Golang的log库如何配置日志输出 设置日志前缀与输出位置

package main

import (
    "log"
    "os"
)

func main() {
    // 设置日志前缀
    log.SetPrefix("[MY_APP] ")

    // 设置日志输出到文件
    file, err := os.OpenFile("app.log", os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0666)
    if err != nil {
        log.Fatal(err)
    }
    defer file.Close()

    log.SetOutput(file)

    // 记录日志
    log.Println("This is a log message.")
    log.Printf("This is a formatted log message: %d", 123)
}

package main

import (
    "log"
    "os"
)

func main() {
    // 创建一个自定义的logger
    file, err := os.OpenFile("app.log", os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0666)
    if err != nil {
        log.Fatal(err)
    }
    defer file.Close()

    logger := log.New(file, "[CUSTOM_APP] ", log.Ldate|log.Ltime|log.Lshortfile)

    // 使用自定义的logger记录日志
    logger.Println("This is a custom log message.")
    logger.Printf("This is a formatted custom log message: %d", 456)
}

package main

import (
    "os"

    "github.com/sirupsen/logrus"
)

func main() {
    // 创建一个logrus logger
    logger := logrus.New()

    // 设置日志级别
    logger.SetLevel(logrus.DebugLevel)

    // 设置日志格式为JSON
    logger.SetFormatter(&logrus.JSONFormatter{})

    // 设置日志输出到文件
    file, err := os.OpenFile("app.log", os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0666)
    if err != nil {
        logger.Fatal(err)
    }
    defer file.Close()
    logger.SetOutput(file)

    // 记录日志
    logger.WithFields(logrus.Fields{
        "animal": "walrus",
        "size":   10,
    }).Info("A walrus appears")

    logger.Debug("Useful debugging information.")
    logger.Warn("Something not ideal happened.")
    logger.Error("Something went wrong.")
}

package main

import (
    "os"

    "go.uber.org/zap"
    "go.uber.org/zap/zapcore"
)

func main() {
    // 创建一个zap logger
    config := zap.NewProductionEncoderConfig()
    config.EncodeTime = zapcore.ISO8601TimeEncoder
    file, _ := os.OpenFile("app.log", os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0666)
    core := zapcore.NewCore(
        zapcore.NewJSONEncoder(config),
        zapcore.AddSync(file),
        zap.DebugLevel,
    )
    logger := zap.New(core)
    defer logger.Sync() // flushes buffer, if any
    sugar := logger.Sugar()

    // 记录日志
    sugar.Infow("failed to fetch URL",
        "url", "http://example.com",
        "attempt", 3,
    )

    sugar.Debug("Useful debugging information.")
    sugar.Warn("Something not ideal happened.")
    sugar.Error("Something went wrong.")
}