go-schedulable-dispatcher (gosd), is a library for scheduling when to dispatch a message to a channel.
The implementation provides an ease-of-use API with both an ingress (ingest) channel and egress (dispatch) channel. Messages are ingested and processed into a heap based priority queue for dispatching. At most two separate goroutines are used, one for processing of messages from both the ingest channel and heap then the other as a timer. Order is not guaranteed by default when messages have the same scheduled time, but can be changed through the config. By guaranteeing order, performance will be slightly worse. If strict-ordering isn't critical to your application, it's recommended to keep the default setting.
// create instance of dispatcher
dispatcher, err := gosd.NewDispatcher(&gosd.DispatcherConfig{
IngressChannelSize: 100,
DispatchChannelSize: 100,
MaxMessages: 100,
GuaranteeOrder: false,
})
checkErr(err)
// spawn process
go dispatcher.Start()
// schedule a message
dispatcher.IngressChannel() <- &gosd.ScheduledMessage{
At: time.Now().Add(1 * time.Second),
Message: "Hello World in 1 second!",
}
// wait for the message
msg := <-dispatcher.DispatchChannel()
// type assert
msgStr := msg.(string)
fmt.Println(msgStr)
// Hello World in 1 second!
// shutdown without deadline
dispatcher.Shutdown(context.Background(), false)More examples under examples.
Tested with Intel Core i7-8700K CPU @ 3.70GHz, DDR4 RAM and 1000 messages per iteration.
Benchmark_integration_unordered-12 142 8654906 ns/op
Benchmark_integration_unorderedSmallBuffer-12 147 9503403 ns/op
Benchmark_integration_unorderedSmallHeap-12 122 8860732 ns/op
Benchmark_integration_ordered-12 96 13354174 ns/op
Benchmark_integration_orderedSmallBuffer-12 121 10115702 ns/op
Benchmark_integration_orderedSmallHeap-12 129 10441857 ns/op
Benchmark_integration_orderedSameTime-12 99 12575961 ns/op