+func NewJSON(o io.Writer, l Level) *JSONlog {
+ lo := slog.HandlerOptions{}
+ switch l {
+ case LevelDebug:
+ lo.Level = slog.LevelDebug
+ case LevelInfo:
+ lo.Level = slog.LevelInfo
+ case LevelWarn:
+ lo.Level = slog.LevelWarn
+ case LevelError:
+ lo.Level = slog.LevelError
+ default:
+ lo.Level = slog.LevelDebug
+ }
+ lh := slog.NewJSONHandler(o, &lo)
+ return &JSONlog{
+ l: l,
+ log: slog.New(lh),
+ }
+}
+
+// Debugf logs a debug message via the structured JSON logger
+func (l *JSONlog) Debugf(lo Log) {
+ if l.l >= LevelDebug {
+ l.log.WithGroup(DirString).With(
+ slog.String(DirFromString, lo.directionFrom()),
+ slog.String(DirToString, lo.directionTo()),
+ ).Debug(fmt.Sprintf(lo.Format, lo.Messages...))
+ }
+}
+
+// Infof logs a info message via the structured JSON logger
+func (l *JSONlog) Infof(lo Log) {
+ if l.l >= LevelInfo {
+ l.log.WithGroup(DirString).With(
+ slog.String(DirFromString, lo.directionFrom()),
+ slog.String(DirToString, lo.directionTo()),
+ ).Info(fmt.Sprintf(lo.Format, lo.Messages...))
+ }
+}
+
+// Warnf logs a warn message via the structured JSON logger
+func (l *JSONlog) Warnf(lo Log) {
+ if l.l >= LevelWarn {
+ l.log.WithGroup(DirString).With(
+ slog.String(DirFromString, lo.directionFrom()),
+ slog.String(DirToString, lo.directionTo()),
+ ).Warn(fmt.Sprintf(lo.Format, lo.Messages...))
+ }
+}
+
+// Errorf logs a warn message via the structured JSON logger
+func (l *JSONlog) Errorf(lo Log) {
+ if l.l >= LevelError {
+ l.log.WithGroup(DirString).With(
+ slog.String(DirFromString, lo.directionFrom()),
+ slog.String(DirToString, lo.directionTo()),
+ ).Error(fmt.Sprintf(lo.Format, lo.Messages...))
+ }
+}

log/jsonlog_test.go

@@ -0,0 +1,297 @@
+// SPDX-FileCopyrightText: Copyright (c) 2023 The go-mail Authors
+//
+// SPDX-License-Identifier: MIT
+
+//go:build go1.21
+// +build go1.21
+
+package log
+
+import (
+ "bytes"
+ "encoding/json"
+ "fmt"
+ "testing"
+ "time"
+)
+
+type jsonLog struct {
+ Direction jsonDir `json:"direction"`
+ Level string `json:"level"`
+ Message string `json:"msg"`
+ Time time.Time `json:"time"`
+}
+
+type jsonDir struct {
+ From string `json:"from"`
+ To string `json:"to"`
+}
+
+func TestNewJSON(t *testing.T) {
+ var b bytes.Buffer
+ l := NewJSON(&b, LevelDebug)
+ if l.l != LevelDebug {
+ t.Error("Expected level to be LevelDebug, got ", l.l)
+ }
+ if l.log == nil {
+ t.Error("logger not initialized")
+ }
+}
+
+func TestJSONDebugf(t *testing.T) {
+ var b bytes.Buffer
+ l := NewJSON(&b, LevelDebug)
+ f := "test %s"
+ msg := "foo"
+ msg2 := "bar"
+
+ l.Debugf(Log{Direction: DirServerToClient, Format: f, Messages: []interface{}{msg}})
+ exFrom := "server"
+ exTo := "client"
+ jl, err := unmarshalLog(b.Bytes())
+ if err != nil {
+ t.Errorf("Debugf() failed, unmarshal json log message failed: %s", err)
+ }
+ if jl.Direction.To != exTo {
+ t.Errorf("Debugf() failed, expected message to: %s, got: %s", exTo, jl.Direction.To)
+ }
+ if jl.Direction.From != exFrom {
+ t.Errorf("Debugf() failed, expected message to: %s, got: %s", exFrom, jl.Direction.From)
+ }
+ if jl.Message != fmt.Sprintf(f, msg) {
+ t.Errorf("Debugf() failed, expected message: %s, got %s", msg, jl.Message)
+ }
+
+ b.Reset()
+ l.Debugf(Log{Direction: DirClientToServer, Format: f, Messages: []interface{}{msg2}})
+ exFrom = "client"
+ exTo = "server"
+ jl, err = unmarshalLog(b.Bytes())
+ if err != nil {
+ t.Errorf("Debugf() failed, unmarshal json log message failed: %s", err)
+ }
+ if jl.Direction.To != exTo {
+ t.Errorf("Debugf() failed, expected message to: %s, got: %s", exTo, jl.Direction.To)
+ }
