feat(core): Allow multiplexed transport to send to multiple releases (#8559)

The multiplexed transport can already route events to different or
multiple DSNs but we also need to be able to route to specific releases
too.

In a page with micro-frontends, it's possible (and probably even quite
common) to be using the same dependency multiple times but different
versions (ie. different releases). Depending on where an error occurs we
might want to send an event to `[email protected]` or
`[email protected]` at the same DSN.

This PR:
- Adds a private `makeOverrideReleaseTransport` which can used to wrap a
transport and override the release on all events
- Modifies `makeMultiplexedTransport` so it now creates a transport for
each unique dsn/release pair
- And uses `makeOverrideReleaseTransport` whenever a release is returned
from the callback

Author: timfish

packages/core/src/transports/multiplexed.ts

@@ -24,9 +24,15 @@ interface MatchParam {
   getEvent(types?: EnvelopeItemType[]): Event | undefined;
 }
 
-type Matcher = (param: MatchParam) => string[];
+type RouteTo = { dsn: string; release: string };
+type Matcher = (param: MatchParam) => (string | RouteTo)[];
 
-function eventFromEnvelope(env: Envelope, types: EnvelopeItemType[]): Event | undefined {
+/**
+ * Gets an event from an envelope.
+ *
+ * This is only exported for use in the tests
+ */
+export function eventFromEnvelope(env: Envelope, types: EnvelopeItemType[]): Event | undefined {
   let event: Event | undefined;
 
   forEachEnvelopeItem(env, (item, type) => {
@@ -40,6 +46,30 @@ function eventFromEnvelope(env: Envelope, types: EnvelopeItemType[]): Event | un
   return event;
 }
 
+/**
+ * Creates a transport that overrides the release on all events.
+ */
+function makeOverrideReleaseTransport<TO extends BaseTransportOptions>(
+  createTransport: (options: TO) => Transport,
+  release: string,
+): (options: TO) => Transport {
+  return options => {
+    const transport = createTransport(options);
+
+    return {
+      send: async (envelope: Envelope): Promise<void | TransportMakeRequestResponse> => {
+        const event = eventFromEnvelope(envelope, ['event', 'transaction', 'profile', 'replay_event']);
+
+        if (event) {
+          event.release = release;
+        }
+        return transport.send(envelope);
+      },
+      flush: timeout => transport.flush(timeout),
+    };
+  };
+}
+
 /**
  * Creates a transport that can send events to different DSNs depending on the envelope contents.
  */
@@ -51,17 +81,24 @@ export function makeMultiplexedTransport<TO extends BaseTransportOptions>(
     const fallbackTransport = createTransport(options);
     const otherTransports: Record<string, Transport> = {};
 
-    function getTransport(dsn: string): Transport | undefined {
-      if (!otherTransports[dsn]) {
+    function getTransport(dsn: string, release: string | undefined): Transport | undefined {
+      // We create a transport for every unique dsn/release combination as there may be code from multiple releases in
+      // use at the same time
+      const key = release ? `${dsn}:${release}` : dsn;
+
+      if (!otherTransports[key]) {
         const validatedDsn = dsnFromString(dsn);
         if (!validatedDsn) {
           return undefined;
         }
         const url = getEnvelopeEndpointWithUrlEncodedAuth(validatedDsn);
-        otherTransports[dsn] = createTransport({ ...options, url });
+
+        otherTransports[key] = release
+          ? makeOverrideReleaseTransport(createTransport, release)({ ...options, url })
+          : createTransport({ ...options, url });
       }
 
-      return otherTransports[dsn];
+      return otherTransports[key];
     }
 
     async function send(envelope: Envelope): Promise<void | TransportMakeRequestResponse> {
@@ -71,7 +108,13 @@ export function makeMultiplexedTransport<TO extends BaseTransportOptions>(
       }
 
       const transports = matcher({ envelope, getEvent })
-        .map(dsn => getTransport(dsn))
+        .map(result => {
+          if (typeof result === 'string') {
+            return getTransport(result, undefined);
+          } else {
+            return getTransport(result.dsn, result.release);
+          }
+        })
         .filter((t): t is Transport => !!t);
 
       // If we have no transports to send to, use the fallback transport

packages/core/test/lib/transports/multiplexed.test.ts

@@ -6,10 +6,11 @@ import type {
   TransactionEvent,
   Transport,
 } from '@sentry/types';
-import { createClientReportEnvelope, createEnvelope, dsnFromString } from '@sentry/utils';
-import { TextEncoder } from 'util';
+import { createClientReportEnvelope, createEnvelope, dsnFromString, parseEnvelope } from '@sentry/utils';
+import { TextDecoder, TextEncoder } from 'util';
 
 import { createTransport, getEnvelopeEndpointWithUrlEncodedAuth, makeMultiplexedTransport } from '../../../src';
+import { eventFromEnvelope } from '../../../src/transports/multiplexed';
 
 const DSN1 = 'https://[email protected]/4321';
 const DSN1_URL = getEnvelopeEndpointWithUrlEncodedAuth(dsnFromString(DSN1)!);
@@ -47,7 +48,7 @@ const CLIENT_REPORT_ENVELOPE = createClientReportEnvelope(
   123456,
 );
 
-type Assertion = (url: string, body: string | Uint8Array) => void;
+type Assertion = (url: string, release: string | undefined, body: string | Uint8Array) => void;
 
 const createTestTransport = (...assertions: Assertion[]): ((options: BaseTransportOptions) => Transport) => {
   return (options: BaseTransportOptions) =>
@@ -57,7 +58,10 @@ const createTestTransport = (...assertions: Assertion[]): ((options: BaseTranspo
         if (!assertion) {
           throw new Error('No assertion left');
         }
-        assertion(options.url, request.body);
+
+        const event = eventFromEnvelope(parseEnvelope(request.body, new TextEncoder(), new TextDecoder()), ['event']);
+
+        assertion(options.url, event?.release, request.body);
         resolve({ statusCode: 200 });
       });
     });
@@ -111,6 +115,21 @@ describe('makeMultiplexedTransport', () => {
     await transport.send(ERROR_ENVELOPE);
   });
 
+  it('DSN and release can be overridden via match callback', async () => {
+    expect.assertions(2);
+
+    const makeTransport = makeMultiplexedTransport(
+      createTestTransport((url, release) => {
+        expect(url).toBe(DSN2_URL);
+        expect(release).toBe('[email protected]');
+      }),
+      () => [{ dsn: DSN2, release: '[email protected]' }],
+    );
+
+    const transport = makeTransport({ url: DSN1_URL, ...transportOptions });
+    await transport.send(ERROR_ENVELOPE);
+  });
+
   it('match callback can return multiple DSNs', async () => {
     expect.assertions(2);