How golang functions handle errors gracefully

Handling errors in functions gracefully in Go involves the following trick: Use if err != nil to check for errors. Separate error handling logic and use defer statements. Use sentinel errors to represent known error types. Use multiple error types to handle multiple types of errors. Practical case: In file read and write operations, the robustness of the code can be improved by checking for errors and handling them appropriately.

Handle errors in Go functions gracefully

In Go, errors are represented as error type variable. Good error handling is crucial to writing robust and maintainable code. The following tips will help you handle errors in functions gracefully:

1. Use if err != nil

The most common way to check for errors The method is to use if err != nil, as shown below:

func f() error {
    if err := g(); err != nil {
        return fmt.Errorf("g: %w", err) // 使用 %w 封装原始错误
    }

    // 其余代码...
    return nil
}

2. Separate error handling logic

In order to keep the function simple, you can Separate error handling logic from business logic. The defer statement is used to handle errors before the function returns, as follows:

func f() (err error) {
    defer func() {
        if r := recover(); r != nil {
            // 捕获恐慌并将其转换为错误
            err = fmt.Errorf("panic: %v", r)
        }
    }()

    g()

    return
}

3. Using sentinel errors

The sentinel error is a special error, used to represent a specific type of error condition. This makes error checking simpler, as shown below:

func f() error {
    if err := g(); err == sentinelError {
        return nil // 忽略已知的错误
    }

    return err
}

4. Using multiple error types

When a function may produce multiple types of errors, you can use multiple Error type. errors.NewMultiError() The function allows the creation of errors containing multiple errors, as shown below:

func f() error {
    var errs []error

    if err := g(); err != nil {
        errs = append(errs, err)
    }

    if err := h(); err != nil {
        errs = append(errs, err)
    }

    if len(errs) > 0 {
        return errors.NewMultiError(errs...)
    }

    return nil
}

Practice case: reading and writing files

The following code example shows how to gracefully handle errors when reading and writing files:

package main

import (
    "fmt"
    "io/ioutil"
)

func main() {
    data, err := ioutil.ReadFile("data.txt")
    if err != nil {
        fmt.Printf("ReadFile: %v", err)
        return
    }

    err = ioutil.WriteFile("data-copy.txt", data, 0644)
    if err != nil {
        fmt.Printf("WriteFile: %v", err)
        return
    }
}

By using the above tips, you can gracefully handle errors in Go functions, thereby improving the robustness and readability of your code. Maintainability.

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