errutil

An error handling helper, providing more APIs than built-in package (errors, fmt), and compatible with go error interface

Why use errutil instead of built-in errors and fmt

• https://milkr.io/tsaikd/Go-lang-error-handling

Usage

• Import package from master branch

import "github.com/tsaikd/KDGoLib/errutil"

• Declare error factory

var ErrorOccurWithReason = errutil.NewFactory("An error occur, reason: %q")

• Return error with factory

func doSomething() (err error) {
	// do something

	// return error with factory,
	// first argument is parent error,
	// the others are used for factory
	return ErrorOccurWithReason.New(nil, "some reason here")
}

• Handle errors

func errorHandlingForOneCase() {
	if err := doSomething(); err != nil {
		if ErrorOccurWithReason.In(err) {
			// handling expected error
			return
		}

		// handling unexpected error
		return
	}
}

func errorHandlingForMultipleCases() {
	if err := doSomething(); err != nil {
		switch errutil.FactoryOf(err) {
		case ErrorOccurWithReason:
			// handling expected error
			return
		default:
			// handling unexpected error
			return
		}
	}
}

Optional usage

• Import from v1 branch

import "gopkg.in/tsaikd/KDGoLib.v1/errutil"

• Use like built-in errors package
  • bad case because all errors should be exported for catching by other package

func doSomething() (err error) {
	// do something

	// return error with factory
	return errutil.New("An error occur")
}