feat(cloudflare): Propagate traceparent to RPC calls - via fetch by JPeer264 · Pull Request #19991 · getsentry/sentry-javascript

JPeer264 · 2026-03-26T14:38:55Z

relates to #19327

related to #16898 (it is not really closing it as we just add context propagation without adding spans for individual calls. It needs to be defined if we need it)

It is important to know that these RPC calls do only work with the .fetch call:

const id = env.MY_DURABLE_OBJECT.idFromName('workflow-test');
const stub = env.MY_DURABLE_OBJECT.get(id);

await stub.fetch(new Request('http://my-worker/my-do-call'));

This adds RPC fetch calls between:

Workers -> Workers (Service bindings)
Workers -> DurableObjects (via standard RPC)
Workflows -> DurableObjects (also via standard RPC)

This works by instrumenting env (via instrumentEnv), which then goes over the bindings and see if there is a DurableObject or a normal Fetcher (full list of current bindings: https://developers.cloudflare.com/workers/runtime-apis/bindings/). This got inspired by how otel-cf-workers instruments their env: https://github.com/evanderkoogh/otel-cf-workers/blob/effeb549f0a4ed1c55ea0c4f0d8e8e37e5494fb3/src/instrumentation/env.ts

With this PR I added a lot of tests to check if trace propagation works (so this PR might look like it added a lot of LoC, but it is mostly tests). So I added it for schedule and queue, but it is not possible for email and tail with wrangler dev.

Potential things to change

Trace propagagtion

I added the addTraceHeaders.ts helper, as there is currently no way to reuse the existing logic (it is baked-in into the fetch instrumentations). It would be nice once #19960 lands that we can reuse it in Cloudflare to reuse existing code. I tried to write couple of tests so we don't have duplicated headers.

Adding extra spans

So there is actually a guide by OTel to add RPC spans, but was talking with someone from the OTel maintainers and they meant that this wouldn't be necessary as we already have an http.server span from out instrumented DurableObjects (and other resources) - so it wouldn't add much of information.

Without RPC span:

With RPC span:

linear-code · 2026-03-26T14:38:59Z

JS-1715 @sentry/cloudflare: Durable Object RPC spans are not linked to Worker request traces

github-actions · 2026-03-26T14:39:25Z

Semver Impact of This PR

🟡 Minor (new features)

📋 Changelog Preview

This is how your changes will appear in the changelog.
Entries from this PR are highlighted with a left border (blockquote style).

New Features ✨

Deps

Bump OpenTelemetry dependencies by andreiborza in #20046
Bump babel-loader from 10.0.0 to 10.1.1 by dependabot in #19997
Bump handlebars from 4.7.7 to 4.7.9 by dependabot in #20008

Nuxt

Add middleware instrumentation compatibility for Nuxt 5 by s1gr1d in #19968
Support parametrized SSR routes in Nuxt 5 by s1gr1d in #19977

Other

(browser) Replace element timing spans with metrics by logaretm in #19869
(bun) Add bunRuntimeMetricsIntegration by chargome in #19979

(cloudflare) Propagate traceparent to RPC calls - via fetch by JPeer264 in #19991

(core) Support embedding APIs in google-genai by nicohrubec in #19797
(node) Add nodeRuntimeMetricsIntegration by chargome in #19923
(node-core) Add OTLP integration for node-core/light by andreiborza in #19729
(solid) Add route parametrization for Solid Router by andreiborza in #20031

Bug Fixes 🐛

Ci

Update validate-pr action to remove draft enforcement by stephanie-anderson in #20037
Update validate-pr action to remove draft enforcement by stephanie-anderson in #20035

Node

Deduplicate sentry-trace and baggage headers on outgoing requests by Lms24 in #19960
Ensure startNewTrace propagates traceId in OTel environments by logaretm in #19963

Other

(browser-tests) Pin axios to 1.13.5 to avoid compromised 1.14.1 by andreiborza in #20047
(core) Guard nullish response in supabase PostgREST handler by antonis in #20033
(e2e) Pin @opentelemetry/api to 1.9.0 in ts3.8 test app by logaretm in #19992
(nuxt) Use virtual module for Nuxt pages data (SSR route parametrization) by s1gr1d in #20020
(opentelemetry) Convert seconds timestamps in span.end() to milliseconds by logaretm in #19958
(profiling) Disable profiling in worker threads by chargome in #20040
(react-router) Disable debug ID injection in Vite plugin to prevent double injection by isaacs in #19890

