errors

github.com/Nigel2392/errors

A comprehensive utility package for error handling in Go. It provides a rich, structured error type that supports error codes, multiple related errors, and underlying causes, while seamlessly integrating with and extending the capabilities of both standard errors and github.com/pkg/errors.

Features

• Structured Errors: The Error struct allows you to define errors with specific GoCode constants, clear messages, and underlying reasons.
• Error Codes: Easily categorize and identify errors by their code rather than relying strictly on string matching.
• Cause Tracking: Chain errors and preserve the original cause using WithCause or Wrap.
• Related Errors: Store multiple related errors alongside the primary error.
• Drop-in Utility: Provides top-level wrapper functions for common operations like Is, As, Wrap, Unwrap, Join, and Cause by leveraging github.com/pkg/errors and standard library errors.

Installation

go get [github.com/Nigel2392/errors](https://github.com/Nigel2392/errors)

Usage

Creating Structured Errors

Create an error with a specific code and message:

package main

import (
    "fmt"
    "os"
    myerrors "github.com/Nigel2392/errors"
)

const ErrNotFound myerrors.GoCode = "NotFound"

func main() {
    err := myerrors.New(ErrNotFound, "user could not be located in the database")
    fmt.Println(err.Error()) 
    err2 = err.Wrap("wrapped")
    fmt.Println(err.Error()) 
    fmt.Println(err2.Error()) 

    f, err := os.Open(...)
    if err != nil && errors.Is(err, os.ErrNotExist) {
        err = ErrNotFound.WithCause(err)
    }
}

Adding Context and Causes

Attach underlying causes to your structured errors without losing the initial code context:

package main

import (
    "database/sql"
    myerrors "github.com/Nigel2392/errors"
)

func getUser() error {
    err := sql.ErrNoRows
  
    // Create a base error, then attach the sql error as the reason
    baseErr := myerrors.New("DB_ERROR", "failed to fetch user")
    return baseErr.WithCause(err)
}

Using Wrapper Utilities

You can use the package as a drop-in replacement for standard errors and github.com/pkg/errors:

package main

import (
    "fmt"
    myerrors "github.com/Nigel2392/errors"
)

func main() {
    err1 := myerrors.New("ERR_1", "first error")
    err2 := myerrors.New("ERR_2", "second error")
  
    // Join multiple errors
    joined := myerrors.Join(err1, err2)
  
    // Wrap an error with a stack trace
    wrapped := myerrors.Wrap(joined, "additional context")
  
    fmt.Println(wrapped)
}