lestrrat / go-circuit-breaker

[MOVED] See github.com/lestrrat-go/circuit-breaker

go-circuit-breaker

Circuit Breaker Pattern for Go

WARNING

This repository has been moved to github.com/lestrrat-go/circuit-breaker. This repository exists so that libraries pointing to this URL will keep functioning, but this repository will NOT be updated in the future. Please use the new import path.

SYNOPSIS

package breaker_test

import (
	"context"
	"time"

	"github.com/cenk/backoff"
	"github.com/lestrrat/go-circuit-breaker/breaker"
)

func Example() {
	// Need to initialize a clock to use for the
	// backoff AND the breaker
	c := breaker.SystemClock

	// Create a custom backoff strategy
	bo := backoff.NewExponentialBackOff()
	bo.Clock = c

	cb := breaker.New(
		breaker.WithBackOff(bo),
		breaker.WithClock(c),
		breaker.WithTimeout(10*time.Second),
		breaker.WithTripper(breaker.ThresholdTripper(10)),
	)

	err := cb.Call(breaker.CircuitFunc(func() error {
		// call that may trip the breaker
		return nil
	}))
	// err will be non-nill if either the circuit returns
	// an error, or the breaker is in an Open state
	_ = err
}

func ExampleEventEmitter() {
	// Use emitter to receive notifications of events
	// such as TrippedEvent, ReadyEvent, ResetEvent, etc.
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	cb := breaker.NewEventEmitter(breaker.New())
	s := cb.Subscribe(ctx)

	for {
		select {
		case e := <-s.C:
			// received event
			_ = e
		}
	}
}

DESCRIPTION

This is a fork of https://github.com/rubyist/circuitbreaker.

There were few issues (timing sensitive tests) and tweaks that I wanted to see (e.g. separating the event subscription from the core breaker, and ways to pass optional parameters), but they mostly required API changes, which is a very hard to thing to press for.

So there it is. Yet another circuit breaker :) .

CONTRIBUTING

PRs are welcome. If you have a new patch, please attach a test. If you are suggesting new API, or change, please attach a failing test to demonstrate what you are looking for. In short: please attach a test.