简明教程：通过Go语言实现简单日志分析器

package main

import (
    "bufio"
    "fmt"
    "os"
    "regexp"
)

func main() {
    file, err := os.Open("example.log")
    if err != nil {
        fmt.Println("Error opening file:", err)
        return
    }
    defer file.Close()

    reader := bufio.NewReader(file)
    for {
        line, err := reader.ReadString('\n')
        if err != nil {
            break // 结束读取
        }
        // 处理每一行日志
        processLogLine(line)
    }
}

func processLogLine(line string) {
    // 这里进行日志行的处理，例如提取信息
    fmt.Println(line)
}

// 在processLogLine函数中加入正则表达式提取
func processLogLine(line string) {
    re := regexp.MustCompile(`\[(.*?)\]\s(.*?):\s(.*)`) // 提取时间戳、日志级别和消息
    match := re.FindStringSubmatch(line)
    if len(match) > 0 {
        timestamp := match[1]
        logLevel := match[2]
        message := match[3]

        fmt.Printf("Timestamp: %s, Level: %s, Message: %s\n", timestamp, logLevel, message)
    }
}

package main

import (
    "fmt"
    "io"
    "os"
)

const bufferSize = 4096

func main() {
    file, err := os.Open("large.log")
    if err != nil {
        fmt.Println("Error opening file:", err)
        return
    }
    defer file.Close()

    buffer := make([]byte, bufferSize)
    for {
        bytesRead, err := file.Read(buffer)
        if err != nil {
            if err != io.EOF {
                fmt.Println("Error reading file:", err)
            }
            break
        }
        // 处理读取到的数据块
        processBuffer(buffer[:bytesRead])
    }
}

func processBuffer(buffer []byte) {
    // 在这里处理buffer中的数据，例如分割成行
    fmt.Println(string(buffer))
}

package main

import (
    "bufio"
    "fmt"
    "os"
)

func main() {
    file, err := os.Open("large.log")
    if err != nil {
        fmt.Println("Error opening file:", err)
        return
    }
    defer file.Close()

    scanner := bufio.NewScanner(file)
    for scanner.Scan() {
        line := scanner.Text()
        // 处理每一行
        processLine(line)
    }

    if err := scanner.Err(); err != nil {
        fmt.Println("Error scanning file:", err)
    }
}

func processLine(line string) {
    // 处理单行日志
    fmt.Println(line)
}

package main

import (
    "fmt"
    "regexp"
)

func main() {
    logLine := "[2023-10-27 10:00:00] INFO: This is a log message."
    re := regexp.MustCompile(`\[(.*?)\]\s(.*?):\s(.*)`)
    match := re.FindStringSubmatch(logLine)

    if len(match) > 0 {
        timestamp := match[1]
        logLevel := match[2]
        message := match[3]

        fmt.Printf("Timestamp: %s, Level: %s, Message: %s\n", timestamp, logLevel, message)
    }
}

package main

import (
    "fmt"
    "regexp"
)

func main() {
    logLine := "192.168.1.1 - - [27/Oct/2023:10:00:00 +0000] \"GET /index.html HTTP/1.1\" 200 1234"
    re := regexp.MustCompile(`(\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}).*?"(GET|POST)\s(.*?)\sHTTP`)
    match := re.FindStringSubmatch(logLine)

    if len(match) > 0 {
        ipAddress := match[1]
        requestMethod := match[2]
        requestPath := match[3]

        fmt.Printf("IP Address: %s, Method: %s, Path: %s\n", ipAddress, requestMethod, requestPath)
    }
}

package main

import (
    "fmt"
    "regexp"
)

func main() {
    logLine := "ERROR: [Error Code: 500] Internal Server Error"
    re := regexp.MustCompile(`ERROR:\s\[Error Code:\s(\d+)\]\s(.*?)$`)
    match := re.FindStringSubmatch(logLine)

    if len(match) > 0 {
        errorCode := match[1]
        errorMessage := match[2]

        fmt.Printf("Error Code: %s, Message: %s\n", errorCode, errorMessage)
    }
}

package main

import (
    "fmt"
    "regexp"
    "sync"
)

var (
    rePool sync.Pool
)

func init() {
    rePool = sync.Pool{
        New: func() interface{} {
            re, err := regexp.Compile(`\[(.*?)\]\s(.*?):\s(.*)`)
            if err != nil {
                panic(err) // 处理编译错误
            }
            return re
        },
    }
}

func processLogLine(line string) {
    re := rePool.Get().(*regexp.Regexp)
    defer rePool.Put(re)

    match := re.FindStringSubmatch(line)
    if len(match) > 0 {
        timestamp := match[1]
        logLevel := match[2]
        message := match[3]

        fmt.Printf("Timestamp: %s, Level: %s, Message: %s\n", timestamp, logLevel, message)
    }
}

func main() {
    // 示例调用
    processLogLine("[2023-10-27 10:00:00] INFO: This is a log message.")
}