Awesome
JSON Event Sourcing Fanout Service
This microservice sends messages from Kafka topics to the fanout.io service. The topics should use the serialisation of JSON Event Sourcing. The usernames from the messages are used for the channel names. They are extracted from the _jwt/sub and _subscriptions/sub fields.
Configuration
The configuration is managed by the
Lightbend Config package. By default it will try to load conf/application.conf. An alternative configuration may be loaded by adding -Dconfig.resource=myconfig.conf, where the file is also supposed to be in the conf directory. The following entries are available.
| Entry | Description |
|---|---|
| environment | The name of the environment, e.g. "tst", "prd". |
| kafka | All Kafka settings come below this entry. So for example, the setting bootstrap.servers would go to the entry kafka.bootstrap.servers. |
| kafka.num.stream.threads | The number of worker threads per instance. |
| kafka.replication.factor | When using Confluent Cloud this should be 3. |
| logLevel | The log level as defined in java.util.logging.Level. |
| logTopic | The Kafka topic where the errors will be logged in the Elastic Common Schema. |
| realmIn | The realm ID for the fanout.io service. |
| realmKey | The realm key for the fanout.io service. |
| topics | The list of Kafka topics from which messages should be propagated. |
| topologyTopic | When that Kafka topic is set topology life cycle events will be sent to it. |
Building and Running
You can build the tool with mvn clean package. This will produce a self-contained JAR-file in the target directory with the form pincette-jes-fanout-<version>-jar-with-dependencies.jar. You can launch this JAR with java -jar, without further options.
The total number of threads across all the instances should not exceed the number of partitions for the Kafka topics. Additional threads will be idle.
You can run the JVM with the option -mx128m.
Docker
Docker images can be found at https://hub.docker.com/repository/docker/jsoneventsourcing/pincette-jes-fanout. You should add a configuration layer with a Docker file that looks like this:
FROM registry.hub.docker.com/jsoneventsourcing/pincette-jes-fanout:<version>
COPY conf/tst.conf /conf/application.conf
So wherever your configuration file comes from, it should always end up at /conf/application.conf.