Documentation 📚

(release) Update publishing-a-release.md by nicohrubec in #19982

Internal Changes 🔧

Core

Remove provider-specific AI span attributes in favor of gen_ai attributes in sentry conventions by nicohrubec in #20011
Introduce instrumented method registry for AI integrations by nicohrubec in #19981
Consolidate getOperationName into one shared utility by nicohrubec in #19971

Deps

Bump amqplib from 0.10.7 to 0.10.9 by dependabot in #20000
Bump actions/upload-artifact from 6 to 7 by dependabot in #19569
Bump srvx from 0.11.12 to 0.11.13 by dependabot in #20001
Bump @apollo/server from 5.4.0 to 5.5.0 by dependabot in #20007

Deps Dev

Remove esbuild override in astro-5-cf-workers E2E test by isaacs in #20024
Bump node-forge from 1.3.2 to 1.4.0 by dependabot in #20012
Bump yaml from 2.8.2 to 2.8.3 by dependabot in #19985

Other

(browser) Reduce browser package bundle size by HazAT in #19856
(browser-tests) Add waitForMetricRequest helper by logaretm in #20002
(deno) Expand Deno E2E test coverage by chargome in #19957
(e2e) Add e2e tests for nodeRuntimeMetricsIntegration by chargome in #19989

_{🤖 This preview updates automatically when you update the PR.}

github-actions · 2026-03-26T14:49:28Z

size-limit report 📦

Path	Size	% Change	Change
@sentry/browser	25.64 kB	-	-
@sentry/browser - with treeshaking flags	24.13 kB	-	-
@sentry/browser (incl. Tracing)	42.15 kB	-	-
@sentry/browser (incl. Tracing, Profiling)	46.76 kB	-	-
@sentry/browser (incl. Tracing, Replay)	80.94 kB	-	-
@sentry/browser (incl. Tracing, Replay) - with treeshaking flags	70.56 kB	-	-
@sentry/browser (incl. Tracing, Replay with Canvas)	85.65 kB	-	-
@sentry/browser (incl. Tracing, Replay, Feedback)	97.91 kB	-	-
@sentry/browser (incl. Feedback)	42.42 kB	-	-
@sentry/browser (incl. sendFeedback)	30.3 kB	-	-
@sentry/browser (incl. FeedbackAsync)	35.28 kB	-	-
@sentry/browser (incl. Metrics)	26.95 kB	-	-
@sentry/browser (incl. Logs)	27.1 kB	-	-
@sentry/browser (incl. Metrics & Logs)	27.77 kB	-	-
@sentry/react	27.41 kB	-	-
@sentry/react (incl. Tracing)	44.48 kB	-	-
@sentry/vue	30.08 kB	-	-
@sentry/vue (incl. Tracing)	44.05 kB	-	-
@sentry/svelte	25.66 kB	-	-
CDN Bundle	28.31 kB	-	-
CDN Bundle (incl. Tracing)	43.1 kB	-	-
CDN Bundle (incl. Logs, Metrics)	29.68 kB	-	-
CDN Bundle (incl. Tracing, Logs, Metrics)	44.16 kB	-	-
CDN Bundle (incl. Replay, Logs, Metrics)	68.48 kB	-	-
CDN Bundle (incl. Tracing, Replay)	80 kB	-	-
CDN Bundle (incl. Tracing, Replay, Logs, Metrics)	81.04 kB	-	-
CDN Bundle (incl. Tracing, Replay, Feedback)	85.54 kB	-	-
CDN Bundle (incl. Tracing, Replay, Feedback, Logs, Metrics)	86.58 kB	-	-
CDN Bundle - uncompressed	82.66 kB	-	-
CDN Bundle (incl. Tracing) - uncompressed	127.81 kB	-	-
CDN Bundle (incl. Logs, Metrics) - uncompressed	86.81 kB	-	-
CDN Bundle (incl. Tracing, Logs, Metrics) - uncompressed	131.22 kB	-	-
CDN Bundle (incl. Replay, Logs, Metrics) - uncompressed	209.79 kB	-	-
CDN Bundle (incl. Tracing, Replay) - uncompressed	244.68 kB	-	-
CDN Bundle (incl. Tracing, Replay, Logs, Metrics) - uncompressed	248.08 kB	-	-
CDN Bundle (incl. Tracing, Replay, Feedback) - uncompressed	257.59 kB	-	-
CDN Bundle (incl. Tracing, Replay, Feedback, Logs, Metrics) - uncompressed	260.98 kB	-	-
@sentry/nextjs (client)	46.89 kB	-	-
@sentry/sveltekit (client)	42.62 kB	-	-
@sentry/node-core	55.76 kB	+0.02%	+8 B 🔺
@sentry/node	172.76 kB	+0.01%	+12 B 🔺
@sentry/node - without tracing	96.02 kB	+0.01%	+6 B 🔺
@sentry/aws-serverless	112.78 kB	+0.01%	+7 B 🔺

View base workflow run

timfish

Nice!

