feat(rhai): add apollo.router.operations.rhai.duration histogram metric (copy #9072) by mergify[bot] · Pull Request #9168 · apollographql/router

mergify · 2026-04-10T12:56:27Z

Summary

Emits a new `apollo.router.operations.rhai.duration` (`f64` histogram, unit: `s`) for every Rhai script callback execution across all pipeline stages
Attributes: `rhai.stage` (e.g. `RouterRequest`, `SubgraphResponse`), `rhai.succeeded` (bool), `rhai.is_deferred` (bool — `true` only for `@defer` stream chunks)
The two commented-out `execute()` call sites in the `define request and response body access at the router service level for rhai #3642` TODO blocks are also instrumented, so deferred-chunk metrics for Router stage will activate automatically when that issue is resolved

Design notes

No separate operation count metric: `dev-docs/metrics.md` calls for an `apollo.router.operations.rhai` counter alongside the histogram, following the coprocessor pattern. This PR intentionally omits it — the histogram datapoints are directly countable per attribute combination (`rhai.stage`, `rhai.succeeded`), so a parallel counter would be redundant. Consumers can derive counts from the histogram without the cardinality overhead of a separate instrument.

`rhai.succeeded` attribute: Uses a positive boolean rather than OTel's `error.type` convention, intentionally mirroring the `coprocessor.succeeded` attribute on `apollo.router.operations.coprocessor` for symmetry.

`f64_histogram_with_unit!` vs coprocessor: The coprocessor duration metric uses the deprecated `f64_histogram!` (no unit). This PR uses `f64_histogram_with_unit!` per the guidance in `dev-docs/metrics.md`. Migrating the coprocessor metric is a separate task (would be a breaking rename in Prometheus output).

Test plan

`cargo xtask lint --fmt` — passes clean
`cargo nextest run --lib -E 'test(rhai)'` — 7 new tests:
- `test_rhai_metric_router_request` — RouterRequest stage, succeeded=true
- `test_rhai_metric_supergraph_request` — SupergraphRequest, succeeded=true
- `test_rhai_metric_subgraph_request` — SubgraphRequest, succeeded=true
- `test_rhai_metric_subgraph_response` — SubgraphResponse (map_response path), succeeded=true
- `test_rhai_metric_deferred_response` — SupergraphResponse, both is_deferred=false (first chunk) and is_deferred=true (deferred chunk)
- `test_rhai_metric_failed_callback` — SupergraphRequest, succeeded=false
- `test_rhai_metric_no_callback_no_emission` — no callback registered = no metric emitted
`cargo nextest run --lib -E 'test(coprocessor)'` — existing coprocessor tests unaffected
Manual smoke test: run router with a Rhai script that registers a `supergraph_service` callback; confirm `apollo.router.operations.rhai.duration` appears in OTLP output with correct attributes

🤖 Generated with Claude Code

This is an automatic copy of pull request #9072 done by Mergify.

@defer

Emits a new `apollo.router.operations.rhai.duration` (f64 histogram, unit: s) for every Rhai script callback execution across all pipeline stages. Attributes: - `rhai.stage`: RouterRequest, RouterResponse, SupergraphRequest, SupergraphResponse, ExecutionRequest, ExecutionResponse, SubgraphRequest, SubgraphResponse - `rhai.succeeded`: bool — false if the script threw an EvalAltResult - `rhai.is_deferred`: bool — true for @defer stream-chunk callbacks (Supergraph/Execution response stages only; Router-stage deferred path activates automatically when #3642 is resolved) A dedicated RhaiStage enum is defined in rhai/mod.rs rather than reusing PipelineStep from the coprocessor protocol, avoiding semantic coupling to coprocessor-only variants (ConnectorRequest/Response). Uses f64_histogram_with_unit! per dev-docs/metrics.md guidance (coprocessor uses the deprecated f64_histogram! — migration is a separate task). The rhai.succeeded attribute follows the coprocessor convention rather than OTel error.type, intentionally, for symmetry. No separate operation count metric is added; the histogram datapoints are directly countable per attribute combination. Also documents the new metric in standard-instruments.mdx. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com> (cherry picked from commit 12ed389)

