chore: fix runner config creation

[MasterPtato]

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[MasterPtato]

• fix: add serverless backfill #3588
• chore: fix runner config creation #3580 👈 (View in Graphite)
• main

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[claude]

PR Review: Fix Runner Config Creation

Overview

This PR addresses a critical issue in runner config creation and deletion by adding graceful handling for missing runner pool workflows and implementing a backfill mechanism.

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✅ Strengths

1. Proper Error Handling: The addition of .graceful_not_found() prevents crashes when the runner pool workflow doesn't exist yet, which is essential for robustness.

2. Smart Backfill Logic: In upsert.rs:182-192, when a signal fails to find the workflow, it automatically creates one. This ensures the system self-heals and maintains consistency.

3. Good Logging: The debug log at delete.rs:57 provides useful information for troubleshooting without being too noisy.

4. Log Level Adjustment: Changing from debug to trace for GC logs in chunking.rs:106 is appropriate since this is routine housekeeping noise.

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🔍 Code Quality

Follows Repository Conventions: ✅

• Structured logging with tracing: namespace_id=?input.namespace_id, name=%input.name
• Lowercase log messages: "no runner pool workflow to bump"
• Proper use of Result types and error handling

Code Patterns: ✅

• Consistent with existing workflow signal patterns
• Proper use of tags for workflow dispatch
• Uses .unique() to prevent duplicate workflows

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🤔 Considerations & Questions

1. Race Condition Potential

In upsert.rs:172-192, there's a potential race condition:

let res = ctx.signal(/* ... */).graceful_not_found().send().await?;

// Backfill
if res.is_none() {
    ctx.workflow(/* ... */).unique().dispatch().await?;
}

Question: Between checking res.is_none() and dispatching the workflow, could another concurrent upsert create the workflow, potentially causing duplicate workflows? The .unique() should handle this, but worth verifying the uniqueness key includes both namespace_id and runner_name.

Recommendation: Verify in workflows/runner_pool.rs that the workflow's unique key is based on both namespace and runner name to prevent race conditions.

2. Asymmetry Between Delete and Upsert

• Delete (delete.rs:46-59): Only logs when workflow not found
• Upsert (upsert.rs:171-193): Creates workflow when not found

Question: Should delete also attempt to clean up or verify workflow state? Or is the current asymmetry intentional because deletion doesn't require an active workflow?

This seems reasonable on second thought - deletion is a terminal operation, so logging is sufficient.

3. Error vs None Semantics

graceful_not_found() returns None for not-found workflows. Consider:

• What if the signal fails for other reasons (network, permissions, etc.)?
• Does .send().await? propagate those errors correctly while only converting not-found to None?

This is likely correct, but worth confirming the error handling semantics of graceful_not_found().

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🧪 Testing Recommendations

1. Test workflow backfill: Verify that upserting a config when no pool workflow exists creates the workflow correctly
2. Test concurrent upserts: Ensure .unique() prevents duplicate workflows when multiple upserts race
3. Test delete with missing workflow: Confirm deletion succeeds gracefully when workflow doesn't exist
4. Test config transitions: Verify Normal → Serverless config changes trigger proper workflow creation

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🐛 Potential Issues

None identified - The changes appear sound and follow the repository's patterns correctly.

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📊 Security & Performance

• Security: ✅ No concerns
• Performance: ✅ Minimal impact - adds one conditional check and potential workflow dispatch
• Resource Management: ✅ The backfill pattern prevents orphaned configs without workflows

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📝 Minor Suggestions

1. Consider adding a comment explaining the backfill logic at upsert.rs:181-182:

// Backfill: If the workflow doesn't exist (e.g., after system restart or migration),
// create it to ensure the pool is managed
if res.is_none() {

2. Log consistency: Consider using the same log level (debug) for both delete and upsert cases for easier grepping:
   • delete.rs:57: tracing::debug!(...)
   • Could add similar log in upsert.rs when backfilling

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✨ Summary

Overall Assessment: ✅ Approve

This is a solid fix that adds necessary resilience to the runner config system. The backfill mechanism is a smart solution that makes the system self-healing. The code follows repository conventions and integrates well with the existing workflow patterns.

Key Improvements:

• Graceful handling of missing workflows
• Self-healing backfill mechanism
• Better observability with appropriate logging
• Reduced log noise for routine operations

Recommendation: Approve and merge after confirming the workflow uniqueness semantics handle the potential race condition correctly.

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commit: a7e1a7c