File system, multi-threading, signal processing in Go language

With the continuous advancement and development of computer technology, more and more programming languages ​​​​are emerging. Among them, the Go language is favored by more and more developers and enterprises due to its powerful concurrency capabilities, garbage collection mechanism and other characteristics. attention and widespread application. Among them, file system, multi-threading and signal processing are some of the more important features in Go language. This article will detail the principles and applications of these features.

1. File system

Go language provides interfaces related to file operations through the os package. For example, the os package provides the File structure to represent files, and provides methods such as Open and Create to open and create files. It also provides methods such as Close, Stat, Read, and Write to operate files. The code is as follows:

package main

import (
    "fmt"
    "os"
)

func main() {
    file, err := os.Create("test.txt")
    if err != nil {
        panic(err)
    }
    defer file.Close()
    file.Write([]byte("hello world
"))
    file.Sync()

    file, err = os.Open("test.txt")
    if err != nil {
        panic(err)
    }
    defer file.Close()
    data := make([]byte, 100)
    count, err := file.Read(data)
    if err != nil {
        panic(err)
    }
    fmt.Printf("read %d bytes from file: %s", count, data)
}

In the above code, we created and opened a file named test.txt through the os package, and wrote a line of string "hello world" to it, and then cached The data in is synchronized to the file. Then, we reopen the file, read its contents, and print them out. It should be noted that we use the defer statement to ensure that the file is closed at the end of the function to avoid resource leaks.

In addition, the Go language also provides the path package and the filepath package to handle file path-related issues. For example, the path package provides methods such as Join, Dir, and Base to handle path strings, while the filepath package provides methods such as Clean, Join, and Split to handle issues such as path separators under different operating systems.

2. Multi-threading

The Go language provides powerful concurrent programming capabilities in the form of goroutines and channels. Coroutines are lightweight threads that can be easily created and destroyed, and their context switching cost is very small, thus supporting the creation and running of a large number of coroutines. Channels are the basic mechanism for communication between coroutines, allowing them to transfer and share data without locks. The code is as follows:

package main

import (
    "fmt"
    "time"
)

func worker(id int, jobs <-chan int, results chan<- int) {
    for j := range jobs {
        fmt.Printf("worker %d started job %d
", id, j)
        time.Sleep(time.Second)
        fmt.Printf("worker %d finished job %d
", id, j)
        results <- j * 2
    }
}

func main() {
    jobs := make(chan int, 100)
    results := make(chan int, 100)

    for w := 1; w <= 3; w++ {
        go worker(w, jobs, results)
    }

    for j := 1; j <= 9; j++ {
        jobs <- j
    }
    close(jobs)

    for a := 1; a <= 9; a++ {
        <-results
    }
}

In the above code, we define a work coroutine worker, which reads tasks from the jobs channel, executes the tasks, and then writes the results to the results channel. We created three work coroutines through loops and passed in the jobs and results channels as parameters. Next, we put 9 tasks into the jobs channel and read the results from results when the tasks are completed. It should be noted that we use the close statement to close the jobs channel to tell the worker coroutine that there are no more tasks to be executed.

In addition, the Go language also provides mechanisms such as mutex locks and read-write locks in the sync package to ensure the access security of shared resources. For example, when reading and writing shared variables, we can use a mutex lock to ensure that only one goroutine can access the variable at the same time.

3. Signal processing

Go language provides the os package to process signals (signal). Signals are a method of inter-process communication in UNIX/Linux systems. They are used to notify processes of the occurrence of a certain event, such as interruption, termination, etc.

package main

import (
    "fmt"
    "os"
    "os/signal"
    "syscall"
)

func main() {
    sigs := make(chan os.Signal, 1)
    signal.Notify(sigs, syscall.SIGINT, syscall.SIGTERM)

    fmt.Println("awaiting signal")
    <-sigs
    fmt.Println("exiting")
}

In the above code, we captured the SIGINT and SIGTERM signals through the signal package and bound them to the sigs channel through the Notify function. Then, we wait for the signal to arrive by reading the signal from the sigs channel. It should be noted that we use constants defined in the syscall package to represent the type of signal. For example, SIGINT represents an interrupt signal and SIGTERM represents a termination signal.

In addition, we can also customize signal types and use the os/signal package to process them in the program. For example, we can implement simple shared state synchronization mechanisms such as distributed locks through custom signals in the program.

To sum up, the file system, multi-threading and signal processing are some of the more important features in the Go language. Their combined use allows us to write efficient and robust programs. At the same time, due to the simple syntax and good concurrency design of the Go language, it is suitable for use in cloud computing, containerization and other fields, and is a programming language that is a future trend.

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