fix(pegboard): add threshold parameters to runner protocol metadata by MasterPtato · Pull Request #4247 · rivet-dev/rivet

MasterPtato · 2026-02-20T02:36:36Z

Description

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Type of change

Bug fix (non-breaking change which fixes an issue)
New feature (non-breaking change which adds functionality)
Breaking change (fix or feature that would cause existing functionality to not work as expected)
This change requires a documentation update

How Has This Been Tested?

Please describe the tests that you ran to verify your changes.

Checklist:

My code follows the style guidelines of this project
I have performed a self-review of my code
I have commented my code, particularly in hard-to-understand areas
I have made corresponding changes to the documentation
My changes generate no new warnings
I have added tests that prove my fix is effective or that my feature works
New and existing unit tests pass locally with my changes

railway-app · 2026-02-20T02:36:45Z

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MasterPtato · 2026-02-20T02:36:52Z

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fix(guard, runner): enforce http body size and ws msg size #4252
fix(pegboard): add threshold parameters to runner protocol metadata #4247 👈 (View in Graphite)
chore: get docker compose working again #4246
fix(epoxy): make quorum sizes match paper #4234
fix(gas): gracefully handle corrupt wf #4220 : 1 other dependent PR (#4235 )
chore: improve debugging for runners #4219
fix: add max prunes to pruner #4191
fix: add max param to prune signals cmd #4190
fix: reduce metrics aggregator cardinality #4183
fix: docker cache issues, dashboards #4181
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pkg-pr-new · 2026-02-20T02:39:26Z

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commit: 76e52b6

claude · 2026-02-20T02:45:12Z

test comment - please ignore

claude · 2026-02-20T02:45:51Z

simple test 2

claude · 2026-02-20T02:45:58Z

test with gt sign and lt sign

claude · 2026-02-20T02:46:18Z

PR Review: fix(pegboard): add threshold parameters to runner protocol metadata

Summary

This PR bumps the runner protocol to v6 to add two new fields to ProtocolMetadata: actor_stop_threshold (so runners can dynamically clamp their own timeouts) and serverless_drain_grace_period (making the previously hardcoded 10s drain grace period configurable). The refactoring of duplicated runner-lost timeout code and the Vec → HashMap cache improvement are good cleanups.

Bugs / Correctness

1. Mutation of shared definition.config.options in actor-driver.ts

const definition = lookupInRegistry(this.#config, actorConfig.name);
// ...
definition.config.options.onSleepTimeout = Math.min(...);
definition.config.options.onDestroyTimeout = Math.min(...);

If lookupInRegistry returns a reference to a shared/cached definition object (rather than a clone), this mutation persists across actor instances of the same type. The first actor to connect with a tight protocol metadata threshold would permanently clamp the timeout for every subsequent actor of the same type in that runner process. A defensive clone of definition.config.options (or limiting the mutation to the actor-local handler) should be used here.

2. Truthiness check on serverlessDrainGracePeriod may behave unexpectedly

if (protocolMetadata.serverlessDrainGracePeriod) {

The type is i64 | null, which is bigint | null at runtime. The value 0n is falsy in JavaScript, so a grace period of exactly 0 would silently skip the clamping. The check should be protocolMetadata.serverlessDrainGracePeriod !== null.

3. runnerLostThreshold > 0 compares BigInt with Number

In #startRunnerLostTimeout:

this.#protocolMetadata.runnerLostThreshold > 0

runnerLostThreshold is i64 (BigInt), and 0 is a Number. This comparison works in modern JS but is inconsistent; prefer > 0n to be explicit and avoid subtle issues in older runtimes.

4. u64 → i64 cast in conn.rs

serverless_drain_grace_period: is_serverless
    .then(|| pb.serverless_drain_grace_period() as i64),

A very large u64 value could silently wrap to a negative i64. The default (10,000 ms) is well within range, but a user setting an extremely large value could produce a confusing negative timeout on the client. Consider using u64::try_into::<i64>() with an appropriate clamp/error.

