Log 门面接口

// log/log.go
type Level int

const (
    LevelDebug Level = iota
    LevelInfo
    LevelWarn
    LevelError
    LevelFatal
)

type Logger interface {
    Log(level Level, msg string, fields ...Field)
    Enabled(level Level) bool
    With(fields ...Field) Logger
}

type Field struct {
    Key   string
    Value interface{}
}

import "github.com/tx7do/go-wind/log"

func main() {
    log.Info("service started", log.String("addr", ":8080"))
    log.Error("connection failed", log.Err(err))
    log.Debug("debug info", log.Int("count", 42))
}

log.String("key", "value")
log.Int("count", 42)
log.Float64("ratio", 0.95)
log.Bool("enabled", true)
log.Err(err)
log.Duration("elapsed", time.Since(start))
log.Any("data", customValue)

logger := log.With(log.String("service", "order"), log.String("trace_id", traceID))
logger.Info("processing order")     // 自动携带 service 和 trace_id
logger.Error("order failed", log.Err(err))

// log/global.go
var global Logger = &nopLogger{}

func SetLogger(l Logger) {
    global = l
}

func Default() Logger {
    return global
}

// go-wind-plugins/log/zap/logger.go
func init() {
    log.SetLogger(NewZapLogger())
}

type nopLogger struct{}

func (n *nopLogger) Log(level Level, msg string, fields ...Field) {}
func (n *nopLogger) Enabled(level Level) bool { return false }
func (n *nopLogger) With(fields ...Field) Logger { return n }