fix: Ensure DSC is correct

Author: mydea

packages/core/src/baseclient.ts

@@ -414,7 +414,7 @@ export abstract class BaseClient<O extends ClientOptions> implements Client<O> {
   public on(hook: 'beforeAddBreadcrumb', callback: (breadcrumb: Breadcrumb, hint?: BreadcrumbHint) => void): void;
 
   /** @inheritdoc */
-  public on(hook: 'createDsc', callback: (dsc: DynamicSamplingContext) => void): void;
+  public on(hook: 'createDsc', callback: (dsc: DynamicSamplingContext, rootSpan?: Span) => void): void;
 
   /** @inheritdoc */
   public on(
@@ -499,7 +499,7 @@ export abstract class BaseClient<O extends ClientOptions> implements Client<O> {
   public emit(hook: 'beforeAddBreadcrumb', breadcrumb: Breadcrumb, hint?: BreadcrumbHint): void;
 
   /** @inheritdoc */
-  public emit(hook: 'createDsc', dsc: DynamicSamplingContext): void;
+  public emit(hook: 'createDsc', dsc: DynamicSamplingContext, rootSpan?: Span): void;
 
   /** @inheritdoc */
   public emit(hook: 'beforeSendFeedback', feedback: FeedbackEvent, options?: { includeReplay: boolean }): void;

packages/core/src/tracing/dynamicSamplingContext.ts

@@ -105,7 +105,7 @@ export function getDynamicSamplingContextFromSpan(span: Span): Readonly<Partial<
 
   dsc.sampled = String(spanIsSampled(rootSpan));
 
-  client.emit('createDsc', dsc);
+  client.emit('createDsc', dsc, rootSpan);
 
   return dsc;
 }

packages/node/src/sdk/index.ts

@@ -14,6 +14,7 @@ import {
 import {
   openTelemetrySetupCheck,
   setOpenTelemetryContextAsyncContextStrategy,
+  setupDscHandler,
   setupEventContextTrace,
 } from '@sentry/opentelemetry';
 import type { Client, Integration, Options } from '@sentry/types';
@@ -175,6 +176,7 @@ function _init(
     validateOpenTelemetrySetup();
   }
 
+  setupDscHandler(client);
   setupEventContextTrace(client);
 }
 

packages/opentelemetry/src/index.ts

@@ -21,6 +21,8 @@ export { getDynamicSamplingContextFromSpan } from '@sentry/core';
 
 export { isSentryRequestSpan } from './utils/isSentryRequest';
 
+export { setupDscHandler } from './utils/setupDscHandler';
+
 export { getActiveSpan } from './utils/getActiveSpan';
 export { startSpan, startSpanManual, startInactiveSpan, withActiveSpan, continueTrace } from './trace';
 

packages/opentelemetry/src/utils/setupDscHandler.ts

@@ -0,0 +1,27 @@
+import { SEMANTIC_ATTRIBUTE_SENTRY_SOURCE, spanToJSON } from '@sentry/core';
+import type { Client } from '@sentry/types';
+import { parseSpanDescription } from './parseSpanDescription';
+import { spanHasName } from './spanTypes';
+
+/**
+ * Setup a DSC handler on the passed client, ensuring that the transaction name is inferred from the span correctly.
+ */
+export function setupDscHandler(client: Client): void {
+  client.on('createDsc', (dsc, rootSpan) => {
+    // We want to overwrite the transaction on the DSC that is created by default in core
+    // The reason for this is that we want to infer the span name, not use the initial one
+    // Otherwise, we'll get names like "GET" instead of e.g. "GET /foo"
+    // `parseSpanDescription` takes the attributes of the span into account for the name
+    // This mutates the passed-in DSC
+    if (rootSpan) {
+      const jsonSpan = spanToJSON(rootSpan);
+      const attributes = jsonSpan.data || {};
+      const source = attributes[SEMANTIC_ATTRIBUTE_SENTRY_SOURCE];
+
+      const { description } = spanHasName(rootSpan) ? parseSpanDescription(rootSpan) : { description: undefined };
+      if (source !== 'url' && description) {
+        dsc.transaction = description;
+      }
+    }
+  });
+}

packages/types/src/client.ts

@@ -244,7 +244,7 @@ export interface Client<O extends ClientOptions = ClientOptions> {
   /**
    * Register a callback when a DSC (Dynamic Sampling Context) is created.
    */
-  on(hook: 'createDsc', callback: (dsc: DynamicSamplingContext) => void): void;
+  on(hook: 'createDsc', callback: (dsc: DynamicSamplingContext, rootSpan?: Span) => void): void;
 
   /**
    * Register a callback when a Feedback event has been prepared.
@@ -338,7 +338,7 @@ export interface Client<O extends ClientOptions = ClientOptions> {
   /**
    * Fire a hook for when a DSC (Dynamic Sampling Context) is created. Expects the DSC as second argument.
    */
-  emit(hook: 'createDsc', dsc: DynamicSamplingContext): void;
+  emit(hook: 'createDsc', dsc: DynamicSamplingContext, rootSpan?: Span): void;
 
   /**
    * Fire a hook event for after preparing a feedback event. Events to be given