Code Quality

5. actor_stop_threshold: 0 in v5→v6 conversion

metadata: v6::ProtocolMetadata {
    runner_lost_threshold: init.metadata.runner_lost_threshold,
    actor_stop_threshold: 0,
    serverless_drain_grace_period: None,
},

Hardcoding 0 means a v5 runner will see actorStopThreshold = 0 and the engine driver will calculate Math.max(0 - 1000, 0) = 0, clamping onSleepTimeout and onDestroyTimeout to 0ms. This may be intentional (v5 runners do not support the new threshold), but a brief comment would help clarify why 0 is safe here (e.g., "0 disables clamping on older runners").

6. Missing V5 variant in ToServerMk2

pub enum ToServerMk2 {
    V4(v4::ToServer),
    V6(v6::ToServer),  // no V5
}

This is well-handled by the comment and the 5 | 6 => match arm, but the asymmetry with ToClientMk2 (which retains V5) may confuse readers. A short code comment explaining why V5 is collapsed into V6 here would help.

Performance

The Vec change for last_ping_cache is a straightforward O(n) -> O(1) improvement. Good catch.
The tokio::try_join and tokio::join calls in handle_init and allocate_actor_v2 are good concurrency improvements.

Minor Nits

The renamed endian-converter.ts appears unrelated to this PRs purpose; consider separating it.
The empty lambda formatting change in actor-driver.ts is a trivial style change that adds diff noise.
The removed comments on onSleepTimeout/onDestroyTimeout are now enforced in code rather than documented -- ensure the new clamping logic is covered by tests.

Test Coverage

No tests are added for:

The new configurable serverless_drain_grace_period behavior
The actorStopThreshold clamping in the engine driver
The v5->v6 protocol conversion (particularly the actor_stop_threshold: 0 fallback)

Given the crash/timeout implications of getting these thresholds wrong, at minimum a unit test for the actor-driver clamping logic would be valuable.

railway-app bot had a problem deploying to rivet-frontend / rivet-pr-4247 February 20, 2026 02:36 Failure

MasterPtato mentioned this pull request Feb 20, 2026

fix(epoxy): make quorum sizes match paper #4234

Open

11 tasks

MasterPtato mentioned this pull request Feb 20, 2026

chore: get docker compose working again #4246

Open

11 tasks

MasterPtato force-pushed the 02-19-fix_pegboard_add_threshold_parameters_to_runner_protocol_metadata branch from 3008d9c to 13b1948 Compare February 20, 2026 22:14

MasterPtato marked this pull request as ready for review February 20, 2026 22:14

MasterPtato requested a review from NathanFlurry February 20, 2026 22:14

railway-app bot had a problem deploying to rivet-frontend / rivet-pr-4247 February 20, 2026 22:15 Failure

MasterPtato force-pushed the 02-19-fix_pegboard_add_threshold_parameters_to_runner_protocol_metadata branch from 13b1948 to 76e52b6 Compare February 20, 2026 22:16

railway-app bot had a problem deploying to rivet-frontend / rivet-pr-4247 February 20, 2026 22:16 Failure

fix(pegboard): add threshold parameters to runner protocol metadata

ce7323c

MasterPtato force-pushed the 02-19-fix_pegboard_add_threshold_parameters_to_runner_protocol_metadata branch from 76e52b6 to ce7323c Compare February 21, 2026 01:40

MasterPtato force-pushed the 02-19-chore_get_docker_compose_working_again branch from 121bf70 to 3da1f9e Compare February 21, 2026 01:40

railway-app bot had a problem deploying to rivet-frontend / rivet-pr-4247 February 21, 2026 01:40 Failure

MasterPtato mentioned this pull request Feb 21, 2026

fix(guard, runner): enforce http body size and ws msg size #4252

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fix(pegboard): add threshold parameters to runner protocol metadata#4247

fix(pegboard): add threshold parameters to runner protocol metadata#4247
MasterPtato wants to merge 1 commit into02-19-chore_get_docker_compose_working_againfrom
02-19-fix_pegboard_add_threshold_parameters_to_runner_protocol_metadata

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MasterPtato commented Feb 20, 2026

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PR Review: fix(pegboard): add threshold parameters to runner protocol metadata

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