package breaker

import "github.com/eapache/go-resiliency/breaker"

Package breaker implements the circuit-breaker resiliency pattern for Go.

Index ¶

• Variables
• type Breaker
• func New(errorThreshold, successThreshold int, timeout time.Duration) *Breaker
• func (b *Breaker) GetState() State
• func (b *Breaker) Go(work func() error) error
• func (b *Breaker) Run(work func() error) error
• type State

Examples ¶

• Breaker

Variables ¶

var ErrBreakerOpen = errors.New("circuit breaker is open")

ErrBreakerOpen is the error returned from Run() when the function is not executed because the breaker is currently open.

Types ¶

type Breaker ¶

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

Breaker implements the circuit-breaker resiliency pattern

{
	breaker := New(3, 1, 5*time.Second)

	for {
		result := breaker.Run(func() error {
			// communicate with some external service and
			// return an error if the communication failed
			return nil
		})

		switch result {
		case nil:
			// success!
		case ErrBreakerOpen:
			// our function wasn't run because the breaker was open
		default:
			// some other error
		}
	}
}

func New ¶

func New(errorThreshold, successThreshold int, timeout time.Duration) *Breaker

New constructs a new circuit-breaker that starts closed. From closed, the breaker opens if "errorThreshold" errors are seen without an error-free period of at least "timeout". From open, the breaker half-closes after "timeout". From half-open, the breaker closes after "successThreshold" consecutive successes, or opens on a single error.

func (*Breaker) GetState ¶

func (b *Breaker) GetState() State

GetState returns the current State of the circuit-breaker at the moment that it is called.

func (*Breaker) Go ¶

func (b *Breaker) Go(work func() error) error

Go will either return ErrBreakerOpen immediately if the circuit-breaker is already open, or it will run the given function in a separate goroutine. If the function is run, Go will return nil immediately, and will *not* return the return value of the function. It is safe to call Go concurrently on the same Breaker.

func (*Breaker) Run ¶

func (b *Breaker) Run(work func() error) error

Run will either return ErrBreakerOpen immediately if the circuit-breaker is already open, or it will run the given function and pass along its return value. It is safe to call Run concurrently on the same Breaker.

type State ¶

type State uint32

State is a type representing the possible states of a circuit breaker.

const (
	Closed State = iota
	Open
	HalfOpen
)

Source Files ¶

breaker.go