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For modules that require multiple output destinations. Often times in elaborate scripts, you find that you need to report things to multiple destinations: TTY, logfile, etc. It would be handy to simply post the information once and have some controls at your disposal as to where it is distributed.
MessageStream is a role that implements the necessary Supplier/Supply/tap incantations to provide a single, flexible message sending .post() in your class that can be acted on by multiple subscribers.
Implement a receiver method, instantiate a MessageStream to a destination, then subscribe as many different receivers as necessary.
You send a message (and any options you desire) with .post(). The resulting stream will convert your string and optional named arguments into a MessageStream::Message object. post() will marshal that into JSON on the emit-side, the tap block will unmarshal it, and your receiver(s) can unpack it in your class. In other words, you .post() and it all arrives intact and easy to unpack for all of your receivers.
Your receiver method(s) can do whatever they want with the MessageStream::Message object. They can simply say/put/print/note, maybe add some color -- AND append the posted message to a file with a prepended timestamp, AND send to SYSLOG, AND create a CSV, AND talk to a websocket, AND perform a POST/PUT to a SharePoint Online list -- all from a single .post(). Each receiver is yours to craft and do whatever you choose with the arbitrary stuff that you pumped into the pipeline.
Once a message stream is instantiated, subscribe to it (run-time). If you want a particular destination to take a rest, unsubscribe from it. Repeat as desired.
See the example file.
Compose default receivers
Mark Devine [email protected]