Go Error Lib

Overview

This is the library that defines errors and error handlers for Go application

Add this lib to your project

• Step 1:

$ export GOPRIVATE=github.com/anhvietnguyennva/go-error

• Step 2: Add file tool/tool.go with content:

package tool

import (
	_ "github.com/anhvietnguyennva/go-error/tool"
)

• Step 3:

$ go mod tidy
$ go mod vendor

Update to latest version

$ go get -u github.com/anhvietnguyennva/go-error
$ go mod vendor

How to use

Error

These errors should be used in the internal application

RestAPIError

These errors should be used in the application interface layer (API) of your service

Transforms Error to RestAPIError

package main

import (
	"fmt"

	"github.com/anhvietnguyennva/go-error/pkg/error"
	t "github.com/anhvietnguyennva/go-error/pkg/transformer"
)

func main() {
	err := error.NewErrNotFound(nil)
	transformer := t.RestTransformerInstance()
	apiErr := transformer.ErrToRestAPIErr(err)
	fmt.Println(apiErr.Error())
}

Register new Error and new RestAPIError

• There are functions can be used to create customized errors. For Error, it's error.NewError(code string, message string, entities []string, rootCause error) and it's errors.NewRestAPIError(httpStatus int, code int, message string, entities []string, rootCause error) for RestAPIError.
• You can use these above functions to create your customized errors directly. But you should define new constructors for your custom errors, so it can be reused. For example:

package main

import (
	"net/http"

	e "github.com/anhvietnguyennva/go-error/pkg/error"
)

const (
	ErrCodeCustomized = "CUSTOMIZED"
	ErrMsgCustomized  = "Customized error"

	ClientErrCodeCustomized = 40099
	ClientErrMsgCustomized  = "Customized client error"
)

func NewErrCustomized(rootCause error, entities ...string) *e.Error {
	return e.NewError(ErrCodeCustomized, ErrMsgCustomized, entities, rootCause)
}

func NewRestAPIErrCustomized(rootCause error, entities ...string) *e.RestAPIError {
	message := e.AppendEntitiesToErrMsg(ClientErrMsgCustomized, entities)
	return e.NewRestAPIError(http.StatusBadRequest, ClientErrCodeCustomized, message, entities, rootCause)
}

• After defining your custom errors, you have to register the function used to transform your custom Error to your custom RestAPIError. For example:

package main

import (
	"net/http"

	e "github.com/anhvietnguyennva/go-error/pkg/error"
	"github.com/anhvietnguyennva/go-error/pkg/transformer"
)

const (
	ErrCodeCustomized = "CUSTOMIZED"
	ErrMsgCustomized  = "Customized error"

	ClientErrCodeCustomized = 40099
	ClientErrMsgCustomized  = "Customized client error"
)

func NewErrCustomized(rootCause error, entities ...string) *e.Error {
	return e.NewError(ErrCodeCustomized, ErrMsgCustomized, entities, rootCause)
}

func NewRestAPIErrCustomized(rootCause error, entities ...string) *e.RestAPIError {
	message := e.AppendEntitiesToErrMsg(ClientErrMsgCustomized, entities)
	return e.NewRestAPIError(http.StatusBadRequest, ClientErrCodeCustomized, message, entities, rootCause)
}

func main() {
	t := transformer.RestTransformerInstance()
	t.RegisterTransformFunc(ErrCodeCustomized, NewRestAPIErrCustomized)
}

• NOTE:
  • Each error should have a unique error code. Otherwise, it can lead to unexpected results when transforming. So You should not define your custom error code as one of the predefined error codes in "go-error".
  • The ClientErrorCode should contain information about HTTP Status. It makes the error code more meaningful

For gin framework

• This lib provides the function ValidationErrToRestAPIErr(err error) which can be used when binding and validating the request.