werr

werr is a Go library that makes web error handling simpler.

This library uses Go modules and is follows the Go 1.13 convention of error values implementing Unwrap() error to express one error wrapping another.

See godoc at https://godoc.org/github.com/d0sbit/werr

Usage

// ServeHTTP implements http.Handler and thus returns no error
func (h *SomeHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {

    // wrap your handler in a WriteError which does sensible things with errors
    werr.WriteError(w, func() error {

        err := doSomeInternalThing()
        if err != nil {
            // you can return errors as-is and WriteError will
            // send a generic 500 response and log err
            return err
        }

        err = doSomeOtherThing()
        if err != nil {
            // wrapping with Error() will record the file and line number
            return werr.Error(err)
        }

        err = doSomeOtherThing2()
        if err != nil {
            // Errorf is like fmt.Errorf but automtically includes an ID and file:line number in the log
            return werr.Errorf("doSomeOtherThing2 failed: %w", err) // error only shows in log, not response
        }

        err = someThingThatMeans400IfItFails()
        if err != nil {
            // ErrorCodef is like Errorf but allows you to set an HTTP status code
            return werr.ErrorCodef(400, "bad input: %w", err) // error only shows in log, not response
        }

        err = someReallyInternalThing()
        if err != nil {
            // ErrorShowf can be used to provide an error message that shows in the response
            return werr.ErrorShowf(err, "something internal went awry") // message is sent in response and log, err shows in log
        }

        err = someReallyInternalThing2()
        if err != nil {
            // ErrorCodeShowf is like ErrorShowf but with an http response code
            return werr.ErrorCodeShowf(504, err, "something internal went awry")
        }
        
        // TODO: write successful response

        // WriteError does nothing if passed nil
        return nil 
    }())
}