...

As there aren't any details as to how the separation will work, specifically whether a TaskManager -> WebInterface heartbeat will exist, i will assume that there is no message that we can piggyback on.

As such the WebInterface will regularly query The WebRuntimeMonitor will contain a MetricFetcher which queries the JobManager for all available TaskManagers, and then query each of them for a metric dump. Metrics are only fetched if they actually accessed via REST calls, with a minimum time period (10 seconds) between updates.

This will be done in with a separate Thread TimerTask inside the WebRuntimeMonitorMetricFetcher, which also has the responsibility to merge the returned dumps.

The merged dump is kept in a central location inside the WebRuntimeMonitorMetricFetcher, available to different handlers.

...

MetricStore {
	void addMetric(String name, Object value);

	JobManagerMetricStore  jobManager;jobMan

	class JobManagerMetricStore {
		Map<String, Object> metrics;
	}

	Map<String, TaskManagerMetricStore> taskmanagers;

	class TaskManagerMetricStore {
		Map<String, Object> metrics;
	}

	Map<String, JobMetricStore> jobs;

	class JobMetricStore {
		Map<String, Object> metrics;
		Map<String, TaskMetricStore > tasks;
	}

	class TaskMetricStore {
		Map<String, Object> metrics;
		Map<String, SubtaskMetricStore>;
	}

	class SubtaskMetricStore  {
		Map<String, Object> metrics;
	}
}

...

Everything can be tested with unit tests.

Rejected Alternatives

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