Add cpp_supervised_app_simple example for the Alive API#362
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Add cpp_supervised_app_simple example for the Alive API#362Narasimha2211 wants to merge 1 commit into
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…e#234) Adds a minimal example showcasing score::mw::lifecycle::Alive, as requested: construct Alive, report Running, then ReportAlive() in a loop until SIGTERM/SIGINT, with no deadline/checkpoint supervision (that's what distinguishes it from the existing cpp_supervised_app, which uses the HealthMonitor/DeadlineMonitor API instead). - examples/cpp_supervised_app_simple/main.cpp + BUILD: modeled closely on cpp_supervised_app's structure (signal handling, set_process_name, getopt-based CLI with -s <sleep-ms>), swapping the HealthMonitor block for score::mw::lifecycle::Alive + report_running(). Depends on the //score/launch_manager:alive_cc and :lifecycle_cc aliases (same public-alias pattern the existing examples already use, since the underlying alive/lifecycle_client targets have restricted visibility). Alive construction can throw per its documented contract, so it's wrapped in try/catch for a clean error message instead of an unhandled-exception terminate(). - Registered as a new "cpp_supervised_app_simple" component in examples/demo_verification/lifecycle_demo_test.json, added to the Running run target's depends_on. Left application_type unset (defaults to "Reporting", same as lifecycle_app) since this app only demonstrates the alive heartbeat, not deadline-checkpoint supervision -- happy to change to Reporting_And_Supervised if a maintainer prefers that classification. - Added the new binary to demo_verification/BUILD's integration_test binaries list and to test_examples.py's _DEMO_APPS. - Documented the new app in examples/README.md's app table. Found and fixed a real bug while wiring up the demo config: this app's name is a literal prefix-superstring of the existing "cpp_supervised_app", and test_examples.py's process-matching was a plain unanchored substring grep over /proc/*/cmdline. That means grep -qa 'cpp_supervised_app' would also match "cpp_supervised_app_simple"'s cmdline -- breaking _assert_not_running(target, "cpp_supervised_app") after the existing SIGKILL crash-recovery step (it would spuriously find the still-alive _simple process and report the killed app as still running). Verified this concretely by simulating /proc/*/cmdline-style files locally (NUL-separated argv, both bare-name and full-path forms) and reproducing the false match, then fixing test_examples.py's _assert_running/_assert_not_running/_send_signal to convert cmdline's NUL-separated argv into one-token-per-line and anchor the match (^binary$ or ^.*/binary$) instead of doing a raw substring search -- re-ran the same simulation against the fixed logic and confirmed it correctly distinguishes the two names, still matches full-path argv0, and doesn't self-match the invoking shell's own command line (the anchoring incidentally subsumes the original bracket-class self-match-avoidance trick, so I dropped it). Verification note: this repo requires Bazel, which isn't available in my environment, so I could not build or run the integration test. Everything above was verified by reading the actual headers (score/launch_manager/src/alive/src/alive.h, .../lifecycle_client/src/report_running.h) and BUILD files to confirm target names, include paths, and visibility, by closely mirroring the existing cpp_supervised_app example, and by empirically simulating the test_examples.py matching logic outside Bazel as described above. CI should be treated as the real verification here.
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License Check Results🚀 The license check job ran with the Bazel command: bazel run --lockfile_mode=error //:license-checkStatus: Click to expand output |
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The created documentation from the pull request is available at: docu-html |
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I think we could remove this. This is not required for the functionality. In some other sample app we had this only for some demo purpose.
NicolasFussberger
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Looks good to me @Narasimha2211. Thanks for your contribution!
I only added a minor comment.
Please ensure you have an eclipse account linked to your github account so that we can merge your contribution
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Closes #234
What
Adds
examples/cpp_supervised_app_simple, a minimal example ofscore::mw::lifecycle::Alive: constructAlive, reportRunning, then callReportAlive()in a loop untilSIGTERM/SIGINT. No deadline/checkpoint supervision — that's what distinguishes it from the existingcpp_supervised_app, which uses theHealthMonitor/DeadlineMonitorAPI instead.How
main.cpp/BUILDare modeled closely oncpp_supervised_app's structure (signal handling,set_process_name,getopt-based CLI with-s <sleep-ms>), swapping theHealthMonitorblock forscore::mw::lifecycle::Alive+report_running(). Depends on the//score/launch_manager:alive_ccand:lifecycle_ccaliases — the same public-alias pattern the existing examples already use, since the underlyingalive/lifecycle_clienttargets have restricted visibility.Alive's constructor can throw per its documented contract, so it's wrapped intry/catchfor a clean error message instead of an unhandled-exceptionterminate().cpp_supervised_app_simplecomponent inexamples/demo_verification/lifecycle_demo_test.json, added to theRunningrun target'sdepends_on. Leftapplication_typeunset (defaults to"Reporting", same aslifecycle_app) since this app only demonstrates the alive heartbeat, not deadline-checkpoint supervision — happy to switch toReporting_And_Supervisedif that's the preferred classification.demo_verification/BUILD'sintegration_testbinarieslist and totest_examples.py's_DEMO_APPS.examples/README.md's table.A bug I found and fixed along the way
Wiring this into the demo config surfaced a real, pre-existing bug:
cpp_supervised_app_simpleis a literal prefix-superstring ofcpp_supervised_app, andtest_examples.py's process matching was a plain unanchored substringgrepover/proc/*/cmdline. That meansgrep -qa 'cpp_supervised_app'would also matchcpp_supervised_app_simple's cmdline — breaking_assert_not_running(target, "cpp_supervised_app")right after the existing SIGKILL crash-recovery step (it would spuriously find the still-alive_simpleprocess and report the killed app as still running, false-negating that assertion).I verified this concretely (not just by inspection) by simulating
/proc/*/cmdline-style files locally — NUL-separated argv, both bare-name and full-path forms — and reproducing the false match. Then I fixed_assert_running/_assert_not_running/_send_signalto turn cmdline's NUL-separated argv into one-token-per-line and anchor the match (^binary$or^.*/binary$) instead of a raw substring search, and re-ran the same simulation against the fixed logic to confirm it: distinguishes the two names correctly, still matches full-pathargv[0], and doesn't self-match the invoking shell's own command line (the anchoring subsumes the original bracket-class self-match-avoidance trick, so I dropped that in favor of the anchor).Verification note
This repo requires Bazel, which isn't available in my environment, so I could not build or run the integration test end-to-end. What I did verify:
score/launch_manager/src/alive/src/alive.h,.../lifecycle_client/src/report_running.h) to confirm the API surface, include paths, and target/alias visibility.cpp_supervised_appexample.test_examples.pymatching-logic bug and fix outside Bazel, as described above.python3 -m json.toolon the modifiedlifecycle_demo_test.jsonandast.parseontest_examples.py— both syntactically valid.CI should be treated as the real verification here — happy to iterate on anything that doesn't hold up once it actually builds and runs.