docs: 手动实现 simple log 日志库

simplelog/go.mod

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+module simplelog
+
+go 1.16

simplelog/simplelog.go

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+package simplelog
+
+import (
+	"fmt"
+	"io"
+	"os"
+	"runtime"
+	"time"
+)
+
+// 自定义日志
+
+type LogLevel struct {
+	s    string
+	flag LevelFlag
+}
+
+func (l LogLevel) String() string {
+	return l.s
+}
+
+type LevelFlag uint8
+
+const (
+	FlagInfo  LevelFlag = 0x1
+	FlagWarn  LevelFlag = 0x2
+	FlagError LevelFlag = 0x4
+	FlagDebug LevelFlag = 0x8
+)
+
+var (
+	INFO  = LogLevel{"INFO", FlagInfo}
+	WARN  = LogLevel{"WARN", FlagWarn}
+	ERROR = LogLevel{"ERROR", FlagError}
+	DEBUG = LogLevel{"DEBUG", FlagDebug}
+)
+
+// Logger 日志类
+type Logger struct {
+	w            io.Writer
+	timeFormat   string
+	loggerFormat string
+	flag         LevelFlag
+}
+
+func (l *Logger) time() string {
+	now := time.Now()
+	return now.Format(l.timeFormat)
+}
+
+func (l *Logger) PrintLog(level LogLevel, log string) {
+	// 根据 flag 位 限制日志级别
+	if l.flag&level.flag != level.flag {
+		return
+	}
+
+	pc, _, _, ok := runtime.Caller(2)
+	var f *runtime.Func
+	if ok {
+		f = runtime.FuncForPC(pc)
+		_, _ = fmt.Fprintf(l.w, l.loggerFormat, l.time(), level, pc, f.Name(), log)
+	} else {
+		_, _ = fmt.Fprintf(l.w, l.loggerFormat, l.time(), level, "--", "Unknown", log)
+	}
+}
+
+// Debug 调试输出
+func (l *Logger) Debug(log string) {
+	l.PrintLog(DEBUG, log)
+}
+
+// Info 消息输出
+func (l *Logger) Info(log string) {
+	l.PrintLog(INFO, log)
+}
+
+// Warn 消息输出
+func (l *Logger) Warn(log string) {
+	l.PrintLog(WARN, log)
+}
+
+// Error 消息输出
+func (l *Logger) Error(log string) {
+	l.PrintLog(ERROR, log)
+}
+
+// 函数式 选项模式
+
+type Option struct {
+	Writer     io.Writer
+	TimeFormat string
+	LogFormat  string
+	LevelFlag  LevelFlag
+}
+
+type OptionFunc func(*Option)
+
+func WithWriter(writer io.Writer) OptionFunc {
+	return func(option *Option) {
+		option.Writer = writer
+	}
+}
+
+func WithTimeFormat(timeFormat string) OptionFunc {
+	return func(option *Option) {
+		option.TimeFormat = timeFormat
+	}
+}
+
+func WithLogFormat(logFormat string) OptionFunc {
+	return func(option *Option) {
+		option.LogFormat = logFormat
+	}
+}
+
+func WithLogFlag(flag LevelFlag) OptionFunc {
+	return func(option *Option) {
+		option.LevelFlag = flag
+	}
+}
+
+// 默认参数
+var defaultOption = &Option{
+	Writer:     os.Stdout,
+	TimeFormat: "2006-01-02 15:04:05.99",
+	LogFormat:  "%-23s %s %v --- [%20s] : %s\n",
+	LevelFlag:  FlagInfo | FlagWarn | FlagError | FlagDebug,
+}
+
+func NewOption(opts ...OptionFunc) (opt *Option) {
+	opt = defaultOption
+	for _, o := range opts {
+		o(opt)
+	}
+	return
+}
+
+// NewLog 构造函数
+func NewLog(opts ...OptionFunc) *Logger {
+	opt := NewOption(opts...)
+
+	return &Logger{
+		w:            opt.Writer,
+		timeFormat:   opt.TimeFormat,
+		loggerFormat: opt.LogFormat,
+		flag:         opt.LevelFlag,
+	}
+}

simplelog/simplelog_test.go

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+package simplelog
+
+import (
+	"fmt"
+	"os"
+	"testing"
+	"time"
+)
+
+func TestLog(t *testing.T) {
+	log := NewLog()
+
+	log2 := NewLog(
+		WithWriter(os.Stdout),
+		WithTimeFormat("2006-01-02"),
+		WithLogFormat("%-10s %s %v %s =-=-> %s\n"),
+		WithLogFlag(FlagInfo|FlagDebug),
+	)
+
+	fmt.Printf("simpleLog => %#v\n", log)
+
+	fmt.Println("=========================================================")
+
+	for i := 0; i < 5; i++ {
+		log.Debug("测试 Debug 输出")
+		time.Sleep(100 * time.Millisecond)
+	}
+
+	fmt.Println("=========================================================")
+
+	for i := 0; i < 5; i++ {
+		log2.Debug("测试 Debug 输出")
+		time.Sleep(100 * time.Millisecond)
+	}
+}