feat(cluster-operator) adding new JsonTemplateLayout support for logging

[rlanhellas]

Type of change

Enhancement

Description

Closes #11415

This PR adds support for use the JsonTemplateLayout when configuring log appenders in Log4j2.

Here is a configmap example using this new layout:

kind: ConfigMap
apiVersion: v1
metadata:
  name: strimzi-cluster-operator
  labels:
    app: strimzi
data:
  log4j2.properties: >
    name = COConfig
    monitorInterval = 30

    appender.console.type = Console

    appender.console.name = STDOUT

    appender.console.layout.type = JsonTemplateLayout

    appender.console.layout.eventTemplateUri = file:///opt/strimzi/custom-config/mylayout.json


    rootLogger.level = ${env:STRIMZI_LOG_LEVEL:-INFO}
    
    rootLogger.appenderRefs = stdout

    rootLogger.appenderRef.console.ref = STDOUT


    # Kafka AdminClient logging is a bit noisy at INFO level

    logger.kafka.name = org.apache.kafka

    logger.kafka.level = WARN


    # Keeps separate level for Netty logging -> to not be changed by the root
    logger

    logger.netty.name = io.netty

    logger.netty.level = INFO

  mylayout.json: >
    {
      "instant": {
        "$resolver": "timestamp",
        "pattern": {
          "format": "yyyy-MM-dd'T'HH:mm:ss.SSS'Z'",
          "timeZone": "UTC"
        }
      },
      "someConstant": 1,
      "message": {
        "$resolver": "message",
        "stringified": true
      }
    }

And how the message are printed on console:

{"instant":"2025-06-15T14:51:55.223Z","someConstant":1,"message":"Thread vert.x-eventloop-thread-1 has been blocked for 7802 ms, time limit is 2000 ms"}
{"instant":"2025-06-15T14:51:56.224Z","someConstant":1,"message":"Thread vert.x-eventloop-thread-1 has been blocked for 8804 ms, time limit is 2000 ms"}

Checklist

Please go through this checklist and make sure all applicable tasks have been done

• Write tests
• Make sure all tests pass
• Update documentation
• Check RBAC rights for Kubernetes / OpenShift roles
• Try your changes from Pod inside your Kubernetes and OpenShift cluster, not just locally
• Reference relevant issue(s) and close them after merging
• Update CHANGELOG.md
• Supply screenshots for visual changes, such as Grafana dashboards

[ppatierno]

Looking at the PR I think we should have the change for all other components in just one PR.
Said that I think there is the need for testing this. I see we have a LoggingChangeST class where the JsonLayout is tested maybe we should make changes there as well, otherwise we are just adding stuff to Maven without any test.
@im-konge @see-quick tagging you as ST experts.

[im-konge]

Yes I agree on having some STs for this as well. We have few for the JSON logging in the LoggingChangeST as you mentioned Paolo, so we should have similar for this.

[rlanhellas]

Fair enough. Let me work on this and update this PR.

[see-quick]

Fair enough. Let me work on this and update this PR.

If you have any questions regarding the creation of STs, please don't hesitate to ask.