apollo-cla · 2026-04-10T12:56:32Z

@mergify[bot]: Thank you for submitting a pull request! Before we can merge it, you'll need to sign the Apollo Contributor License Agreement here: https://contribute.apollographql.com/

apollo-librarian · 2026-04-10T12:56:37Z

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* graphos/routing/(latest)/observability/router-telemetry-otel/enabling-telemetry/standard-instruments.mdx

Build ID: 508dc7cde8f9cfa6a8cab4fb
Build Logs: View logs

URL: https://www.apollographql.com/docs/deploy-preview/508dc7cde8f9cfa6a8cab4fb

⚠️ AI Style Review — 3 Issues Found

Summary

This pull request updates the documentation to align with style guide standards across four key sections. In text-formatting, code font is now applied to types such as Boolean, String, and other specific code symbols. The products-and-features section was updated to remove the article 'a' before standalone references to 'Rhai'. Structural-elements changes ensure that lists are introduced with a sentence or fragment ending in a colon. Finally, word-and-symbol-usage was adjusted to ensure String is used consistently when defining field or argument types in API references.

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This review is AI-generated. Please use common sense when accepting these suggestions, as they may not always be accurate or appropriate for your specific context.

So we don't have to do it at every callsite. Also, I removed the `rhai.is_deferred` property from the request side, where it's always `false` and doesn't really make sense. There is no such thing as deferred data on the request side.

goto-bus-stop

I might follow up with some cleanup of the macros here. They don't look necessary and they're confusing to a girl like me

carodewig · 2026-04-14T19:01:17Z


+/// Pipeline stage at which a Rhai script callback was invoked.
+#[derive(Clone, Copy, Debug, Display)]
+enum RhaiStage {


This should be replaced with just using PipelineStep (from services/external.rs)

hmm, maybe. I consider services/external to really be part of the coprocessor plugin (even though it lives in src/services).

I could move PipelineStep elsewhere, like in services/mod.rs, and use it in both places..?

Co-authored-by: Caroline Rodewig <16093297+carodewig@users.noreply.github.com>

mergify bot requested a review from a team as a code owner April 10, 2026 12:56

mergify bot mentioned this pull request Apr 10, 2026

feat: add apollo.router.operations.rhai.duration histogram metric #9072

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goto-bus-stop added 2 commits April 10, 2026 15:21

Record Rhai runtime inside execute()

96213db

So we don't have to do it at every callsite. Also, I removed the `rhai.is_deferred` property from the request side, where it's always `false` and doesn't really make sense. There is no such thing as deferred data on the request side.

doc alignment tweaks

504c463

goto-bus-stop approved these changes Apr 10, 2026

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carodewig reviewed Apr 10, 2026

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goto-bus-stop added 3 commits April 10, 2026 16:41

Fix chunk type in commented-out request code

c64cc5a

Remove the rhai.is_deferred attribute

ca2178f

Merge branch 'dev' into mergify/copy/dev/pr-9072

f15f5eb

abernix requested a review from a team April 14, 2026 04:46

carodewig reviewed Apr 14, 2026

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Clarify changeset

0d1e096

Co-authored-by: Caroline Rodewig <16093297+carodewig@users.noreply.github.com>

goto-bus-stop changed the title ~~feat: add apollo.router.operations.rhai.duration histogram metric (copy #9072)~~ feat(rhai): add apollo.router.operations.rhai.duration histogram metric (copy #9072) Apr 15, 2026

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feat(rhai): add apollo.router.operations.rhai.duration histogram metric (copy #9072)#9168

feat(rhai): add apollo.router.operations.rhai.duration histogram metric (copy #9072)#9168
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