## quick start 不是很严格的情况下使用`SugaredLogger` ``` logger, _ := zap.NewProduction() defer logger.Sync() // flushes buffer, if any sugar := logger.Sugar() sugar.Infow("failed to fetch URL", // Structured context as loosely typed key-value pairs. "url", url, "attempt", 3, "backoff", time.Second, ) sugar.Infof("Failed to fetch URL: %s", url) ``` 需要类型安全时 使用`Logger` ``` logger, _ := zap.NewProduction() defer logger.Sync() logger.Info("failed to fetch URL", // Structured context as strongly typed Field values. zap.String("url", url), zap.Int("attempt", 3), zap.Duration("backoff", time.Second), ) ``` ## 项目使用 ``` package main import ( "go.uber.org/zap" "encoding/json" ) func main() { rawJSON := []byte(`{ "level": "debug", "encoding": "json", "outputPaths": ["stdout", "./demo.log"], "errorOutputPaths": ["stderr"], "initialFields": {"foo": "bar"}, "encoderConfig": { "messageKey": "message", "levelKey": "level", "levelEncoder": "lowercase" } }`) var cfg zap.Config if err := json.Unmarshal(rawJSON, &cfg); err != nil { panic(err) } logger, err := cfg.Build() if err != nil { panic(err) } defer logger.Sync() logger.Info("logger construction succeeded") } ``` ## 在其他文件使用该logger 其他文件需要setlogger方法 ``` package demo import ( "go.uber.org/zap") var logger *zap.Logger func SetLogger(l *zap.Logger) { logger = l logger.Named("history") } func LogInOtherFile() { logger.Info("log in demo", zap.String("user", "cc")) } ``` 在logger初始化后调用setlogger ``` package main import ( "go.uber.org/zap" "encoding/json" "demo/demo" ) func main() { rawJSON := []byte(`{ "level": "debug", "encoding": "json", "outputPaths": ["stdout", "./demo.log"], "errorOutputPaths": ["stderr"], "initialFields": {}, "encoderConfig": { "messageKey": "message", "levelKey": "level", "levelEncoder": "lowercase" } }`) var cfg zap.Config if err := json.Unmarshal(rawJSON, &cfg); err != nil { panic(err) } logger, err := cfg.Build() if err != nil { panic(err) } defer logger.Sync() logger.Info("logger construction succeeded") demo.SetLogger(logger) demo.LogInOtherFile() } ``` ## 更方便的调用 牺牲性能为代价,增强可用性: ``` //Sugar wraps the Logger to provide a more ergonomic, but slightly slower, //API. Sugaring a Logger is quite inexpensive, so it's reasonable for a //single application to use both Loggers and SugaredLoggers, converting //between them on the boundaries of performance-sensitive code. s := logger.Sugar() s.Info("Use config file: ", ".demo.log") s.Info("Config: ", cfg) ``` ## 结合cobra来使用 logger初始化放在cobra的initConfig中: ``` func initConfig() { ..... ..... ..... // init logger initLogger() } ``` defer 放在cobra的Execute中: ``` func Execute() { if logger != nil { defer logger.Sync() } if err := RootCmd.Execute(); err != nil { fmt.Println(err) os.Exit(1) } } ``` ## NewDevelopment和NewProduction区别 zap.NewDevelopment() 包含代码中文件信息 ``` 2018-01-18T15:40:05.991+0800 INFO tool/zaplog.go:83 to sugar failed to fetch URLurlhttp://example.comattempt3backoff1s 2018-01-18T15:40:05.991+0800 INFO tool/zaplog.go:88 to sugar failed to fetch URL {"url": "http://example.com", "attempt": 3, "backoff": "1s"} 2018-01-18T15:40:05.991+0800 INFO tool/zaplog.go:94 to desugar failed to fetch URL {"url": "http://example.com", "attempt": 3, "backoff": "1s"} ``` zap.NewProduction() 去除了文件信息 ``` {"level":"info","ts":1516261205.991458,"caller":"tool/zaplog.go:109","msg":"to sugar failed to fetch URLurlhttp://example.comattempt3backoff1s"} {"level":"info","ts":1516261205.9914737,"caller":"tool/zaplog.go:114","msg":"to sugar failed to fetch URL","url":"http://example.com","attempt":3,"backoff":1} ```