import "github.com/go-kit/kit/sd/lb"
Package lb implements the client-side load balancer pattern. When combined with a service discovery system of record, it enables a more decentralized architecture, removing the need for separate load balancers like HAProxy.
balancer.go doc.go random.go retry.go round_robin.go
ErrNoEndpoints is returned when no qualifying endpoints are available.
Retry wraps a service load balancer and returns an endpoint oriented load balancer for the specified service method. Requests to the endpoint will be automatically load balanced via the load balancer. Requests that return errors will be retried until they succeed, up to max times, or until the timeout is elapsed, whichever comes first.
RetryWithCallback wraps a service load balancer and returns an endpoint oriented load balancer for the specified service method. Requests to the endpoint will be automatically load balanced via the load balancer. Requests that return errors will be retried until they succeed, up to max times, until the callback returns false, or until the timeout is elapsed, whichever comes first.
Balancer yields endpoints according to some heuristic.
func NewRandom(s sd.Endpointer, seed int64) Balancer
NewRandom returns a load balancer that selects services randomly.
func NewRoundRobin(s sd.Endpointer) Balancer
NewRoundRobin returns a load balancer that returns services in sequence.
Callback is a function that is given the current attempt count and the error received from the underlying endpoint. It should return whether the Retry function should continue trying to get a working endpoint, and a custom error if desired. The error message may be nil, but a true/false is always expected. In all cases, if the replacement error is supplied, the received error will be replaced in the calling context.
type RetryError struct { RawErrors []error // all errors encountered from endpoints directly Final error // the final, terminating error }
RetryError is an error wrapper that is used by the retry mechanism. All errors returned by the retry mechanism via its endpoint will be RetryErrors.
func (e RetryError) Error() string
Package lb imports 9 packages (graph) and is imported by 41 packages. Updated 2018-08-22. Refresh now. Tools for package owners.