Error handling in Golang: How to use custom error types

Error handling in Golang: How to use custom error types

In Golang, error handling is a very important task. When writing programs, we often encounter various inevitable errors, such as file reading failure, network connection disconnection, etc. Handling these errors is key to ensuring that the program runs correctly.

Golang provides a built-in error type, which is an interface type that represents the error information returned by a function. We can use it to represent any error, but typically we want to be able to differentiate between different types of errors so we can better handle them. At this time, we can customize the error type.

Custom error types can help us provide more specific and detailed error information, making it easier for us to debug and handle errors. Below, we will introduce how to use custom error types through a simple example.

package main

import (
    "errors"
    "fmt"
)

type CustomError struct {
    ErrCode int
    ErrMsg  string
}

func (e *CustomError) Error() string {
    return fmt.Sprintf("Error Code: %d, Error Message: %s", e.ErrCode, e.ErrMsg)
}

func doSomething() error {
    return &CustomError{ErrCode: 1, ErrMsg: "Something went wrong"}
}

func main() {
    err := doSomething()
    if err != nil {
        fmt.Println(err)
    }
}

In the above code, we define a CustomError type, which contains two fields: ErrCode represents the error code, and ErrMsg represents the error message. We also implemented the Error() method for the CustomError type, which returns a string representing the specific information of the error.

Our doSomething function example returns an instance of a custom error type. In the main function, we call the doSomething function and check the returned error. If the error is not empty, print it out.

By customizing error types, we can get more detailed error information, such as specific error codes and error messages. This is very helpful for us to troubleshoot and handle errors.

In addition to the above examples, we can also define more complex and rich custom error types according to actual needs. For example, we can add more fields to save contextual information about the error, or implement other custom methods to provide more functionality.

To sum up, custom error types are an important way of error handling in Golang. It allows us to provide more specific and detailed error information, making it easier for us to debug and handle errors. By judicious use of custom error types, we can write more robust and reliable code.

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