Lms24 · 2026-03-31T11:44:29Z

It would be nice once #19960 lands that we can reuse it in Cloudflare to reuse existing code. I tried to write couple of tests so we don't have duplicated headers.

FYI, #19960 landed and I agree! Right now, our various request instrumentations combine the "logic"/"algorithm" code with platform specific code how to set headers. I think it would be good if we could strip out the algorithm part into a common helper, and only leave the platform-specific parts to the individual instrumentations. From my PoV a good improvement but something we can also tackle at a later point. Happy to leave this up to you :)

Lms24 · 2026-03-31T11:49:42Z

packages/cloudflare/src/utils/addTraceHeaders.ts

+    } else if (!existing.split(',').some(entry => entry.trim().startsWith(SENTRY_BAGGAGE_KEY_PREFIX))) {
+      headers.set('baggage', `${existing},${baggage}`);
+    }


l: can we reuse mergeBaggageHeaders here?
Update: realized this is only exported from @sentry/node-core but I think that's actually worth moving to core because it should be fairly platform-independent. WDYT?

Lms24 · 2026-03-31T11:53:29Z

packages/cloudflare/src/utils/addTraceHeaders.ts

+
+  if (!headers.has('sentry-trace')) {


m: As pointed out in #19960, we should only attach any of our headers if sentry-trace isn't set yet. So we could most likely just early return here.

Lms24 · 2026-03-31T12:00:44Z

packages/cloudflare/src/instrumentations/worker/instrumentFetcher.ts

+    const newInit = addTraceHeaders(input, init);
+
+    return fetchFn(input, newInit);


m/q: is this how we add our tracing headers in our core/browser fetch instrumentation as well? Just wanted to double check because injecting headers into fetch arguments is a bit tricky with the various forms of input and init and the precedence.

I think adding headers to init is fine. Though us deep-copying headers from input to init, and then init again might be unexpected if one of the objects is reused by users across multiple requests. Anyway, not saying something is off but that we should double check that this is how we do it in the other SDKs as well.

JPeer264 requested review from Lms24, logaretm and timfish March 26, 2026 14:38

JPeer264 self-assigned this Mar 26, 2026

JPeer264 force-pushed the jp/rpc-instrument branch from 3bd82cc to 71a3936 Compare March 26, 2026 14:54

JPeer264 mentioned this pull request Mar 26, 2026

feat(cloudflare): Support basic WorkerEntrypoint #19884

Open

timfish approved these changes Mar 26, 2026

View reviewed changes

JPeer264 changed the title ~~feat(cloudflare): Propagate traceparent to RPC calls~~ feat(cloudflare): Propagate traceparent to RPC calls - via fetch Mar 31, 2026

feat(cloudflare): Propagate traceparent to RPC calls

3097f54

JPeer264 force-pushed the jp/rpc-instrument branch from 71a3936 to 3097f54 Compare March 31, 2026 11:25

Lms24 reviewed Mar 31, 2026

View reviewed changes

		const newInit = addTraceHeaders(input, init);

		return fetchFn(input, newInit);

Uh oh!

Conversation

JPeer264 commented Mar 26, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Potential things to change

Trace propagagtion

Adding extra spans

Uh oh!

linear-code bot commented Mar 26, 2026

Uh oh!

github-actions bot commented Mar 26, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Semver Impact of This PR

New Features ✨

Deps

Nuxt

Other

Bug Fixes 🐛

Ci

Node

Other

Documentation 📚

Internal Changes 🔧

Core

Deps

Deps Dev

Other

Uh oh!

github-actions bot commented Mar 26, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

size-limit report 📦

Uh oh!

timfish left a comment

Choose a reason for hiding this comment

Uh oh!

Lms24 commented Mar 31, 2026

Uh oh!

Lms24 Mar 31, 2026

Choose a reason for hiding this comment

Uh oh!

Lms24 Mar 31, 2026

Choose a reason for hiding this comment

Uh oh!

Lms24 Mar 31, 2026

Choose a reason for hiding this comment

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

3 participants

JPeer264 commented Mar 26, 2026 •

edited

Loading

github-actions bot commented Mar 26, 2026 •

edited

Loading

github-actions bot commented Mar 26, 2026 •

edited

Loading