Preventive measures in golang function error handling

Here are 5 precautions in GoLang function error handling: Use sentinel errors to indicate specific situations. Declare and return the same error in the function signature to simplify your code. Avoid returning nil and use explicit error values ​​instead. Use the defer statement to automatically release resources after the function returns. Log errors for debugging and troubleshooting purposes.

Precautions in GoLang function error handling

Error handling is a crucial concept in GoLang and helps Make sure your program still functions properly under unexpected circumstances. This guide will cover various precautions to help you avoid common error handling pitfalls.

1. Using Sentinel Errors

Sentinel errors are a set of special error values ​​used to represent specific situations. By using sentinel errors, you can convey specific error information in a more concise way.

import "errors"

var NilError = errors.New("nil value")

2. Reuse errors

Declaring and returning the same error in a function signature often simplifies code. This avoids creating and managing duplicate error objects.

func GetValue() (int, error) {
    // 处理错误并返回 sameError
    return 0, sameError
}

3. Don’t return nil

Although GoLang allows you to return nil to indicate no error, this is a best practice. Instead, you should use explicit error values.

func ValidateEmail(email string) error {
    if !strings.Contains(email, "@") {
         return errors.New("invalid email address")
    }
    return nil // 改为返回明确的错误
}

4. Using defer

The Defer statement allows you to defer execution of a function call until after the function returns. This is useful for automatically releasing resources when a function exits, regardless of error.

func OpenFile(fname string) (*File, error) {
    f, err := os.Open(fname)
    if err != nil {
        return nil, err
    }
    defer f.Close()
    // 操作文件
    return f, nil
}

5. Logging Errors

Logging errors is a valuable tool for debugging and troubleshooting. By logging errors and their contextual information, you can get to the root of the problem.

import "log"

func SomeFunction() error {
    // 处理错误
    log.Println(err)
    return err
}

Practical case:

Consider the following function, used to obtain user information:

func GetUser(id int) (*User, error) {
    u := &User{}
    err := db.QueryRow("SELECT * FROM users WHERE id = ?", id).Scan(u)
    if err != nil {
        return nil, err
    }
    return u, nil
}

By applying precautions, we can improve this function as follows :

import "errors"

var UserNotFoundError = errors.New("user not found")

func GetUser(id int) (*User, error) {
    u := &User{}
    err := db.QueryRow("SELECT * FROM users WHERE id = ?", id).Scan(u)
    if err == nil {
        return u, nil
    } else if err == sql.ErrNoRows {
        return nil, UserNotFoundError
    }
    return nil, err
}

By using sentinel errors and handling common errors correctly, we make the error handling of functions more robust and easy to understand.

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