Stamp capture time explicitly (four-slot timestamp model) - #7
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serverTs is the CAPTURE time (edgecommons/edgecommons#79): for a direct-client Modbus adapter, receive IS capture, so it must be stamped at register-read completion, not left to the data() facade's serverTs=now-at-publish default, which drifts under batchMs batching. - poll_manager: the block-read-failure path now captures the failure timestamp when the exception is caught and passes it through as server_ts (it previously fell back to publish-time stamping in the publisher's value-less path). Successful reads and decode failures already stamped read_ts at read completion. - command_service: sb/read captures serverTs explicitly at read completion (same stamp as the poll path) instead of inline at reply assembly. - publisher: docstring states the capture-time contract for every poll-path sample; the facade's at-publish default remains only as a last-resort fallback. - tests: a delayed batched flush (simulated batching latency) must carry the read-time serverTs, not the publish time, for both valued and value-less samples; the block-read-failure test now pins the capture stamp. - docs: reference/messaging-interface.md states the four-slot model (serverTs = capture time; sourceTs absent; receivedTs not emitted). 131 tests pass, coverage 95.68% (gate 90%). Co-Authored-By: Claude Fable 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_014iQDskU2E1HLStYHoZrSTn
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Implements the SOUTHBOUND four-slot timestamp model (edgecommons/edgecommons#79) for the Modbus adapter:
serverTsis the capture time — the moment the protocol read the value. For this direct-client adapter, receive IS capture, so the stamp is taken at register-read completion and passed explicitly through to each sample, never left to thedata()facade'sserverTs=now-at-publishdefault (which drifts underbatchMsbatching).sourceTsstays absent (Modbus supplies no device time);receivedTsis not emitted (degenerate for a direct client).What was drifting
poll_manager._poll_group): BAD samples for a failed block read carried noserver_ts, so the publisher's value-less path stamped them at publish/flush time — drifting by up to the wholebatchMswindow. Now the failure timestamp is captured when the exception is caught and passed through.read_tsat read completion;sb/readreplies stamped inline at reply assembly — now captured explicitly at read completion with the same stamp as the poll path.Changes
modbus_adapter/poll_manager.py— capture the failure timestamp on the block-read-failure path and pass it asserver_ts.modbus_adapter/command_service.py—sb/readcapturesserverTsat read completion.modbus_adapter/publisher.py— module docstring states the capture-time contract.tests/test_publish_events.py— new test: a delayed batched flush (simulated batching latency) carries the read-timeserverTs, not the publish time, for valued and value-less samples; block-read-failure test now pins the capture stamp.docs/reference/messaging-interface.md— one reference paragraph stating the four-slot model in present tense.Validation
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https://claude.ai/code/session_014iQDskU2E1HLStYHoZrSTn