JC Beasley
0bd719ab91
- Create patterns/ directory with README, manifest, and 10 initial patterns covering Ollama JSON fallback, API escaping, deprecation, PTY auth, queue-poll, LLM-as-parser, credential rotation, reverse proxy binding, human approval gates, and transient retry. - Wire pattern loading into architecture/pipeline.js based on task tags. - Update architecture/orchestrator.js to load patterns and surface them in the system prompt. - Update MEMORY.md, ARCHITECTURE.md, and CONTEXT.md to document the registry and record the decision.
33 lines
1.4 KiB
Markdown
33 lines
1.4 KiB
Markdown
# Pattern: Queue-Poll Async Job Pattern
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## Symptom
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An operation takes longer than a synchronous HTTP timeout allows (video generation, large LLM generation, batch job). The caller either times out, retries redundantly, or loses track of the job state.
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## Affected Projects
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- AI video generation pipeline (ComfyUI + WAN 2.1)
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- Long-running Ollama generations in n8n
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- Any workflow that submits work to a queue and must wait for completion
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## Root Cause
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The work is genuinely asynchronous, but the integration is designed as if it were synchronous. Without explicit job-state tracking, the system cannot wait, retry, or recover correctly.
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## Standard Fix
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1. Submit the job and immediately capture a job/prompt ID.
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2. Poll a status endpoint on a fixed interval with exponential backoff.
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3. Define terminal states (completed, failed, cancelled) and a max poll duration.
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4. Store intermediate state so a restart does not lose the job ID.
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5. Surface progress to the user if the operation is user-facing.
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## When to Apply
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- Any integration where the expected duration exceeds a reasonable HTTP timeout (~30-60 seconds).
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- Any service that returns a job ID or queue position instead of the final result.
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## Verification
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- Job submission returns an ID.
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- Polling correctly detects completion and failure.
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- No duplicate work is triggered by retries.
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- Progress/state survives a brief restart of the polling service.
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## Related Patterns
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- `transient-failure-retry`
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