This is Pub/Sub for the Watermill project targeting NATS - primarily streaming use cases via JetStream.
It contains two packages, /pkg/nats being the current primary implementation. This supports JetStream
(default) and also some messaging use cases with core NATS but those aren't a perfect fit for watermill due
to fire and forget nature of the system - acks and nacks for example are implemented as no-ops in that mode.
However if you accept the limitations it does open up some interesting options, for example a system with
publishers that don't require confirmation could use the core NATS mode but send to subjects included in JetStream
subscriptions. This lies far enough outside the streaming use cases of watermill that its included in an
experimental fashion only but should work if resources are provisioned correctly. It can be nice to use watermill
as the sole interface to NATS in such a system if eg request/reply is not needed.
There is also an experimental /pkg/jetstream package that tracks with the experimental upstream
JetStream API. This is targeted for a
stable API within watermill by v2.1 of this package. Right now it only supports a very minimal configuration
subset but does make an effort to preserve lower level access to the underlying stream provisioning API. You can
see an example here.
All Pub/Sub implementations can be found at https://watermill.io/pubsubs/.
Watermill is a Go library for working efficiently with message streams. It is intended for building event driven applications, enabling event sourcing, RPC over messages, sagas and basically whatever else comes to your mind. You can use conventional pub/sub implementations like Kafka or RabbitMQ, but also HTTP or MySQL binlog if that fits your use case.
Documentation: https://watermill.io/
Getting started guide: https://watermill.io/docs/getting-started/
Issues: https://github.com/ThreeDotsLabs/watermill/issues
All contributions are very much welcome. If you'd like to help with Watermill development, please see open issues and submit your pull request via GitHub.
If you didn't find the answer to your question in the documentation, feel free to ask us directly!
Please join us on the #watermill channel on the Three Dots Labs Discord.
Every bit of feedback is very welcome and appreciated. Please submit it using the survey.
It processes streams!