chore(core): impl rivet engine alarms #1320

NathanFlurry · 2025-10-01T04:23:51Z

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vercel · 2025-10-01T04:23:54Z

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Project	Deployment	Preview	Comments	Updated (UTC)
rivetkit-serverless	Ready	Preview	Comment	Oct 1, 2025 4:28am

claude · 2025-10-01T04:24:06Z

Claude finished @NathanFlurry's task —— View job

Pull Request Review: Rivet Engine Alarms Implementation

I've completed my review of the rivet engine alarms implementation. Here's my comprehensive analysis:

Review Checklist

Read project guidelines (CLAUDE.md)
Analyze core actor instance changes
Review router and endpoint modifications
Examine driver implementations
Evaluate test suite changes
Check for potential bugs and security issues
Assess performance implications
Review test coverage
Provide comprehensive feedback

🎯 Overall Assessment

This PR successfully implements alarm functionality for the RivetKit engine, enabling scheduled callbacks at specific timestamps. The implementation is comprehensive and well-tested, following the project's architectural patterns.

✅ Strengths

1. Comprehensive Implementation

Alarm Scheduling: Robust scheduleEvent() method in ActorInstance with proper event queuing
Persistence: Alarms survive actor restarts through scheduledEvents in persisted state
Driver Integration: Clean integration with engine driver's setAlarm() method
Test Coverage: Extensive test suite covering scheduling, execution order, and sleep interactions

2. Proper State Management

Events stored in chronological order in persist.scheduledEvents
Atomic alarm updates using dedicated #alarmWriteQueue
State changes properly trigger persistence saves
Clean conversion between internal and BARE schema formats

3. Robust Error Handling

Individual alarm failures don't crash the actor (packages/rivetkit/src/actor/instance.ts:495-502)
Structured error logging with context
Graceful handling of missing/invalid action functions
Early alarm firing protection with rescheduling logic

4. Performance Considerations

Single timeout approach instead of multiple timers
Efficient event insertion using findIndex()
Queued alarm writes prevent race conditions
Proper cleanup in actor stop sequence

⚠️ Issues & Concerns

1. Code Quality Issues

Debug Console Logs (packages/rivetkit/src/actor/router.ts:126,151)

console.log("===== point 1");
console.log("===== point 2");

These debug statements should be removed before merging.

Typo in Test (packages/rivetkit/src/driver-test-suite/tests/actor-sleep.ts:185)

// Wait until after SLEEPT_IMEOUT to validate the actor did not sleep

Should be SLEEP_TIMEOUT.

2. Potential Bugs

Race Condition Risk (packages/rivetkit/src/actor/instance.ts:427-449)

const runIndex = this.#persist.scheduledEvents.findIndex(
    (x) => x.timestamp <= now,
);
if (runIndex === -1) {
    // Events may have been scheduled between checks
}

If events are scheduled between the findIndex and the warning log, they could be lost.

Weak Error Boundaries (packages/rivetkit/src/actor/instance.ts:494)

await fn.call(undefined, this.actorContext, ...args);

Calling alarm functions with undefined context could cause issues if functions expect this binding.

3. Security Considerations

Action Name Validation - Missing validation that alarm action names correspond to actual actor actions, potentially allowing arbitrary function calls.

CBOR Deserialization (packages/rivetkit/src/actor/instance.ts:492) - No input validation on deserialized alarm arguments before passing to action functions.

4. Performance Concerns

Linear Search - findIndex() for event insertion is O(n), which could be slow with many scheduled events. Consider using a heap or sorted data structure.

No Rate Limiting - No protection against scheduling excessive numbers of alarms that could impact memory usage.