+ if jl.Direction.From != exFrom {
+ t.Errorf("Debugf() failed, expected message to: %s, got: %s", exFrom, jl.Direction.From)
+ }
+ if jl.Message != fmt.Sprintf(f, msg2) {
+ t.Errorf("Debugf() failed, expected message: %s, got %s", msg2, jl.Message)
+ }
+
+ b.Reset()
+ l.l = LevelInfo
+ l.Debugf(Log{Direction: DirServerToClient, Format: "test %s", Messages: []interface{}{"foo"}})
+ if b.String() != "" {
+ t.Error("Debug message was not expected to be logged")
+ }
+}
+
+func TestJSONDebugf_WithDefault(t *testing.T) {
+ var b bytes.Buffer
+ l := NewJSON(&b, 999)
+ f := "test %s"
+ msg := "foo"
+ msg2 := "bar"
+
+ l.Debugf(Log{Direction: DirServerToClient, Format: f, Messages: []interface{}{msg}})
+ exFrom := "server"
+ exTo := "client"
+ jl, err := unmarshalLog(b.Bytes())
+ if err != nil {
+ t.Errorf("Debugf() failed, unmarshal json log message failed: %s", err)
+ }
+ if jl.Direction.To != exTo {
+ t.Errorf("Debugf() failed, expected message to: %s, got: %s", exTo, jl.Direction.To)
+ }
+ if jl.Direction.From != exFrom {
+ t.Errorf("Debugf() failed, expected message to: %s, got: %s", exFrom, jl.Direction.From)
+ }
+ if jl.Message != fmt.Sprintf(f, msg) {
+ t.Errorf("Debugf() failed, expected message: %s, got %s", msg, jl.Message)
+ }
+
+ b.Reset()
+ l.Debugf(Log{Direction: DirClientToServer, Format: f, Messages: []interface{}{msg2}})
+ exFrom = "client"
+ exTo = "server"
+ jl, err = unmarshalLog(b.Bytes())
+ if err != nil {
+ t.Errorf("Debugf() failed, unmarshal json log message failed: %s", err)
+ }
+ if jl.Direction.To != exTo {
+ t.Errorf("Debugf() failed, expected message to: %s, got: %s", exTo, jl.Direction.To)
+ }
+ if jl.Direction.From != exFrom {
+ t.Errorf("Debugf() failed, expected message to: %s, got: %s", exFrom, jl.Direction.From)
+ }
+ if jl.Message != fmt.Sprintf(f, msg2) {
+ t.Errorf("Debugf() failed, expected message: %s, got %s", msg2, jl.Message)
+ }
+
+ b.Reset()
+ l.l = LevelInfo
+ l.Debugf(Log{Direction: DirServerToClient, Format: "test %s", Messages: []interface{}{"foo"}})
+ if b.String() != "" {
+ t.Error("Debug message was not expected to be logged")
+ }
+}
+
+func TestJSONInfof(t *testing.T) {
+ var b bytes.Buffer
+ l := NewJSON(&b, LevelInfo)
+ f := "test %s"
+ msg := "foo"
+ msg2 := "bar"
+
+ l.Infof(Log{Direction: DirServerToClient, Format: f, Messages: []interface{}{msg}})
+ exFrom := "server"
+ exTo := "client"
+ jl, err := unmarshalLog(b.Bytes())
+ if err != nil {
+ t.Errorf("Debugf() failed, unmarshal json log message failed: %s", err)
+ }
+ if jl.Direction.To != exTo {
+ t.Errorf("Debugf() failed, expected message to: %s, got: %s", exTo, jl.Direction.To)
+ }
+ if jl.Direction.From != exFrom {
+ t.Errorf("Debugf() failed, expected message to: %s, got: %s", exFrom, jl.Direction.From)
+ }
+ if jl.Message != fmt.Sprintf(f, msg) {
+ t.Errorf("Debugf() failed, expected message: %s, got %s", msg, jl.Message)
+ }
+
+ b.Reset()
+ l.Infof(Log{Direction: DirClientToServer, Format: f, Messages: []interface{}{msg2}})
+ exFrom = "client"
+ exTo = "server"
+ jl, err = unmarshalLog(b.Bytes())
+ if err != nil {
+ t.Errorf("Debugf() failed, unmarshal json log message failed: %s", err)
+ }
+ if jl.Direction.To != exTo {
+ t.Errorf("Debugf() failed, expected message to: %s, got: %s", exTo, jl.Direction.To)
+ }
+ if jl.Direction.From != exFrom {
+ t.Errorf("Debugf() failed, expected message to: %s, got: %s", exFrom, jl.Direction.From)
+ }
+ if jl.Message != fmt.Sprintf(f, msg2) {
+ t.Errorf("Debugf() failed, expected message: %s, got %s", msg2, jl.Message)
+ }
+
+ b.Reset()
+ l.l = LevelWarn
