Extension of Golang function life cycle

The life cycle of a Go function covers the process from declaration to exit, but can be extended in the following ways: init() function: executed before any other function call, used to initialize global variables and other operations. defer statement: defer function calls until execution when the function exits, used to release resources or clean up.

Go function life cycle extension

Go's function life cycle starts from function declaration and ends with function exit. However, this lifecycle can be extended using the init() function and the defer statement.

init() Function

init() Function is executed before any other function is called, even if it Not explicitly called. It is typically used to initialize global variables or perform other one-time operations.

package main

import "fmt"

var myVar string

func init() {
    myVar = "Hello, world!"
}

func main() {
    fmt.Println(myVar) // 输出: Hello, world!
}

defer Statement

defer statement defers execution of a function call until function exit, even if an error or panic. It is usually used to release resources or clean up.

package main

import "fmt"
import "os"

func main() {
    file, err := os.Open("myfile.txt")
    if err != nil {
        fmt.Println("Error opening file:", err)
        return
    }

    defer file.Close()

    // 对文件进行操作...
}

Practical case

In a complex application, the extension of the function life cycle can be used to achieve the following functions:

• Use the init() function to load configuration or connect to the database.
• Use the defer statement to release resources (such as file descriptors or locks) or cleanup (such as logging).
• Write a custom panic() handler to catch panic and perform graceful error handling.

By extending the function life cycle, you can write more robust and easier to maintain Go code.

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