singleflight - ActiveState ActiveGo 1.8

Package singleflight

import ""

Overview ▾

Package singleflight provides a duplicate function call suppression mechanism.

type Group

Group represents a class of work and forms a namespace in which units of work can be executed with duplicate suppression.

type Group struct {
    // contains filtered or unexported fields

func (*Group) Do

func (g *Group) Do(key string, fn func() (interface{}, error)) (v interface{}, err error, shared bool)

Do executes and returns the results of the given function, making sure that only one execution is in-flight for a given key at a time. If a duplicate comes in, the duplicate caller waits for the original to complete and receives the same results. The return value shared indicates whether v was given to multiple callers.

func (*Group) DoChan

func (g *Group) DoChan(key string, fn func() (interface{}, error)) <-chan Result

DoChan is like Do but returns a channel that will receive the results when they are ready.

func (*Group) Forget

func (g *Group) Forget(key string)

Forget tells the singleflight to forget about a key. Future calls to Do for this key will call the function rather than waiting for an earlier call to complete.

type Result

Result holds the results of Do, so they can be passed on a channel.

type Result struct {
    Val    interface{}
    Err    error
    Shared bool