Collect orphaned preview artifacts without deleting live output
A worker writes an artifact then loses its lease before committing the pointer. Storage grows with orphaned previews, but a naive age-based cleanup can delete an output still being committed.
- Focused work estimate
- 3h 30m + prerequisites
- Priority in the scenario
- Medium
- Engineering practice
- Object lifecycle · Garbage collection · Race prevention · Recovery
Estimated field mix
- Storage systems50%
- Platform engineering30%
- Distributed systems20%
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
A fictional internal document portal creates previews through a trusted mock renderer. Large batches crowd out small teams, failed documents retry forever, and operators lack a safe replay command. This exercise never executes uploaded code or real document macros.
Setup prerequisites
- Queue semantics
- Database transactions
- Operational metrics
Preceding work
Complete these dependencies, or supply their agreed outputs before taking this ticket.
- QUEUE-101 · Expose a document job's current phase and terminal reason
- QUEUE-102 · Reject oversized document batches before accepting work
- QUEUE-103 · Commit job acceptance and dispatch intent together
- QUEUE-104 · Stop retrying unsupported document formats
- QUEUE-105 · Keep one team's bulk import from occupying every worker
- QUEUE-106 · Fence a late worker after its rendering lease expires
- QUEUE-107 · Cancel queued work without racing a completed preview
- QUEUE-109 · Replay a failed preview through an audited repair command
Acceptance criteria
- Separate temporary attempt artifacts from committed output references.
- Delete only unreferenced artifacts beyond a documented grace period with no active lease.
- Make cleanup resumable and record bounded deletion outcomes.
Implementation constraints
- Use synthetic objects; an artifact listing alone cannot prove an object is unreferenced.
Verification to include
- Collect an abandoned attempt artifact after its grace period.
- Race cleanup with a valid completion and prove committed output survives.
Deliverables
- Orphan collector, race fixture, and dry-run manifest
Rollout and recovery
Review deletion manifests in dry-run mode, then enable cleanup for the synthetic storage prefix only.
Value of the work
For the engineer: Practice asynchronous lifecycle control, fair scheduling, bounded retries, and artifact recovery with a deterministic provider.
For the team: See how an engineer accounts for accepted work and reduces operational toil without granting operators broad data access.
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.