Better Error Handling

Question

In Go applications, how can we enhance error handling by defining a custom error type, such as appError, and implementing a custom handler to catch errors and write them into the response?

Answer

Gin Error Handling

Gin encourages the use of middleware to handle error responses and separate error logic from normal flow logic. To implement centralized error handling in Gin:

1. Use Middleware:

router.Use(JSONAppErrorReporter())

2. Create an Error Middleware:

func JSONAppErrorReporter() gin.HandlerFunc {
    return func(c *gin.Context) {
        c.Next()

        detectedErrors := c.Errors.ByType(gin.ErrorTypeAny)
        if len(detectedErrors) > 0 {
            err := detectedErrors[0].Err
            processedError := getProcessedError(err)
            c.JSON(processedError.Code, processedError)
            c.Abort()
        }
    }
}

3. Attach Errors to the Context:

if err != nil {
    c.Error(err)
    return
}

This approach allows you to handle errors centrally and provide consistent error responses.

Tips

• Define your own appError struct to control error codes and messages.
• Use Next() to continue middleware processing or Abort() to stop immediately.
• Consider using third-party libraries like gin-frsh-showerrors for comprehensive error handling solutions.
• Refer to the GitHub issues and examples provided for other ideas.