Add observation for serde_bare

[MasterPtato]

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[MasterPtato]

Stack for rivet-dev/rivet

Current stack:

• [SLOP(claude-opus-4-8)] feat(pegboard-envoy): rate-limit envoy ws ingress and cap get_pages, trim unused metrics #5327 tnzyzqrl · 2026-06-24 20:57:36
• [SLOP(claude-opus-4-8)] feat(util): add rate limiter primitive and ingress throttles for actor create and gateway websocket #5326 pnyswwtm · 2026-06-24 20:57:35
• [SLOP(claude-opus-4-8)] feat(rivetkit-core): add serde duration and size metrics #5322 nqkrytvr · 2026-06-23 22:49:13
• Add observation for serde_bare #5321 oskoutmw · 2026-06-23 20:23:10 👈
• Add observation and ser/de metrics for serde calls #5320 ztnuwvts · 2026-06-23 20:23:09

Dependencies:

• [SLOP(claude-opus-4-8-medium)] fix(rivetkit-napi): reap completed tasks from event-loop JoinSet (#5315) #5314 xxqwtrzp · 2026-06-22 22:42:01
• main

Get stack: forklift get 5321
Push local edits: forklift submit
Merge when ready: forklift merge 5321

[claude]

Code Review

Summary

This PR adds observability (latency timing + size histograms) to every raw serde_bare::from_slice / serde_bare::to_vec call site by replacing them with the rivet_util::serde::bare_from_slice! and rivet_util::serde::bare_to_vec! macros, which emit SERIALIZE_SIZE / DESERIALIZE_SIZE histogram metrics and route through the existing observe! macro for duration tracking. The gasoline StateGuard::new switch from observe!(serde_json::from_str...)? to json_from_str! is consistent with the same pattern applied to bare.

Issues Found

Minor: Two doc-comment copy-paste errors in engine/packages/util/src/serde.rs

Lines 81 and 96 both now read /// Wraps rivet_util::serde::bare_to_vec! with observability. Line 81 documents bare_to_vec correctly, but line 96 documents bare_from_slice with the wrong name. The doc comment on line 96 should say bare_from_slice! instead.

Minor: serde_bare direct dependency may be droppable in pegboard-runner after adding rivet-util

engine/packages/pegboard-runner/Cargo.toml adds rivet-util but retains the existing serde_bare direct dependency. If all serde_bare uses in that crate now go through the macro wrapper, the direct dependency can be dropped to prevent future callsites accidentally bypassing the observability wrapper.

What Looks Good

• Every OwnedVersionedData impl in the protocol crates (runner-protocol, envoy-protocol, epoxy-protocol, ups-protocol, depot-protocol, data, depot) is consistently updated.
• The rivet-util-serde to rivet-util dependency swap in envoy-protocol/Cargo.toml is correct; the macros live in rivet-util::serde which re-exports from rivet-util-serde plus adds the observability macros on top.
• The compat_ack_tunnel_message change in pegboard-runner/src/ws_to_tunnel_task.rs correctly uses a type annotation for inference rather than a turbofish on the macro.
• The test fixtures in envoy-protocol/src/versioned/mod.rs are updated consistently with the production paths.
• The gasoline StateGuard change from observe!(serde_json::from_str::<T>(guard.0.get())?)? to json_from_str!(guard.0.get())? is semantically equivalent: the ? moved outside the macro but json_from_str! already wraps with observe! internally, so timing and size recording are preserved.
• No new unbounded metric labels are introduced. The location label used by SERIALIZE_SIZE / DESERIALIZE_SIZE is compile-time file/line/col, so it is bounded by the number of call sites in the binary rather than runtime data.
• No protocol schema changes — this is a pure call-site migration with no wire-format impact.