README.md

Squaredance

Simple task coordination

Squaredance provides a clean interface for running groups of goroutines together, where any error should end the party.

Inspired by Context, and Tomb, squaredance embraces a single way of handling these synchronization tasks.

Simple case

c := squaredance.NewCaller()

vals := make(chan string)
// Start 5 tasks
for i := 0; i < 5; i++ {
	c.Spawn(func(sf squaredance.Follower) (err error) {
		for {
			select {
			case <-sf.StopChan():
				return
			case val := <-vals:
				fmt.Printf("%s\n", val)
			}
		}
	})

}

for _, v := range []string{"swing", "your", "partner", "round", "and", "round"} {
	vals <- v
}

c.Stop()
c.Wait()

All children of a squaredance.Caller are spawned as a single function call. If any of the functions returns an error, the stop channel is closed, and the first error is returned from the .Wait() method.

Any of these functions can use the provided squaredance.Follower interfaces to listen to the stop channel, or to spawn more goroutines in the same group.

Nested peer and return error

c := squaredance.NewCaller()

c.Spawn(func(sf squaredance.Follower) error {
	val := make(chan string)
	sf.Spawn(func(sf squaredance.Follower) error {
		// This task returns immediately
		v := <-val
		fmt.Printf("Got a thing: %s\n", v)
		return fmt.Errorf("Fell down")
	})
	val <- "Spin"
	// This task waits until stop is called
	<-sf.StopChan()
	return nil
})

c.Stop()
err := c.Wait()
fmt.Printf("%v\n", err)