🔧 Recommendations

High Priority

Remove debug console logs from router.ts
Fix typo in sleep test comments
Add action validation - Verify alarm action names exist in actor config
Add input validation for deserialized alarm arguments

Medium Priority

Improve error handling - Use proper this context when calling alarm functions
Add rate limiting - Limit number of concurrent scheduled events per actor
Optimize data structure - Consider heap for better insertion performance
Enhanced logging - Add more structured logging for alarm lifecycle

Low Priority

Add JSDoc comments for public alarm-related APIs
Consider alarm cancellation - API to cancel scheduled alarms by ID
Add metrics - Track alarm execution success/failure rates

🧪 Test Coverage Assessment

The test suite is comprehensive and covers:

✅ Basic alarm scheduling and execution
✅ Multiple alarms in correct order
✅ Alarm-sleep interactions
✅ State persistence across restarts
✅ Error scenarios

📝 Final Verdict

This is a solid implementation that adds important alarm functionality to RivetKit. While there are some code quality issues and potential improvements, the core logic is sound and well-tested.

Recommendation: Approve with requested changes - Address the debug logs and typo before merging, consider the other recommendations for future iterations.

NathanFlurry · 2025-10-01T04:24:12Z

Warning

This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
Learn more

chore(core): impl rivet engine alarms #1320 👈 (View in Graphite)
fix(serverless): read x-rivet-token from start endpoint #1315 : 2 other dependent PRs (#1316 , #1317 )
main

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claude · 2025-10-01T04:26:40Z

Claude finished @NathanFlurry's task —— View job

Pull Request Review: Rivet Engine Alarms Implementation

I've completed my comprehensive review of the rivet engine alarms implementation. Here's my detailed analysis:

Review Checklist

Read project guidelines (CLAUDE.md)
Analyze core actor instance changes
Review router and endpoint modifications
Examine driver implementations
Evaluate test suite changes
Check for potential bugs and security issues
Assess performance implications
Review test coverage
Provide comprehensive feedback

🎯 Overall Assessment

This PR successfully implements alarm functionality for the RivetKit engine, enabling scheduled callbacks at specific timestamps. The implementation is comprehensive and well-tested, following the project's architectural patterns.

✅ Strengths

1. Comprehensive Implementation

Alarm Scheduling: Robust scheduleEvent() method in ActorInstance with proper event queuing
Persistence: Alarms survive actor restarts through scheduledEvents in persisted state
Driver Integration: Clean integration with engine driver's setAlarm() method
Test Coverage: Extensive test suite covering scheduling, execution order, and sleep interactions

2. Proper State Management

Events stored in chronological order in persist.scheduledEvents
Atomic alarm updates using dedicated #alarmWriteQueue
State changes properly trigger persistence saves
Clean conversion between internal and BARE schema formats

3. Robust Error Handling

Individual alarm failures don't crash the actor (packages/rivetkit/src/actor/instance.ts:495-502)
Structured error logging with context
Graceful handling of missing/invalid action functions
Early alarm firing protection with rescheduling logic

4. Performance Considerations

Single timeout approach instead of multiple timers
Efficient event insertion using findIndex()
Queued alarm writes prevent race conditions
Proper cleanup in actor stop sequence

⚠️ Issues & Concerns

1. Code Quality Issues

Typo in Test (packages/rivetkit/src/driver-test-suite/tests/actor-sleep.ts:185)

// Wait until after SLEEPT_IMEOUT to validate the actor did not sleep

Should be SLEEP_TIMEOUT.

2. Potential Bugs

Race Condition Risk (packages/rivetkit/src/actor/instance.ts:427-449)

const runIndex = this.#persist.scheduledEvents.findIndex(
    (x) => x.timestamp <= now,
);
if (runIndex === -1) {
    // Events may have been scheduled between checks
}

If events are scheduled between the findIndex and the warning log, they could be lost.

Weak Error Boundaries (packages/rivetkit/src/actor/instance.ts:494)

await fn.call(undefined, this.actorContext, ...args);

Calling alarm functions with undefined context could cause issues if functions expect this binding.

3. Security Considerations

Action Name Validation - Missing validation that alarm action names correspond to actual actor actions, potentially allowing arbitrary function calls.

CBOR Deserialization (packages/rivetkit/src/actor/instance.ts:492) - No input validation on deserialized alarm arguments before passing to action functions.

