feat: implement logger adapter (#67)

* feat: implement logger adapter

* improve test coverage

README.md

@@ -108,6 +108,19 @@ Implemented Jobs
 | Day of week  | YES       | 1-7 or SUN-SAT  | , - * ? /                  |
 | Year         | NO        | empty, 1970-    | , - * /                    |
 
+## Logger
+
+To set a custom logger, use the `logger.SetDefault` function.  
+The argument must implement the `logger.Logger` interface.
+
+The following example shows how to disable library logs.
+
+```go
+import "github.com/reugn/go-quartz/quartz/logger"
+
+logger.SetDefault(logger.NewSimpleLogger(nil, logger.LevelOff))
+```
+
 ## Examples
 
 ```go

quartz/job.go

@@ -10,6 +10,8 @@ import (
 	"strings"
 	"sync"
 	"sync/atomic"
+
+	"github.com/reugn/go-quartz/quartz/logger"
 )
 
 // Job represents an interface to be implemented by structs which represent a 'job'
@@ -188,6 +190,7 @@ type isolatedJob struct {
 // Execute is called by a Scheduler when the Trigger associated with this job fires.
 func (j *isolatedJob) Execute(ctx context.Context) {
 	if wasRunning := j.isRunning.Swap(true); wasRunning != nil && wasRunning.(bool) {
+		logger.Debugf("Executed job %d is running.", j.Job.Key())
 		return
 	}
 	defer j.isRunning.Store(false)

quartz/logger/default_logger.go

@@ -0,0 +1,80 @@
+package logger
+
+import (
+	"log"
+	"os"
+	"sync/atomic"
+)
+
+var defaultLogger atomic.Value
+
+func init() {
+	defaultLogger.Store(NewSimpleLogger(
+		log.New(os.Stdout, "", log.LstdFlags|log.Lshortfile), LevelInfo),
+	)
+}
+
+// Default returns the default Logger.
+func Default() Logger {
+	return defaultLogger.Load().(Logger)
+}
+
+// SetDefault makes l the default Logger.
+func SetDefault(l Logger) {
+	defaultLogger.Store(l)
+}
+
+// Trace logs at LevelTrace.
+func Trace(msg any) {
+	Default().Trace(msg)
+}
+
+// Tracef logs at LevelTrace.
+func Tracef(format string, args ...any) {
+	Default().Tracef(format, args...)
+}
+
+// Debug logs at LevelDebug.
+func Debug(msg any) {
+	Default().Debug(msg)
+}
+
+// Debugf logs at LevelDebug.
+func Debugf(format string, args ...any) {
+	Default().Debugf(format, args...)
+}
+
+// Info logs at LevelInfo.
+func Info(msg any) {
+	Default().Info(msg)
+}
+
+// Infof logs at LevelInfo.
+func Infof(format string, args ...any) {
+	Default().Infof(format, args...)
+}
+
+// Warn logs at LevelWarn.
+func Warn(msg any) {
+	Default().Warn(msg)
+}
+
+// Warnf logs at LevelWarn.
+func Warnf(format string, args ...any) {
+	Default().Warnf(format, args...)
+}
+
+// Error logs at LevelError.
+func Error(msg any) {
+	Default().Error(msg)
+}
+
+// Errorf logs at LevelError.
+func Errorf(format string, args ...any) {
+	Default().Errorf(format, args...)
+}
+
+// Enabled reports whether the logger handles records at the given level.
+func Enabled(level Level) bool {
+	return Default().Enabled(level)
+}

quartz/logger/level.go

@@ -0,0 +1,15 @@
+package logger
+
+// A Level is the importance or severity of a log event.
+// The higher the level, the more important or severe the event.
+type Level int
+
+// Names for common log levels.
+const (
+	LevelTrace Level = -8
+	LevelDebug Level = -4
+	LevelInfo  Level = 0
+	LevelWarn  Level = 4
+	LevelError Level = 8
+	LevelOff   Level = 12
+)

quartz/logger/logger.go

@@ -0,0 +1,38 @@
+package logger
+
+// A Logger handles log records.
+type Logger interface {
+
+	// Trace logs at LevelTrace.
+	Trace(msg any)
+
+	// Tracef logs at LevelTrace.
+	Tracef(format string, args ...any)
+
+	// Debug logs at LevelDebug.
+	Debug(msg any)
+
