README.md

Mixed Persistence Service

This recipe demonstrates how to create a service in Lagom for Java that uses Cassandra for write-side persistence and JPA for a read-side view.

Implementation details

The key changes are in application.conf and HelloModule.

Specifcally, JdbcPersistenceModule is explicitly disabled:

play.modules.disabled += com.lightbend.lagom.javadsl.persistence.jdbc.JdbcPersistenceModule

Then, an explicit binding for the JDBC offset store is added back:

bind(SlickOffsetStore.class).to(JavadslJdbcOffsetStore.class);

Testing the recipe

You can test this recipe using 2 separate terminals.

On one terminal start the service:

sbt runAll

On a separate terminal, use curl to trigger some events in HelloService:

curl -H "Content-Type: application/json" -X POST -d '{"message": "Hi"}' http://localhost:9000/api/hello/Alice
curl -H "Content-Type: application/json" -X POST -d '{"message": "Good day"}' http://localhost:9000/api/hello/Bob
curl -H "Content-Type: application/json" -X POST -d '{"message": "Hi"}' http://localhost:9000/api/hello/Carol
curl -H "Content-Type: application/json" -X POST -d '{"message": "Howdy"}' http://localhost:9000/api/hello/David

After a few seconds, use curl to retrieve a list of all of the stored greetings:

curl http://localhost:9000/api/greetings
[{"id":"Alice","message":"Hi"},{"id":"Bob","message":"Good day"},{"id":"Carol","message":"Hi"},{"id":"David","message":"Howdy"}]

This is eventually consistent, so it might take a few tries before you see all of the results.