verrors

Project archived!

The package was a try to deal with errors before Go 1.13 was a thing. It doesn't make much sense now, so I'm closing the repository.

Still, looking back at it after five years, I think it was a nice try! :)

Description

Package verrors provides simple helpers for creating errors, which can be checked for their "traits".

Package exposes only 2 functions: "WithValue" and "Value", which helps creating error constructors and trait checks.

This package is created as extension of github.com/pkg/errors, but pkg/errors is not required. You can wrap errors by errors.Wrap and trait checks will still work.

Example:

import (
    "github.com/pkg/errors"
    "github.com/m-zajac/verrors"
)

// type for error keys
type errKey string

// key for "temporary" error
const temporaryErrKey errKey = "temporary"

// NewTemporaryError creates temporary error
func NewTemporaryError(e error) error {
    return verrors.WithValue(e, temporaryErrKey, true)
}

// IsTemporary checks if error has "temporary" nature
func IsTemporary(e error) bool {
    if v := verrors.Value(e, temporaryErrKey); v == nil {
	   return false
    }
    return true
}

// ...

err := NewTemporaryError(errors.New("tmp error"))

// Fake some wraps. In real code wraps would happen while moving up the call stack.
err = errors.Wrap(err, "some context 1")
err = errors.Wrap(err, "some context 2")

// ...

if IsTemporary(err) {
    println("Should retry...") // error cause is created by NewTemporaryError, so this is the case
} else {
    panic("I'll end here.")
}

Read the package documentation for more information.