chore: reworked stats collector to be based on vertx route handler to be abl…

[mswiderski]

…e to catch all requests/responses

[Copilot]

🟡 Changes recommended

Shutdown can race with completion updates or remain deferred indefinitely by an unfinished request.

2 open findings

• Record completion before decrementing in-flight requests · New
• Retain retry limit to prevent workers staying alive indefinitely · New

What changed in this PR

Moves request tracking from REST filters to Vert.x routing so worker shutdown accounts for more request and response paths.

Changes:

• Tracks active requests and their latest activity, excluding probes and event streams.
• Updates delayed shutdown to use the new statistics.
• Adds lifecycle tests and test dependencies.

File	Description
service/​worker/​src/​main/​java/​ai/​timefold/​solver/​service/​worker/​impl/​ShutdownExecutor.java	Uses active-request counts and activity timestamps for shutdown.
service/​rest/​src/​test/​java/​ai/​timefold/​solver/​service/​rest/​impl/​stats/​StatisticsCollectorImplTest.java	Tests completion, failure, disconnects, and exclusions.
service/​rest/​src/​main/​java/​ai/​timefold/​solver/​service/​rest/​impl/​stats/​StatisticsCollectorImpl.java	Implements router-level request tracking.
service/​rest/​pom.xml	Adds test dependencies.
service/​definition/​src/​main/​java/​ai/​timefold/​solver/​service/​definition/​internal/​stats/​StatisticsCollector.java	Exposes request counts and activity timestamps.

🧠 Review effort: Balanced

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[Copilot]

🔵 Needs a closer look

The event-stream exclusion can leave ordinary uploads untracked and vulnerable to shutdown.

0 open findings

2 resolved since last review

• Retain retry limit to prevent workers staying alive indefinitely
• Record completion before decrementing in-flight requests

Previously missed (1)

In code that hasn't changed since last review

Restrict event route exemption to GET requests

service/​rest/​src/​main/​java/​ai/​timefold/​solver/​service/​rest/​impl/​stats/​StatisticsCollectorImpl.java:67

For a model exposed at /v1/events (allowed by TimefoldModelDescriptorProcessor#getResourceTypeFromPath), this suffix check also excludes ordinary POST uploads from activity tracking, allowing the worker to shut down during an upload when its idle delay expires; restrict the exemption to actual GET /{id}/events routes.

🧠 Review effort: Balanced

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[Copilot]

🟡 Changes recommended

A request-path edge case can still cause event streams to delay worker shutdown.

1 open finding

• Trailing-slash event stream incorrectly blocks worker shutdown · New

🧠 Review effort: Balanced

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[Copilot]

🟢 Approval recommended

No blocking defects were identified in the tracking implementation or shutdown integration.

1 open finding

• Add regression test for trailing-slash event-stream exclusion · New

1 resolved since last review

• Trailing-slash event stream incorrectly blocks worker shutdown

🧠 Review effort: Balanced

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[rsynek]

One comment - up to you if you decide to take it up, as it hasn't been introduced by this PR.