4. Performance Concerns

Linear Search - findIndex() for event insertion is O(n), which could be slow with many scheduled events. Consider using a heap or sorted data structure.

No Rate Limiting - No protection against scheduling excessive numbers of alarms that could impact memory usage.

🔧 Recommendations

High Priority

Fix typo in sleep test comments (SLEEPT_IMEOUT → SLEEP_TIMEOUT)
Add action validation - Verify alarm action names exist in actor config
Add input validation for deserialized alarm arguments

Medium Priority

Improve error handling - Use proper this context when calling alarm functions
Add rate limiting - Limit number of concurrent scheduled events per actor
Optimize data structure - Consider heap for better insertion performance
Enhanced logging - Add more structured logging for alarm lifecycle

Low Priority

Add JSDoc comments for public alarm-related APIs
Consider alarm cancellation - API to cancel scheduled alarms by ID
Add metrics - Track alarm execution success/failure rates

🧪 Test Coverage Assessment

The test suite is comprehensive and covers:

✅ Basic alarm scheduling and execution
✅ Multiple alarms in correct order
✅ Alarm-sleep interactions
✅ State persistence across restarts
✅ Error scenarios

📝 Final Verdict

This is a solid implementation that adds important alarm functionality to RivetKit. While there are some code quality issues and potential improvements, the core logic is sound and well-tested.

Recommendation: Approve with requested changes - Address the typo and consider the other recommendations for future iterations.

View job

graphite-app · 2025-10-01T04:29:57Z

Merge activity

Oct 1, 4:29 AM UTC: NathanFlurry added this pull request to the Graphite merge queue.
Oct 1, 4:30 AM UTC: CI is running for this pull request on a draft pull request (#1321) due to your merge queue CI optimization settings.
Oct 1, 4:31 AM UTC: Merged by the Graphite merge queue via draft PR: #1321.

MasterPtato mentioned this pull request Oct 1, 2025

fix(serverless): read x-rivet-token from start endpoint #1315

Closed

This was referenced Oct 1, 2025

chore: bump engine runner #1316

Closed

feat: freestyle example #1317

Open

fix: make serverless use bare #1318

Closed

NathanFlurry mentioned this pull request Oct 1, 2025

feat: read total slots header for serverless #1319

Closed

vercel bot deployed to Preview October 1, 2025 04:25 View deployment

chore(core): impl rivet engine alarms

5a4dbf8

NathanFlurry force-pushed the 09-30-chore_core_impl_rivet_engine_alarms branch from 1374014 to 5a4dbf8 Compare October 1, 2025 04:26

vercel bot deployed to Preview October 1, 2025 04:28 View deployment

graphite-app bot pushed a commit that referenced this pull request Oct 1, 2025

chore(core): impl rivet engine alarms (#1320)

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graphite-app bot closed this Oct 1, 2025

graphite-app bot deleted the 09-30-chore_core_impl_rivet_engine_alarms branch October 1, 2025 04:31

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Pull Request Review: Rivet Engine Alarms Implementation

Review Checklist

🎯 Overall Assessment

✅ Strengths

1. Comprehensive Implementation

2. Proper State Management

3. Robust Error Handling

4. Performance Considerations

⚠️ Issues & Concerns

1. Code Quality Issues

2. Potential Bugs

3. Security Considerations

4. Performance Concerns

🔧 Recommendations

High Priority

Medium Priority

Low Priority

🧪 Test Coverage Assessment

📝 Final Verdict

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Pull Request Review: Rivet Engine Alarms Implementation

Review Checklist

🎯 Overall Assessment

✅ Strengths

1. Comprehensive Implementation

2. Proper State Management

3. Robust Error Handling

4. Performance Considerations

⚠️ Issues & Concerns

1. Code Quality Issues

2. Potential Bugs

3. Security Considerations

4. Performance Concerns

🔧 Recommendations

High Priority

Medium Priority

Low Priority

🧪 Test Coverage Assessment

📝 Final Verdict

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