With 注入通用属性

时可以用With方法为 logger 添加通用属性。这些属性会自动附加到每条日志记录中适合注入服务名、环境、版本等上下文信息。package main import ( fmt log/slog os time ) func main() { jsonLogger : slog.New(slog.NewJSONHandler(os.Stderr, slog.HandlerOptions{ AddSource: true, Level: slog.LevelDebug, ReplaceAttr: func(groups []string, a slog.Attr) slog.Attr { if a.Key slog.TimeKey { if t, ok : a.Value.Any().(time.Time); ok { a.Value slog.StringValue(t.Format(time.RFC3339)) } } if a.Key slog.SourceKey { source : a.Value.Any().(*slog.Source) shortFile : source.File for i : len(source.File) - 1; i 0; i-- { if source.File[i] / { shortFile source.File[i1:] break } } return slog.String(source, fmt.Sprintf(%s:%d, shortFile, source.Line)) } return a }, })).With(logger, json, env, production) jsonLogger.Debug(Hello world) jsonLogger.Info(Hello world) jsonLogger.Warn(Hello world) jsonLogger.Error(Hello world) jsonLogger.Info(this is a message, name, zhangsan) }运行输出$ go run main.go {time:2026-02-15T13:24:3808:00,level:DEBUG,source:main.go:42,msg:Hello world,logger:json,env:production} {time:2026-02-15T13:24:3808:00,level:INFO,source:main.go:43,msg:Hello world,logger:json,env:production} {time:2026-02-15T13:24:3808:00,level:WARN,source:main.go:44,msg:Hello world,logger:json,env:production} {time:2026-02-15T13:24:3808:00,level:ERROR,source:main.go:45,msg:Hello world,logger:json,env:production} {time:2026-02-15T13:24:3808:00,level:INFO,source:main.go:47,msg:this is a message,logger:json,env:production,name:zhangsan}使用 Group 对属性分组当日志属性较多时可以使用slog.Group将相关属性组织在一起使输出结构更清晰package main import ( fmt log/slog os time ) func main() { jsonLogger : slog.New(slog.NewJSONHandler(os.Stderr, slog.HandlerOptions{ AddSource: true, Level: slog.LevelDebug, ReplaceAttr: func(groups []string, a slog.Attr) slog.Attr { if a.Key slog.TimeKey { if t, ok : a.Value.Any().(time.Time); ok { a.Value slog.StringValue(t.Format(time.RFC3339)) } } if a.Key slog.SourceKey { source : a.Value.Any().(*slog.Source) shortFile : source.File for i : len(source.File) - 1; i 0; i-- { if source.File[i] / { shortFile source.File[i1:] break } } return slog.String(source, fmt.Sprintf(%s:%d, shortFile, source.Line)) } return a }, })) jsonLogger jsonLogger.With(logger, json) // 使用 Group 组织相关属性 jsonLogger.Info(系统状态, slog.Group(metrics, slog.Int(cpu, 4), slog.Float64(memPercent, 2.33), ), slog.Group(request, slog.String(method, GET), slog.String(path, /api/users), ), ) }运行输出$ go run main.go {time:2026-02-15T13:30:0808:00,level:INFO,source:main.go:43,msg:系统状态,logger:json,metrics:{cpu:4,memPercent:2.33},request:{method:GET,path:/api/users}}高性能场景使用 LogAttrs如果需要在高性能循环中打印日志建议使用LogAttrs方法。它使用强类型属性slog.Attr避免了反射带来的性能开销。package main import ( context log/slog os time ) func main() { jsonLogger : slog.New(slog.NewJSONHandler(os.Stderr, slog.HandlerOptions{ AddSource: true, Level: slog.LevelDebug, ReplaceAttr: func(groups []string, a slog.Attr) slog.Attr { if a.Key slog.TimeKey { if t, ok : a.Value.Any().(time.Time); ok { a.Value slog.StringValue(t.Format(time.RFC3339)) } } if a.Key slog.SourceKey { source : a.Value.Any().(*slog.Source) shortFile : source.File for i : len(source.File) - 1; i 0; i-- { if source.File[i] / { shortFile source.File[i1:] break } } return slog.String(source, fmt.Sprintf(%s:%d, shortFile, source.Line)) } return a }, })).With(logger, json) for i : range 5 { jsonLogger.LogAttrs( context.Background(), slog.LevelInfo, 执行遍历, slog.Int(round, i), slog.String(task_name, cleanup), slog.Duration(duration, time.Second*time.Duration(i1)), ) } }运行输出$ go run main.go {time:2026-02-15T13:38:2108:00,level:INFO,source:main.go:45,msg:执行遍历,logger:json,round:0,task_name:cleanup,duration:1000000000} {time:2026-02-15T13:38:2108:00,level:INFO,source:main.go:45,msg:执行遍历,logger:json,round:1,task_name:cleanup,duration:2000000000} {time:2026-02-15T13:38:2108:00,level:INFO,source:main.go:45,msg:执行遍历,logger:json,round:2,task_name:cleanup,duration:3000000000} {time:2026-02-15T13:38:2108:00,level:INFO,source:main.go:45,msg:执行遍历,logger:json,round:3,task_name:cleanup,duration:4000000000} {time:2026-02-15T13:38:2108:00,level:INFO,source:main.go:45,msg:执行遍历,logger:json,round:4,task_name:cleanup,duration:5000000000}性能对比根据官方基准测试LogAttrs相比普通方法调用有约 30% 的性能提升