Section 5 of 12

Error Handling

Proper error handling patterns in Go

Course Progress

Section 5 of 12

42% complete

Tutorials

Error Interface

Go handles errors as values, using the error interface for proper error handling.

Code Examples

Error Basicsgo
package main

import (
    "fmt"
    "errors"
)

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

func main() {
    result, err := divide(10, 2)
    if err != nil {
        fmt.Println("Error:", err)
    } else {
        fmt.Println("Result:", result)
    }
}
Custom Errorsgo
package main

import (
    "fmt"
)

type ValidationError struct {
    Field   string
    Message string
}

func (e ValidationError) Error() string {
    return fmt.Sprintf("validation error on %s: %s", e.Field, e.Message)
}

func validateEmail(email string) error {
    if email == "" {
        return ValidationError{
            Field:   "email",
            Message: "email cannot be empty",
        }
    }
    return nil
}

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

Exercises

Safe File Reader

Create a function that safely reads a file with proper error handling

INTERMEDIATE

Starter Code:

package main

import (
    "fmt"
    "os"
)

func readFile(filename string) (string, error) {
    // TODO: Implement safe file reading
    return "", nil
}

func main() {
    // TODO: Test with a file that exists and one that doesn't
}

Hands-on Project

Configuration File Parser

Parse and validate a configuration file with comprehensive error handling

ADVANCED

Learning Objectives

  • >Handle multiple error types
  • >Validate data
  • >Provide useful error messages

Project Tips

  • > Start by understanding the requirements
  • > Break the project into smaller tasks
  • > Test your code frequently as you build
  • > Add error handling throughout your code
  • > Consider edge cases and validate inputs
  • > Document your code with comments
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