Use monotonic time for edge-job timeout deadlines
Moving the emulator wall clock backward extends a running job forever. Measure elapsed timeout against monotonic time.
- Focused work estimate
- 1h 15m + prerequisites
- Priority in the scenario
- High
- Engineering practice
- Time · Abstraction
Estimated field mix
- Embedded and edge100%
Field percentages are editorial estimates of the ticket's engineering focus. They total 100%; they are not measured time, proficiency scores, or ownership evidence.
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Project context
Fictional kiosk software schedules cache refresh and display housekeeping. Build a software clock and job adapter; do not control real machinery or purchase hardware.
Setup prerequisites
- Implement injected wall and monotonic clocks.
- Create synthetic jobs with controllable completion and failure.
Preceding work
No earlier ticket is required. Complete the project setup above.
Acceptance criteria
- Wall-clock changes do not extend timeout
- Deadline fires once
- Elapsed duration cannot become negative
Implementation constraints
- Expose both clocks through interfaces.
Verification to include
- Move wall clock during job
- Advance monotonic clock past deadline
Deliverables
- Deadline helper and clock cases
Rollout and recovery
Disable timed jobs if monotonic source is unavailable.
Value of the work
For the engineer: Practice timer semantics, cancellation and bounded scheduling.
For the team: Inspect predictable edge resource use and honest execution status.
Evidence boundaries
Outcome Evidence: Tests, patches, and runbooks are requested deliverables. They become Outcome Evidence only through a qualified Mission and immutable Evidence IDs.
Ownership Evidence: Independent adaptation must be observed under a declared verification policy and cite immutable Evidence IDs. Completing a planning ticket establishes no Ownership Evidence.