[DCJ-457] Register a ThreadPoolTaskExecutor for Stairway as a Bean

[okotsopoulos]

Addresses

Partially addresses https://broadworkbench.atlassian.net/browse/DCJ-457

PRs will need to be merged in the following order:

1. [DCJ-457] Stairway can be built with a provided ThreadPoolTaskExecutor stairway#149
2. This PR
3. A forthcoming TDR PR to update its TCL version

Summary of changes

Spring Boot services which leverage TCL to configure its Stairways will now have the backing threadpool automatically instrumented via Spring Boot Actuator and Micrometer.

No additional action is required for calling services to benefit from this change, other than updating their TCL and/or Stairway dependencies to latest.

Testing Strategy

Expanded unit tests.

Verified end-to-end behavior manually:

• Publishing Stairway and TCL to my local Maven repository
• Booting up TDR, with and without maxParallelFlights specified
• Observed that stairwayExecutor metrics were automatically flowing through TDR's Actuator endpoint
• Initiated a Stairway flight which succeeded. Executor occupancy was reflected in actuator metrics.

Example where TDR configured its maxParallelFlights to be 120, has one actively running flight, and one completed flight:

(base) okotsopo@wm111-e35 jade-data-repo % curl http://localhost:8080/actuator/prometheus | grep 'stairwayExecutor'
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100 87022  100 8executor_pool_core_threads{name="stairwayExecutor",} 120.0   0
7022    0     0  10.1M      0 --:--:-- --:--:-- --:--:-- 10.3M
executor_queue_remaining_tasks{name="stairwayExecutor",} 2.147483647E9
executor_completed_tasks_total{name="stairwayExecutor",} 1.0
executor_pool_size_threads{name="stairwayExecutor",} 2.0
executor_queued_tasks{name="stairwayExecutor",} 0.0
executor_pool_max_threads{name="stairwayExecutor",} 120.0
executor_active_threads{name="stairwayExecutor",} 1.0

[nmalfroy]

Looks good to me!

[sonarcloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud