warning

README

warning

Package warning provides a simple way to handle errors that should not stop execution (return err), but rather continue.

go get github.com/lunemec/warning

Common Go idiom is this:

if err != nil {
    return err
}

But what if you wanted to distinguish between error that ends execution and error that should just be logged? This package provides you with just that.

if err != nil && !warning.IsWarning(err) {
	//This is executed only if err is not a warning.
	return
}

It also works well with https://github.com/pkg/errors and https://github.com/hashicorp/go-multierror.

Documentation

Overview

Package warning provides a simple way to handle errors that should not stop execution (return err), but rather continue.

Common Go idiom is this:

if err != nil {
	return err
}

But what if you wanted to distinguish between error that ends execution and error that should just be logged? This package provides you with just that.

if err != nil && warning.IsWarning(err) {
	// This is executed only if err is not a warning.
	return
}

It also works well with https://github.com/pkg/errors and https://github.com/hashicorp/go-multierror.

Example

package main

import (
	"fmt"

	"warning"

	"github.com/hashicorp/go-multierror"
)

func main() {
	myfunc := func() error {
		// Suppose more complicated function here.
		var multierr *multierror.Error
		for i := 0; i <= 10; i++ {
			// Process data but do not stop on errors, create just warnings.
			msg := fmt.Sprintf("Item %d did not complete.", i)
			multierr = multierror.Append(multierr, warning.New(msg))
		}

		return multierr.ErrorOrNil()
	}

	err := myfunc()
	if err != nil && !warning.IsWarning(err) {
		// Stop execution if error is not a warning.
		return
	}

	fmt.Println(err)

}

Output:
11 errors occurred:

* Item 0 did not complete.
* Item 1 did not complete.
* Item 2 did not complete.
* Item 3 did not complete.
* Item 4 did not complete.
* Item 5 did not complete.
* Item 6 did not complete.
* Item 7 did not complete.
* Item 8 did not complete.
* Item 9 did not complete.
* Item 10 did not complete.

Index

• func IsWarning(err error) bool
• func New(message string) error
• func Wrap(err error) error
• type Warning
  • func (w *Warning) Cause() error

Examples

• Package
• Warning.Cause
• Wrap

Functions

func IsWarning

func IsWarning(err error) bool

IsWarning returns true if given error is Warning type.

func New

func New(message string) error

New creates new Warning from a message.

func Wrap

func Wrap(err error) error

Wrap wraps any error into Warning.

Example

package main

import (
	"errors"
	"fmt"

	"warning"
)

func main() {
	err := warning.Wrap(errors.New("something happened but I don't want to stop"))
	if err != nil && warning.IsWarning(err) {
		fmt.Println("this is a warning")
	}

}

Output:
this is a warning

Types

type Warning

type Warning struct {
	// contains filtered or unexported fields
}

Warning type wraps error interface. This type is used to represent error that should not cause stopping of execution, but just be logged and continue.

func (*Warning) Cause

func (w *Warning) Cause() error

Cause returns the underlying cause of Warning.

Example

package main

import (
	"fmt"

	"warning"

	"github.com/hashicorp/go-multierror"
)

func main() {
	myfunc := func() error {
		// Suppose more complicated function here.
		var multierr *multierror.Error
		for i := 0; i <= 10; i++ {
			// Process data but do not stop on errors, create just warnings.
			err := fmt.Errorf("Item %d did not complete.", i)
			multierr = multierror.Append(multierr, err)
		}

		return warning.Wrap(multierr.ErrorOrNil())
	}

	// Access the underlying cause.
	err := myfunc()
	switch e := err.(type) {
	case warning.Warning:
		// Now you can access multierror's WrappedErrors()
		fmt.Printf("%T", e.Cause())
	}

}

Output:
*multierror.Error