Nats

1. Deploy Nats using our vendored nats helmchart.

   Clone the repo and helm install the cloned chart

   helm install my-nats {local-chart-path}

2. This vendored chart comes default JetStream user. If you want to change default username and password, update the auth section found inside the values.yaml file.

3. Create a stream called DebeziumStream for Debezium to publish messages.

   Shell into the nats-box pod comes together with nats deployment and execute the below commands. If prompted for user input, press enter to accept default option.

   nats stream add DebeziumStream -s nats://{username}:{password}@localhost:4222

   When prompted, fill as per the below configuration

   Configuration:
   
            Subjects: db.*.postgres.*.*, rtus.*.postgres.*.*
    Acknowledgements: true
           Retention: File - WorkQueue
            Replicas: 1
      Discard Policy: Old
    Duplicate Window: 2m0s
   Allows Msg Delete: true
        Allows Purge: true
      Allows Rollups: false
    Maximum Messages: unlimited
       Maximum Bytes: unlimited
         Maximum Age: 7d0h0m0s
   Maximum Message Size: unlimited
   Maximum Consumers: unlimited

info

This jetstream holds all the CDC messages sent by Debezium. Those messages are discarded automatically (provided WorkQueue Retention Policy) when consumed by transformmsg service to reduce the disk space. In the event that transformmsg is down and unable to consume messages, messages are still stored up to 7days (provided config in Maximum age) before being discarded.