Tracing without Performance

[stephanie-anderson]

Problem Statement

It should be possible that tracing information is propagated from/to incoming/outgoing HTTP requests even if performance is disabled and thus no transactions/spans are available.

Solution Brainstorm

Requirements:

1. All error, transaction and check-in events sent to Sentry always contain a Dynamic Sampling Context (trace) envelope header item.
2. All error, transaction and check-in events sent to Sentry always contain a trace context.
3. All outgoing HTTP requests always contain a sentry-trace and baggage header if the destination is allow-listed in [tracePropagationTargets](https://develop.sentry.dev/sdk/performance/#tracepropagationtargets).

Part 1: Standardize tracePropagationTargets

Beta Give feedback

1. feat(types): Add tracePropagationTargets to top level options #8395
   +0
   
2. feat(tracing): Favour client options tracePropagationTargets #8399
   +0
   
3. feat: Update JS docs to use top level tracePropagationTargets sentry-docs#7267
   +0
   
4. Deprecate BrowserTracing tracePropogationTargets in favour of top level option

Part 2: Setting up PropagationContext

Beta Give feedback

1. feat(tracing): Add PropagationContext to scope #8421
   +0
   
2. feat(node): Populate propagation context using env variables #8422
   +0
   
3. ref(nextjs): Set propagation context for tracing #8426
   +0
   
4. ref(remix): Extract propagation context in request handler #8427
   +0
   
5. ref(sveltekit): Extract propagation context #8428
   +0
   
6. ref(tracing): Extract propagation context from meta tags #8430
   +0
   
7. ref(serverless): Extract propagation context #8429
   +0
   
8. ref(node): Extract propagation context in tracingHandler #8425
   +0
   
9. Make sure we support sentry-trace when it is an array [WON'T DO]

Part 3: Tracing without Performance

Beta Give feedback

1. ref(tracing): Add necessary helpers for using propagation context on outgoing headers #8434
   +0
   
2. feat(node): Add tracing without performance to Node Undici #8449
   +0
   
3. feat(node): Add tracing without performance to Node http integration #8450
   +0
   
4. feat(tracing): Add tracing without performance to browser and client Sveltekit #8458
   +0
   
5. feat(node): Add trace context to checkin #8503
   +0
   
6. Add DSC trace header to all outgoing envelopes
7. [OPTIONAL] Update transaction creation to use PropagationContext [WON'T DO]
8. Inject meta tags in Tracing-without-Performance-mode #8520
   6 of 7
   Feature: Tracing Type: Improvement +2

Part 5: Final touches

Beta Give feedback

1. Run e2e test to show it works (replay, crons, errors) - head SDK + tail SDK
2. feat(js): Add js tracing without performance docs sentry-docs#7421
   +0
   
3. fix(node): Set propagation context even when tracingOptions are not defined #8517
   +0
   
4. Write down key changes needed for React Native/Electron adopting Tracing without Performance

[AbhiPrasad]

We might want to explore if it's worth it to create a separate integration for browser JS that enables distributed tracing, but not take the bundle size hit of all of performance monitoring.

[danielkhan]

We might want to explore if it's worth it to create a separate integration for browser JS that enables distributed tracing, but not take the bundle size hit of all of performance monitoring.

Each dedicated package increases complexity for us but also for our users.
Additionally, it makes it harder to transition to performance as they have to change the SDK.

If the difference isn't really game-changing significant, I would not do that right now.

[AbhiPrasad]

Each dedicated package increases complexity for us but also for our users.

This wouldn't be a dedicated package, but instead just a different integration exported from Sentry. Swapping them would be as easy as removing one integration and using another.

import * as Sentry from '@sentry/browser';

Sentry.init({
  integrations: [
    // Tracing + Performance Monitoring
    // Sentry.BrowserTracing(),
    //
    // Just Tracing (name tbd, hardest problem in computer science and all of that)
    // Sentry.PlainTracing
  ],
});

[AbhiPrasad]

Initial support released with https://github.com/getsentry/sentry-javascript/releases/tag/7.58.0

I opened #8520 to extract task for meta tags.

All thats left now is to merge in docs (getsentry/sentry-docs#7421) and to write down key learnings so that we can add twp support to react native and electron.

[AbhiPrasad]

For electron and react native:

To add tracing without performance support on top of the JS SDKs, you can do the following:

sentry-javascript/packages/node/src/integrations/http.ts

Lines 257 to 275 in 459c5d2

	if (shouldAttachTraceData(rawRequestUrl)) {
	if (requestSpan) {
	const sentryTraceHeader = requestSpan.toTraceparent();
	const dynamicSamplingContext = requestSpan?.transaction?.getDynamicSamplingContext();
	addHeadersToRequestOptions(requestOptions, requestUrl, sentryTraceHeader, dynamicSamplingContext);
	} else {
	const client = hub.getClient();
	const { traceId, sampled, dsc } = scope.getPropagationContext();
	const sentryTraceHeader = generateSentryTraceHeader(traceId, undefined, sampled);
	const dynamicSamplingContext =
	dsc || (client ? getDynamicSamplingContextFromClient(traceId, client, scope) : undefined);
	addHeadersToRequestOptions(requestOptions, requestUrl, sentryTraceHeader, dynamicSamplingContext);
	}
	} else {
	__DEBUG_BUILD__ &&
	logger.log(
	`[Tracing] Not adding sentry-trace header to outgoing request (${requestUrl}) due to mismatching tracePropagationTargets option.`,
	);
	}

Essentially if a span does not exist (because no performance or span not sampled), then grab tracing information from scope.getPropagationContext and generate a sentry-trace and baggage header accordingly.

Closing this issue because docs were merged in.