`@sentry/node` should not have a direct dependency on `@sentry/tracing`

[timfish]

Problem Statement

It seems like @sentry/tracing is a direct dependency of @sentry/node due to only this single line:

sentry-javascript/packages/node/src/handlers.ts

Line 4 in 8cbcff2

import { extractTraceparentData, Span } from '@sentry/tracing';

This has a number of downsides:

• There are side effects that users will be unaware of
• The Node performance docs are outdated saying you need to import @sentry/tracing
• @sentry/tracing now accounts for nearly 50% of the Node SDK init time
  • Run this to get cpu profile: node --cpu-prof -e "require('@sentry/node').init({dsn:'http://some@real.dsn/123'})"

Solution Brainstorm

Inline that code?

[AbhiPrasad]

Applying this patch should fix it, we need to move extractTraceparentData to utils though (and then make the tracing import just reference that for backwards compatibility reasons).

diff --git a/packages/node/package.json b/packages/node/package.json
index 8689b74a..222c55cf 100644
--- a/packages/node/package.json
+++ b/packages/node/package.json
@@ -18,7 +18,6 @@
   "dependencies": {
     "@sentry/core": "6.18.0",
     "@sentry/hub": "6.18.0",
-    "@sentry/tracing": "6.18.0",
     "@sentry/types": "6.18.0",
     "@sentry/utils": "6.18.0",
     "cookie": "^0.4.1",
diff --git a/packages/node/src/handlers.ts b/packages/node/src/handlers.ts
index 6604dfff..1d08dab1 100644
--- a/packages/node/src/handlers.ts
+++ b/packages/node/src/handlers.ts
@@ -1,9 +1,15 @@
 /* eslint-disable max-lines */
 /* eslint-disable @typescript-eslint/no-explicit-any */
 import { captureException, getCurrentHub, startTransaction, withScope } from '@sentry/core';
-import { extractTraceparentData, Span } from '@sentry/tracing';
-import { Event, ExtractedNodeRequestData, Transaction } from '@sentry/types';
-import { isPlainObject, isString, logger, normalize, stripUrlQueryAndFragment } from '@sentry/utils';
+import { Event, ExtractedNodeRequestData, Span, Transaction } from '@sentry/types';
+import {
+  extractTraceparentData,
+  isPlainObject,
+  isString,
+  logger,
+  normalize,
+  stripUrlQueryAndFragment,
+} from '@sentry/utils';
 import * as cookie from 'cookie';
 import * as domain from 'domain';
 import * as http from 'http';

With that, we can probably drop the dependency.

@getsentry/team-web-frontend does that seem like a reasonable change to you folks?

[AbhiPrasad]

Alright let's go ahead and make these changes. It'll come in two steps.

1. Port the extractTraceparentData function into utils and update the tracing package to use that
2. Update node and remove the tracing dependency.

[AbhiPrasad]

Hmm this might actually be non-trivial though. Removing the export means that the hub no longer gets patched with startTransaction, so it might break users who (incorrectly) did not import @sentry/tracing for the side effect. Hence, even it'll be a bad experience for the users - even if they are not using the SDK and tracing as intended.

Is it worthwhile to still make the change?

[AbhiPrasad]

We're gonna go ahead with these changes - especially since our documentation clearly indicates you need @sentry/tracing imported for the side effect.