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event-machine-skeleton

Dockerized skeleton for prooph software Event Machine

Installation

Please make sure you have installed Docker and Docker Compose.

Tutorial

https://proophsoftware.github.io/event-machine/tutorial/

Demo

We've prepared a demo branch that contains a small service called BuildingMgmt. It will show you the basics of event machine and the skeleton structure. To run the demo you have to clone the skeleton instead of composer create-project so that your local copy is still connected to the github repo.

*Note: Event Machine is very flexible in the way how you organize your code. The skeleton just gives an example of a possible structure. The default way is to use static aggregate methods as pure functions. However, it is also possible to use stateful OOP aggregates. Take a look at the tutorial for more information.

Head over to http://localhost:8080 to check if the containers are up and running. You should see a "It works" message.

Database

The skeleton uses a single Postgres database for both write and read model. The write model is event sourced and writes all events to prooph/event-store. The read model is created by projections (see src/Api/Projection) and is also stored in the Postgres DB. Read model tables have the prefix em_ds_ and end with a version number which is by default 0_1_0.

You can connect to the Postgres DB using following credentials (listed also in app.env):

Note: The DB runs insight a docker container. Use localhost as host name if you want to connect from your host system!

RabbitMQ

The skeleton uses RabbitMQ as a message broker with a preconfigured exchange called ui-exchange and a corresponding queue called ui-queue. You can open the Rabbit Mgmt UI in the browser: http://localhost:8081 and login with user: prooph and password: prooph.

The skeleton also contains a demo JS client which connects to a websocket and consumes messages from the ui-queue. Open http://localhost:8080/ws.html in your browser and forward events on the queue with $eventMachine->on(Event::MY_EVENT, UiExchange::class). Check src/Api/Listener for an example.

Unit and Integration Tests

We've prepared a BaseTestCase located in tests. Extend your test cases from that class to get access to some very useful test helpers. Check the tutorial for a detailed explanation.

You can run the tests using docker:

Troubleshooting

With the command docker-compose ps you can list the running containers. This should look like the following list:

Make sure that all required ports are available on your machine. If not you can modify port mapping in the docker-compose.yml.

Have you tried turning it off and on again?

If something does not work as expected try to restart the containers first:

Projection reset

Event machine uses a single projection process (read more about prooph projections in the prooph docs). You can register your own projections in event machine which are all handled by the one background process that is started automatically with the script bin/event_machine_projection.php. Also see docker-compose.yml. The projection process runs in its own docker container which is restarted by docker in case of a failure. The projection process dies from time to time to catch up with your latest code changes.

If you recognize that your read models are not up-to-date or you need to reset the read model you can use this command:

If you still have trouble try a step by step approach:

You can also check the projection log with:

Swagger UI is not updated

When you add new commands or queries in event machine the Swagger UI will not automatically reread the schema from the backend. Simply reload the UI or press Explore button.

Batteries Included

You know the headline from Docker, right? The Event Machine skeleton follows the same principle. It ships with a default set up so that you can start without messing around with configuration and such. The default set up is likely not what you want to use in production. The skeleton can be and should be adapted.

Focus of the skeleton is to provide an easy to use development environment, hence it uses default settings of Postgres and RabbitMQ containers. Make sure to secure the containers before you deploy them anywhere! You should build and use your own docker containers in production anyway. And if you cannot or don't want to use Docker then provide the needed infrastructure the way you prefer and just point event machine to it by adjusting configuration.

Powered by prooph software

Event Machine is maintained by the prooph software team. The source code of Event Machine is open sourced along with an API documentation and a getting started demo. Prooph software offers commercial support and workshops for Event Machine as well as for the prooph components.

If you are interested in this offer or need project support please get in touch.