go-broadcaster

go-broadcaster is an example one-to-many publisher, built around channel primitives.

I would recommend studying it as a resource for patterns of concurrent code and API design.

The code for the broadcaster is generally quite simple. The one exception is its notify method. It might be valuable to play around with other implementations, to see how it changes behavior, and to reason about what cases the existing version covers.

For example, what's wrong with the most obvious implementation?

func (b *Broadcaster) notify(c chan<-string, m string) {
  c <- m
}

The tests should cover any changes you might make to this method.

The contract of Broadcaster is that all subscribers must consume all messages delivered to them. That is, there is no buffering or dropping of messages in the case of a slow consumer. That means, for example, that it would be problematic to have a client connected over a websocket subscribed to the broadcaster.

But that doesn't mean the Broadcaster is just a toy! If you look at the DeliverMostRecent function, you'll see a method of subscribing to Broadcaster in a way that deals with slow consumers, in this case, by only sending the most recent value.

There are many, many other ways to build new semantics on top of the Broadcaster. They are possible because of intentional choices in API design, most importantly that of leveraging channels.

I've not implemented a way to shut down the broadcaster, as it should be a natural extension of what's here.

Contributing

See the CONTRIBUTING document. Thank you, contributors!

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License

go-broadcaster is Copyright (c) 2015 thoughtbot, inc. It is free software, and may be redistributed under the terms specified in the LICENSE file.

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