errm

Package errm is wrapper on eris for convinient usage of errors with structrual fields and stack trace

Install: go get github.com/maxbolgarin/errm

Why you should try
How to use
Contributing

Why you should try

There are familiar methods like New, Errorf, Wrap and others that works as expected. But there are two breaking futures:

There is a stack trace in every error, thanks for the eris
You can add field=value pairs to make an error message more convinient to handle in future

Which option is better for further search and analysis?

err1: cannot start server 'orders' at address: :7000: port is in use
err2: cannot start server=orders address=:7000: port is in use

The second one can be easily parsed and it is more friedly to read. Here is the code for these two examples:

err1 := fmt.Errorf("cannot start server '%s' at address: %s: %w", name, addr, err)
err2 := errm.Wrap(err, "cannot start", "server", name, "address", addr)

How to use

New error

err := errm.New("some-err", "field", "value", "field2", []any{123, 321}, "field3", 123, "field4")
fmt.Println(err) 

// some-err field=value field2=[123 321] field3=123

Wrap error

notFoundErr := errm.New("not found")

name := "database"
err2 := errm.Wrapf(err1, "another error with %s", name, "address", "127.0.0.1")

if errm.Is(err2, notFoundErr) {
    fmt.Println(err2)
}

// another error with database address=127.0.0.1: not found

Error List

randomErr := errm.Errorf("some random error with %s", "unwanted behaviour")
notFoundErr := errm.New("not found")

errList := errm.NewList()
errList.Add(randomErr)
errList.New("some error", "retry", 1)
errList.Wrap(notFoundErr, "database error")

if errList.Has(notFoundErr) {
    finalErr := errList.Err()
    fmt.Println(errm.Wrap(finalErr.Error(), "multi error")) 
}

// multi error: some random error with unwanted behaviour; some error retry=1; database error: not found

Error Set

errSet := errm.NewSet()

// Add the same error for three times
notFoundErr := errm.New("not found")
errSet.Add(notFoundErr)
errSet.Add(notFoundErr)
errSet.Add(notFoundErr)
fmt.Println(errSet.Len()) // 1

// Add two errors with the same message
errSet.Add(errm.New("A"))
errSet.Add(errm.New("A"))
fmt.Println(errSet.Len()) // 2

// Add an another error but with the same message
err := errors.New("A")
errSet.Add(err)
fmt.Println(errSet.Len()) // 2

// Add wrapped -> got another error message -> another error
errSet.Add(errm.Wrap(notFoundErr, "another error"))
fmt.Println(errSet.Len()) // 3

Contributing

If you'd like to contribute to errm, make a fork and submit a pull request!

Released under the MIT License