go-errors

Error handling for Go. It uses pkg/errors under the hood.

Installation

go get github.com/nrfta/go-errors

Usage

New error

Create a new error. It uses pkg/errors for the actual error.

err := errors.New("an error message")

Wrapping errors

The errors.Wrap function returns a new error that adds context to the original error. For example

_, err := ioutil.ReadAll(r)
if err != nil {
        return errors.Wrap(err, "read failed")
}

Custom Error Code

We implement a custom error type/code for pre-defined errors. These are useful for application code to return a correct HTTP status or GraphQL error.

You can create an error using the following:

err := errors.PermissionDenied.New("user does not have access")

or you can wrap an existing as follows:

err = errors.PermissionDenied.Wrap(err)

WithDisplayMessage

Use this function to a display message to an error. Usually, error messages are meant to be used internally only, instead of displaying them to users.

You can use errors.WithDisplayMessage to assign a display message to a given error.

err := errors.New("internal message")
err = errors.WithDisplayMessage(err, "Display message goes here!")

Retrieving display messages

You can retrieve a display message by using errors.DisplayMessage.

If no message were assigned, it would use the error code string.

err := errors.New("internal message")
err = errors.WithDisplayMessage(err, "Display message goes here!")
errors.DisplayMessage(err) // -> Display message goes here!

err := errors.New("an error")
errors.DisplayMessage(err) // -> Internal Error

err := errors.NotFound.New("an error")
errors.DisplayMessage(err) // -> Not Found

Retrieving the cause of an error

Behaves the same as pkg/errors.

Note that if you create an error using this package, it returns the underlying pkg/error error.

errors.Cause recursively retrieves the topmost error which does not implement causer which is assumed to be the original cause. For example:

switch err := errors.Cause(err).(type) {
case *MyError
  // handle specifically
default:
  // unknown error
}

License

This project is licensed under the MIT License.