breaker

Documentation

Index

• Variables
• func Do(name string, req func() error) error
• func DoWithAcceptable(name string, req func() error, acceptable Acceptable) error
• func DoWithFallback(name string, req func() error, fallback func(err error) error) error
• func DoWithFallbackAcceptable(name string, req func() error, fallback func(err error) error, ...) error
• func NoBreakerFor(name string)
• type Acceptable
• type Breaker
  • func GetBreaker(name string) Breaker
  • func NewBreaker(opts ...Option) Breaker
• type Option
  • func WithName(name string) Option
• type Promise

Variables

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

ErrServiceUnavailable is returned when the Breaker state is open.

Functions

func Do

func Do(name string, req func() error) error

Do calls Breaker.Do on the Breaker with given name.

func DoWithAcceptable

func DoWithAcceptable(name string, req func() error, acceptable Acceptable) error

DoWithAcceptable calls Breaker.DoWithAcceptable on the Breaker with given name.

func DoWithFallback

func DoWithFallback(name string, req func() error, fallback func(err error) error) error

DoWithFallback calls Breaker.DoWithFallback on the Breaker with given name.

func DoWithFallbackAcceptable

func DoWithFallbackAcceptable(name string, req func() error, fallback func(err error) error,
	acceptable Acceptable) error

DoWithFallbackAcceptable calls Breaker.DoWithFallbackAcceptable on the Breaker with given name.

func NoBreakerFor

func NoBreakerFor(name string)

NoBreakerFor disables the circuit breaker for the given name.

Types

type Acceptable

type Acceptable func(err error) bool

Acceptable is the func to check if the error can be accepted.

type Breaker

type Breaker interface {
	// Name returns the name of the Breaker.
	Name() string

	// Allow checks if the request is allowed.
	// If allowed, a promise will be returned, the caller needs to call promise.Accept()
	// on success, or call promise.Reject() on failure.
	// If not allow, ErrServiceUnavailable will be returned.
	Allow() (Promise, error)

	// Do runs the given request if the Breaker accepts it.
	// Do returns an error instantly if the Breaker rejects the request.
	// If a panic occurs in the request, the Breaker handles it as an error
	// and causes the same panic again.
	Do(req func() error) error

	// DoWithAcceptable runs the given request if the Breaker accepts it.
	// DoWithAcceptable returns an error instantly if the Breaker rejects the request.
	// If a panic occurs in the request, the Breaker handles it as an error
	// and causes the same panic again.
	// acceptable checks if it's a successful call, even if the err is not nil.
	DoWithAcceptable(req func() error, acceptable Acceptable) error

	// DoWithFallback runs the given request if the Breaker accepts it.
	// DoWithFallback runs the fallback if the Breaker rejects the request.
	// If a panic occurs in the request, the Breaker handles it as an error
	// and causes the same panic again.
	DoWithFallback(req func() error, fallback func(err error) error) error

	// DoWithFallbackAcceptable runs the given request if the Breaker accepts it.
	// DoWithFallbackAcceptable runs the fallback if the Breaker rejects the request.
	// If a panic occurs in the request, the Breaker handles it as an error
	// and causes the same panic again.
	// acceptable checks if it's a successful call, even if the err is not nil.
	DoWithFallbackAcceptable(req func() error, fallback func(err error) error, acceptable Acceptable) error
}

A Breaker represents a circuit breaker.

func GetBreaker

func GetBreaker(name string) Breaker

GetBreaker returns the Breaker with the given name.

func NewBreaker

func NewBreaker(opts ...Option) Breaker

NewBreaker returns a Breaker object. opts can be used to customize the Breaker.

type Option

type Option func(breaker *circuitBreaker)

Option defines the method to customize a Breaker.

func WithName

func WithName(name string) Option

WithName returns a function to set the name of a Breaker.

type Promise

type Promise interface {
	// Accept tells the Breaker that the call is successful.
	Accept()
	// Reject tells the Breaker that the call is failed.
	Reject(reason string)
}

Promise interface defines the callbacks that returned by Breaker.Allow.