序
本文主要研究一下zerolog的Level
Level
github.com/rs/zerolog@v1.20.0/log.go
代码语言：javascript复制// Level defines log levels.
type Level int8
const (
// DebugLevel defines debug log level.
DebugLevel Level = iota
// InfoLevel defines info log level.
InfoLevel
// WarnLevel defines warn log level.
WarnLevel
// ErrorLevel defines error log level.
ErrorLevel
// FatalLevel defines fatal log level.
FatalLevel
// PanicLevel defines panic log level.
PanicLevel
// NoLevel defines an absent log level.
NoLevel
// Disabled disables the logger.
Disabled
// TraceLevel defines trace log level.
TraceLevel Level = -1
)
func (l Level) String() string {
switch l {
case TraceLevel:
return "trace"
case DebugLevel:
return "debug"
case InfoLevel:
return "info"
case WarnLevel:
return "warn"
case ErrorLevel:
return "error"
case FatalLevel:
return "fatal"
case PanicLevel:
return "panic"
case NoLevel:
return ""
}
return ""
}
Level为int8类型，其中trace最小为-1，之后是debug、info、warn、error、fatal、panic、NoLevel及Disabled
log.Level
github.com/rs/zerolog@v1.20.0/log.go
代码语言：javascript复制func Trace() *zerolog.Event {
return Logger.Trace()
}
func Debug() *zerolog.Event {
return Logger.Debug()
}
func Info() *zerolog.Event {
return Logger.Info()
}
func Warn() *zerolog.Event {
return Logger.Warn()
}
func Error() *zerolog.Event {
return Logger.Error()
}
func Fatal() *zerolog.Event {
return Logger.Fatal()
}
func Panic() *zerolog.Event {
return Logger.Panic()
}
log.go提供了Trace、Debug、Info、Warn、Error、Fatal、Panic方法来创建
*zerolog.Event
logger.newEvent
github.com/rs/zerolog@v1.20.0/log.go
代码语言：javascript复制func (l *Logger) Trace() *Event {
return l.newEvent(TraceLevel, nil)
}
func (l *Logger) Debug() *Event {
return l.newEvent(DebugLevel, nil)
}
func (l *Logger) Warn() *Event {
return l.newEvent(WarnLevel, nil)
}
func (l *Logger) Error() *Event {
return l.newEvent(ErrorLevel, nil)
}
func (l *Logger) Fatal() *Event {
return l.newEvent(FatalLevel, func(msg string) { os.Exit(1) })
}
func (l *Logger) Panic() *Event {
return l.newEvent(PanicLevel, func(msg string) { panic(msg) })
}
func (l *Logger) newEvent(level Level, done func(string)) *Event {
enabled := l.should(level)
if !enabled {
return nil
}
e := newEvent(l.w, level)
e.done = done
e.ch = l.hooks
if level != NoLevel {
e.Str(LevelFieldName, LevelFieldMarshalFunc(level))
}
if l.context != nil && len(l.context) > 1 {
e.buf = enc.AppendObjectData(e.buf, l.context)
}
return e
}
newEvent方法首先判断当前logger是否允许指定的level，不允许则直接返回nil；允许的话则通过event包的newEvent来新建event，设置done、hooks
event.newEvent
github.com/rs/zerolog@v1.20.0/event.go
代码语言：javascript复制func newEvent(w LevelWriter, level Level) *Event {
e := eventPool.Get().(*Event)
e.buf = e.buf[:0]
e.ch = nil
e.buf = enc.AppendBeginMarker(e.buf)
e.w = w
e.level = level
e.stack = false
return e
}
newEvent方法从eventPool获取一个Event，然后重置一下其属性
WithLevel
github.com/rs/zerolog@v1.20.0/log/log.go
代码语言：javascript复制func WithLevel(level zerolog.Level) *zerolog.Event {
return Logger.WithLevel(level)
}
func (l *Logger) WithLevel(level Level) *Event {
switch level {
case TraceLevel:
return l.Trace()
case DebugLevel:
return l.Debug()
case InfoLevel:
return l.Info()
case WarnLevel:
return l.Warn()
case ErrorLevel:
return l.Error()
case FatalLevel:
return l.newEvent(FatalLevel, nil)
case PanicLevel:
return l.newEvent(PanicLevel, nil)
case NoLevel:
return l.Log()
case Disabled:
return nil
default:
panic("zerolog: WithLevel(): invalid level: " strconv.Itoa(int(level)))
}
}
WithLevel可以动态传入Level，然后返回指定level的event
SetGlobalLevel
github.com/rs/zerolog@v1.20.0/ctx.go
代码语言：javascript复制func init() {
SetGlobalLevel(TraceLevel)
l := Nop()
disabledLogger = &l
}
默认是TraceLevel
实例
代码语言：javascript复制func withLevelDemo() {
log.WithLevel(zerolog.TraceLevel).Msg("trace level")
log.WithLevel(zerolog.DebugLevel).Msg("debug level")
log.WithLevel(zerolog.InfoLevel).Msg("info level")
}
输出
代码语言：javascript复制{"level":"trace","time":"2021-01-03T20:59:42 08:00","message":"trace level"}
{"level":"debug","time":"2021-01-03T20:59:42 08:00","message":"debug level"}
{"level":"info","time":"2021-01-03T20:59:42 08:00","message":"info level"}
小结
Level为int8类型，其中trace最小为-1，之后是debug、info、warn、error、fatal、panic、NoLevel及Disabled；log.go提供了Trace、Debug、Info、Warn、Error、Fatal、Panic方法来创建*zerolog.Event；WithLevel可以动态传入Level，然后返回指定level的event。
doc
- zerolog