+	// Debugf logs at LevelDebug.
+	Debugf(format string, args ...any)
+
+	// Info logs at LevelInfo.
+	Info(msg any)
+
+	// Infof logs at LevelInfo.
+	Infof(format string, args ...any)
+
+	// Warn logs at LevelWarn.
+	Warn(msg any)
+
+	// Warnf logs at LevelWarn.
+	Warnf(format string, args ...any)
+
+	// Error logs at LevelError.
+	Error(msg any)
+
+	// Errorf logs at LevelError.
+	Errorf(format string, args ...any)
+
+	// Enabled reports whether the logger handles records at the given level.
+	Enabled(level Level) bool
+}

quartz/logger/logger_test.go

@@ -0,0 +1,122 @@
+package logger_test
+
+import (
+	"bytes"
+	"io"
+	"log"
+	"strings"
+	"testing"
+
+	"github.com/reugn/go-quartz/quartz/logger"
+)
+
+func TestSimpleLogger(t *testing.T) {
+	var b bytes.Buffer
+	stdLogger := log.New(&b, "", log.LstdFlags)
+	logger.SetDefault(logger.NewSimpleLogger(stdLogger, logger.LevelInfo))
+
+	logger.Trace("Trace")
+	assertEmpty(&b, t)
+	logger.Tracef("Trace%s", "f")
+	assertEmpty(&b, t)
+
+	logger.Debug("Debug")
+	assertEmpty(&b, t)
+	logger.Debugf("Debug%s", "f")
+	assertEmpty(&b, t)
+
+	logger.Info("Info")
+	assertNotEmpty(&b, t)
+	logger.Infof("Info%s", "f")
+	assertNotEmpty(&b, t)
+
+	logger.Warn("Warn")
+	assertNotEmpty(&b, t)
+	logger.Warnf("Warn%s", "f")
+	assertNotEmpty(&b, t)
+
+	logger.Error("Error")
+	assertNotEmpty(&b, t)
+	logger.Errorf("Error%s", "f")
+	assertNotEmpty(&b, t)
+}
+
+func TestLoggerOff(t *testing.T) {
+	var b bytes.Buffer
+	stdLogger := log.New(&b, "", log.LstdFlags)
+	logger.SetDefault(logger.NewSimpleLogger(stdLogger, logger.LevelOff))
+
+	if logger.Enabled(logger.LevelError) {
+		t.Fatal("LevelError is enabled")
+	}
+	logger.Error("Error")
+	assertEmpty(&b, t)
+	logger.Errorf("Error%s", "f")
+	assertEmpty(&b, t)
+}
+
+func TestLogFormat(t *testing.T) {
+	var b bytes.Buffer
+	stdLogger := log.New(&b, "", log.LstdFlags)
+	logr := logger.NewSimpleLogger(stdLogger, logger.LevelTrace)
+	logger.SetDefault(logr)
+
+	empty := struct{}{}
+	logr.Trace("Trace")
+	assertNotEmpty(&b, t)
+	logr.Tracef("Tracef: %s, %d, %v, %v", "a", 1, true, empty)
+	checkLogFormat(&b, t)
+	logger.Tracef("Tracef: %s, %d, %v, %v", "a", 1, true, empty)
+	checkLogFormat(&b, t)
+
+	logr.Debug("Debug")
+	assertNotEmpty(&b, t)
+	logr.Debugf("Debugf: %s, %d, %v, %v", "a", 1, true, empty)
+	checkLogFormat(&b, t)
+	logger.Debugf("Debugf: %s, %d, %v, %v", "a", 1, true, empty)
+	checkLogFormat(&b, t)
+
+	logr.Infof("Infof: %s, %d, %v, %v", "a", 1, true, empty)
+	checkLogFormat(&b, t)
+	logger.Infof("Infof: %s, %d, %v, %v", "a", 1, true, empty)
+	checkLogFormat(&b, t)
+
+	logr.Warnf("Warnf: %s, %d, %v, %v", "a", 1, true, empty)
+	checkLogFormat(&b, t)
+	logger.Warnf("Warnf: %s, %d, %v, %v", "a", 1, true, empty)
+	checkLogFormat(&b, t)
+
+	logr.Errorf("Errorf: %s, %d, %v, %v", "a", 1, true, empty)
+	checkLogFormat(&b, t)
+	logger.Errorf("Errorf: %s, %d, %v, %v", "a", 1, true, empty)
+	checkLogFormat(&b, t)
+}
+
+func assertEmpty(r io.Reader, t *testing.T) {
+	logMsg := readAll(r, t)
+	if logMsg != "" {
+		t.Fatalf("Log msg is not empty: %s", logMsg)
+	}
+}
+
+func assertNotEmpty(r io.Reader, t *testing.T) {
+	logMsg := readAll(r, t)
+	if logMsg == "" {
+		t.Fatal("Log msg is empty")
+	}
+}
+
+func checkLogFormat(r io.Reader, t *testing.T) {
+	logMsg := readAll(r, t)
+	if !strings.Contains(logMsg, "a, 1, true, {}") {
+		t.Fatalf("Invalid log format: %s", logMsg)
+	}
+}
+
+func readAll(r io.Reader, t *testing.T) string {
+	bytes, err := io.ReadAll(r)
+	if err != nil {
+		t.Fatal(err)
+	}
+	return string(bytes)
+}