How to deal with file system access permission issues for concurrent files in Go language?

How to deal with file system access permission issues for concurrent files in Go language?

In concurrent programming, dealing with file system access permissions is an important issue. In the Go language, we can use mutex locks (Mutex) and read-write locks (RWMutex) to implement concurrent access control to files. This article will introduce how to use mutex locks and read-write locks to handle file system access issues for concurrent files, and provide corresponding code examples.

Mutex (Mutex)

Mutex (Mutex) is the simplest concurrency control mechanism, which only allows one process or thread to access shared resources. In Go language, you can use mutex locks to achieve exclusive access to files.

The following is a sample code that uses a mutex to handle concurrent file access:

package main

import (
    "fmt"
    "os"
    "sync"
)

var (
    fileMutex sync.Mutex
)

func writeFile(filename string, data string) {
    fileMutex.Lock()
    defer fileMutex.Unlock()

    file, err := os.OpenFile(filename, os.O_WRONLY|os.O_CREATE|os.O_APPEND, 0666)
    if err != nil {
        fmt.Println("Failed to open file:", err)
        return
    }
    defer file.Close()

    _, err = file.WriteString(data + "
")
    if err != nil {
        fmt.Println("Failed to write to file:", err)
        return
    }
}

func main() {
    go writeFile("file1.txt", "Content for file 1")
    go writeFile("file2.txt", "Content for file 2")

    // Wait for goroutines to finish
    time.Sleep(time.Second)
}

In the above code, we define a mutex (fileMutex) for locking files Access. In the writeFile function, first use the fileMutex.Lock() statement to lock access to the file, and then use defer fileMutex.Unlock() to unlock it at the end of the function File access.

In the main function, we use two goroutines to call the writeFile function respectively to write content to two different files. By using a mutex, we ensure that access to each file is exclusive and avoid concurrent access conflicts.

Read-write lock (RWMutex)

Read-write lock (RWMutex) is a more advanced concurrency control mechanism that allows multiple processes or threads to access shared resources at the same time when reading operations , but only one is allowed to access during a write operation. In the Go language, you can use read-write locks to achieve concurrent read-write control of files.

The following is a sample code that uses a read-write lock to handle concurrent file access permissions:

package main

import (
    "fmt"
    "os"
    "sync"
)

var (
    fileLock sync.RWMutex
)

func readFile(filename string) {
    fileLock.RLock()
    defer fileLock.RUnlock()

    file, err := os.Open(filename)
    if err != nil {
        fmt.Println("Failed to open file:", err)
        return
    }
    defer file.Close()

    data := make([]byte, 1024)
    _, err = file.Read(data)
    if err != nil {
        fmt.Println("Failed to read from file:", err)
        return
    }

    fmt.Println(string(data))
}

func writeFile(filename string, data string) {
    fileLock.Lock()
    defer fileLock.Unlock()

    file, err := os.OpenFile(filename, os.O_WRONLY|os.O_CREATE|os.O_APPEND, 0666)
    if err != nil {
        fmt.Println("Failed to open file:", err)
        return
    }
    defer file.Close()

    _, err = file.WriteString(data + "
")
    if err != nil {
        fmt.Println("Failed to write to file:", err)
        return
    }
}

func main() {
    go readFile("file1.txt")
    go writeFile("file2.txt", "Content for file 2")

    // Wait for goroutines to finish
    time.Sleep(time.Second)
}

In the above code, we define a read-write lock (fileLock) to control the Read and write access to files. In the readFile function, use the fileLock.RLock() statement to lock read access to the file, and then use defer fileLock.RUnlock() to unlock it at the end of the function Read access to the file. In the writeFile function, we use the fileLock.Lock() statement to lock the file for write access, and then use defer fileLock.Unlock() at the end of the function Unlocks the file for write access.

In the main function, we use two goroutines to call the readFile and writeFile functions respectively to achieve concurrent reading and writing of different files. By using read-write locks, we allow multiple goroutines to read the file contents at the same time, but only allow one goroutine to write, ensuring concurrent access control to the file.

The above is a sample code and explanation of using mutex locks and read-write locks to handle file system access permission issues for concurrent files. By properly using these concurrency control mechanisms, we can achieve safe concurrent access to files in the Go language.

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