Elixir to Vert.x in Examples
Distributed Systems Development A-Z Guide.
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Vert.x
Vert.x is an open source, reactive and polyglot software development toolkit from the developers of Eclipse. Reactive programming is a programming paradigm, associated with asynchronous streams, which respond to any changes or events. Similarly, Vert.x uses an event bus, to communicate with different parts of the application and passes events, asynchronously to handlers when they available. We call it polyglot due to its support for multiple JVM and non-JVM languages like Java, Groovy, Ruby, Python, and JavaScript.
Elixir
Elixir is a dynamic, functional language designed for building scalable and maintainable applications. Elixir leverages the Erlang VM, known for running low-latency, distributed and fault-tolerant systems, while also being successfully used in web development and the embedded software domain.
Make love, not war
Elixir to Vert.x event bus TCP bridge
Vert.x provides an easy-to-use TCP connection directly into event bus. It’s pretty straightforward, just take an example from here. It’s in Java.
If you don’t have a clue how to run a Vert.x service, check out our previous articles
So, how do we make Elixir talk to event bus? Using Hex package!
You can find the source code in our repo
OTP example
Let’s look at the example on event bus subscription from Elixir app. We defined a plain old GenServer(POGS) module. How will you supervise the server? It’s up to you.
To start the TCP connection and to register the subscriber, you should do
Here we’re starting the server with ExVertx.start_server. This function starts DynamicSupervisor in your supervision tree. The first argument is the from reference for the gen_statem. Yes, we have gen_statem under the hood. It requires a tuple of pid and reference as an identifier. Event address — is the event address inside the event bus. Event host and event port is a host and a port of the event bus TCP bridge.
Next, we registering events listener on event_address and that’s pretty enough to start listening to the events channel.
Let’s write a straightforward example. We can receive new events in handle_info gen_server’s callback. In the current code, we’re going to receive 3 messages from the event bus and then we unregistering from the event bus.
That’s pretty it. Thank you for reading and happy coding!
Example of the project and the source code of the entire guideline you can find in our Github repo.
