Error handling in Golang: avoid hiding errors

Error handling in Golang: avoid hiding errors

Introduction:
Errors are one of the problems we often encounter in the programming process. Whether the error handling method is correct directly affects the reliability and stability of the program. In Golang, error handling is an important task, especially when we write programs that need to call external interfaces or handle complex logic. This article will focus on how to avoid hidden errors and make our programs more robust.

1. Definition and use of error types

In Golang, error types can be customized. When defining an error type, it generally needs to meet the requirements of the error interface, that is, the type needs to implement the Error() string method. This way we can define different error types based on actual business needs.

The following is a simple example that defines a custom error typeMyError:

type MyError struct {
    Msg string  // 错误信息
    Code int    // 错误码
}

func (e *MyError) Error() string {
    return fmt.Sprintf("Error: %s, Code: %d", e.Msg, e.Code)
}

We can use this error type in the code to represent specific errors . For example, if an error occurs when processing the return result of a function, an error of type MyError will be returned.

func doSomething() error {
    // 执行一些操作，可能会发生错误
    // 如果发生错误，返回一个 MyError
    return &MyError{
        Msg: "Something went wrong",
        Code: 500,
    }
}

When we call this function, we can use the if statement to determine whether an error occurred. If an error occurs, we can obtain specific error information through type assertions.

err := doSomething()
if err != nil {
    if myErr, ok := err.(*MyError); ok {
        fmt.Printf("Error: %s, Code: %d
", myErr.Msg, myErr.Code)
    } else {
        fmt.Println(err)
    }
}

2. Chained calls for error handling

In Golang, we can use the New()## provided by the errors package # Function to create a simple error.

err := errors.New("Something went wrong")

We can then use the

Wrap() function to wrap this error into a new error while adding additional contextual information.

err = errors.Wrap(err, "Failed to do something")

In this way, we can track the cause of the error step by step during error handling. Below is an example that demonstrates chaining calls for error handling.

func doSomething() error {
    err := doSomethingElse()
    if err != nil {
        return errors.Wrap(err, "Failed to do something")
    }
    return nil
}

func doSomethingElse() error {
    // 执行一些操作，可能会发生错误
    // 如果发生错误，返回一个简单的错误
    return errors.New("Something went wrong")
}

When we deal with chain calls, we can use the

Cause() function to get the error that originally occurred so that we can handle different error types.

err := doSomething()
if err != nil {
    rootErr := errors.Cause(err)
    if myErr, ok := rootErr.(*MyError); ok {
        fmt.Printf("Error: %s, Code: %d
", myErr.Msg, myErr.Code)
    } else {
        fmt.Println(err)
    }
}

Best Practices in Error Handling

Don’t Ignore Errors: When writing code, don’t ignore any errors that may occur. Even if you think an operation is unlikely to go wrong, you should still implement error handling in your code. This avoids hiding potential problems and ensures the robustness of the program.
• Handle errors as early as possible: During the execution of the program, errors should be handled as early as possible. Do not defer handling of errors until the end, as this may lead to more serious consequences and make it difficult to trace the cause of the error.
• Provide meaningful error information: When defining a custom error type, you should provide a meaningful description for the error message to facilitate subsequent error handling and debugging. The error message can contain information such as the specific location and cause of the error to help quickly locate and solve the problem.

Conclusion:

In Golang, error handling is an important task. By defining and using error types, and chaining calls for error handling, we can better avoid hidden errors and make the program more robust and reliable. At the same time, good error handling habits can also improve the maintainability and readability of the code, and facilitate subsequent maintenance and upgrades.

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