Best practices for error handling in golang functions

Best practices for error handling in Go include: using the error type, always returning errors, checking for errors, using multi-value returns, using sentinel errors, and using error wrappers. Practical example: In the HTTP request handler, if ReadDataFromDatabase returns an error, return a 500 error response.

Best Practices for Error Handling in Go Functions

In Go, handling errors is crucial to building robust and reliable applications. It's important. Here are some best practices to help you handle errors efficiently:

Using the error type

Go provides a built-in error Type used to represent errors. It is an interface that any type can implement, allowing you to create custom error types.

package errors

type MyError struct {
    msg string
}

func (e MyError) Error() string {
    return e.msg
}

Return an error

Always return an error, even if the name of the function does not indicate that the function may fail. This will enable the caller to determine whether the function executed successfully.

func ReadFile(filename string) (string, error) {
    data, err := ioutil.ReadFile(filename)
    return data, err
}

Checking for errors

Use the if err != nil statement to check for errors. If an error occurs, take appropriate action, such as logging the error or returning the error to the caller.

func main() {
    data, err := ReadFile("data.txt")
    if err != nil {
        log.Fatal(err)
    }
}

Use multi-value returns

If you need to return multiple values ​​for an operation that may fail, you can use multi-value returns. The first value returned is the actual result, the second value returned is the error.

func Divide(a, b int) (float64, error) {
    if b == 0 {
        return 0, errors.New("division by zero")
    }
    return float64(a) / float64(b), nil
}

Using sentinel errors

Sentinel errors are predefined error values ​​used to indicate specific types of failures. This helps you easily detect and handle these types of errors.

var ErrNotFound = errors.New("not found")

Using Error Wrapping

When you need to wrap an error to provide additional context, use fmt.Errorf or errors. Wrap function. This enables you to create more descriptive and understandable error messages.

func ReadFileFromRemote(filename string) (string, error) {
    data, err := ReadFileFromCache(filename)
    if err != nil {
        return "", fmt.Errorf("failed to read from cache: %w", err)
    }
    return data, nil
}

Practical Case: Handling Errors in HTTP Requests

Here is an example showing how to use these best practices in an HTTP request handler:

package main

import (
    "fmt"
    "net/http"
)

// 处理传入的 HTTP 请求
func handler(w http.ResponseWriter, r *http.Request) {
    data, err := ReadDataFromDatabase(r)
    if err != nil {
        // 返回一个带有 500 错误代码的错误响应
        http.Error(w, err.Error(), http.StatusInternalServerError)
        return
    }
    // 处理成功请求并返回响应
}

By following these best practices, you can write robust and reliable Go code that handles and reports errors effectively, thereby improving application stability and user experience.

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