+ l.Infof(Log{Direction: DirServerToClient, Format: "test %s", Messages: []interface{}{"foo"}})
+ if b.String() != "" {
+ t.Error("Info message was not expected to be logged")
+ }
+}
+
+func TestJSONWarnf(t *testing.T) {
+ var b bytes.Buffer
+ l := NewJSON(&b, LevelWarn)
+ f := "test %s"
+ msg := "foo"
+ msg2 := "bar"
+
+ l.Warnf(Log{Direction: DirServerToClient, Format: f, Messages: []interface{}{msg}})
+ exFrom := "server"
+ exTo := "client"
+ jl, err := unmarshalLog(b.Bytes())
+ if err != nil {
+ t.Errorf("Debugf() failed, unmarshal json log message failed: %s", err)
+ }
+ if jl.Direction.To != exTo {
+ t.Errorf("Debugf() failed, expected message to: %s, got: %s", exTo, jl.Direction.To)
+ }
+ if jl.Direction.From != exFrom {
+ t.Errorf("Debugf() failed, expected message to: %s, got: %s", exFrom, jl.Direction.From)
+ }
+ if jl.Message != fmt.Sprintf(f, msg) {
+ t.Errorf("Debugf() failed, expected message: %s, got %s", msg, jl.Message)
+ }
+
+ b.Reset()
+ l.Warnf(Log{Direction: DirClientToServer, Format: f, Messages: []interface{}{msg2}})
+ exFrom = "client"
+ exTo = "server"
+ jl, err = unmarshalLog(b.Bytes())
+ if err != nil {
+ t.Errorf("Debugf() failed, unmarshal json log message failed: %s", err)
+ }
+ if jl.Direction.To != exTo {
+ t.Errorf("Debugf() failed, expected message to: %s, got: %s", exTo, jl.Direction.To)
+ }
+ if jl.Direction.From != exFrom {
+ t.Errorf("Debugf() failed, expected message to: %s, got: %s", exFrom, jl.Direction.From)
+ }
+ if jl.Message != fmt.Sprintf(f, msg2) {
+ t.Errorf("Debugf() failed, expected message: %s, got %s", msg2, jl.Message)
+ }
+
+ b.Reset()
+ l.l = LevelError
+ l.Warnf(Log{Direction: DirServerToClient, Format: "test %s", Messages: []interface{}{"foo"}})
+ if b.String() != "" {
+ t.Error("Warn message was not expected to be logged")
+ }
+}
+
+func TestJSONErrorf(t *testing.T) {
+ var b bytes.Buffer
+ l := NewJSON(&b, LevelError)
+ f := "test %s"
+ msg := "foo"
+ msg2 := "bar"
+
+ l.Errorf(Log{Direction: DirServerToClient, Format: f, Messages: []interface{}{msg}})
+ exFrom := "server"
+ exTo := "client"
+ jl, err := unmarshalLog(b.Bytes())
+ if err != nil {
+ t.Errorf("Debugf() failed, unmarshal json log message failed: %s", err)
+ }
+ if jl.Direction.To != exTo {
+ t.Errorf("Debugf() failed, expected message to: %s, got: %s", exTo, jl.Direction.To)
+ }
+ if jl.Direction.From != exFrom {
+ t.Errorf("Debugf() failed, expected message to: %s, got: %s", exFrom, jl.Direction.From)
+ }
+ if jl.Message != fmt.Sprintf(f, msg) {
+ t.Errorf("Debugf() failed, expected message: %s, got %s", msg, jl.Message)
+ }
+
+ b.Reset()
+ l.Errorf(Log{Direction: DirClientToServer, Format: f, Messages: []interface{}{msg2}})
+ exFrom = "client"
+ exTo = "server"
+ jl, err = unmarshalLog(b.Bytes())
+ if err != nil {
+ t.Errorf("Debugf() failed, unmarshal json log message failed: %s", err)
+ }
+ if jl.Direction.To != exTo {
+ t.Errorf("Debugf() failed, expected message to: %s, got: %s", exTo, jl.Direction.To)
+ }
+ if jl.Direction.From != exFrom {
+ t.Errorf("Debugf() failed, expected message to: %s, got: %s", exFrom, jl.Direction.From)
+ }
+ if jl.Message != fmt.Sprintf(f, msg2) {
+ t.Errorf("Debugf() failed, expected message: %s, got %s", msg2, jl.Message)
+ }
+
+ b.Reset()
+ l.l = -99
+ l.Errorf(Log{Direction: DirServerToClient, Format: "test %s", Messages: []interface{}{"foo"}})
+ if b.String() != "" {
+ t.Error("Error message was not expected to be logged")
+ }
+}
+
+func unmarshalLog(j []byte) (jsonLog, error) {
+ var jl jsonLog
+ if err := json.Unmarshal(j, &jl); err != nil {
+ return jl, err
+ }
+ return jl, nil
+}