feat: Propagate and use a sampling random

dev-packages/browser-integration-tests/suites/public-api/startSpan/parallel-root-spans-with-parentSpanId/subject.js

@@ -1,6 +1,7 @@
 Sentry.getCurrentScope().setPropagationContext({
   parentSpanId: '1234567890123456',
   traceId: '12345678901234567890123456789012',
+  sampleRand: Math.random(),
 });
 
 Sentry.startSpan({ name: 'test_span_1' }, () => undefined);

dev-packages/browser-integration-tests/suites/public-api/startSpan/standalone-mixed-transaction/test.ts

@@ -47,6 +47,7 @@ sentryTest(
         sampled: 'true',
         trace_id: traceId,
         transaction: 'outer',
+        sample_rand: expect.any(String),
       },
     });
 
@@ -64,6 +65,7 @@ sentryTest(
         sampled: 'true',
         trace_id: traceId,
         transaction: 'outer',
+        sample_rand: expect.any(String),
       },
     });
 

dev-packages/browser-integration-tests/suites/public-api/startSpan/standalone/test.ts

@@ -33,6 +33,7 @@ sentryTest('sends a segment span envelope', async ({ getLocalTestUrl, page }) =>
       sampled: 'true',
       trace_id: traceId,
       transaction: 'standalone_segment_span',
+      sample_rand: expect.any(String),
     },
   });
 

dev-packages/browser-integration-tests/suites/replay/dsc/test.ts

@@ -62,6 +62,7 @@ sentryTest(
       public_key: 'public',
       replay_id: replay.session?.id,
       sampled: 'true',
+      sample_rand: expect.any(String),
     });
   },
 );
@@ -108,6 +109,7 @@ sentryTest(
       trace_id: expect.stringMatching(/[a-f0-9]{32}/),
       public_key: 'public',
       sampled: 'true',
+      sample_rand: expect.any(String),
     });
   },
 );
@@ -161,6 +163,7 @@ sentryTest(
       public_key: 'public',
       replay_id: replay.session?.id,
       sampled: 'true',
+      sample_rand: expect.any(String),
     });
   },
 );
@@ -202,6 +205,7 @@ sentryTest(
       trace_id: expect.stringMatching(/[a-f0-9]{32}/),
       public_key: 'public',
       sampled: 'true',
+      sample_rand: expect.any(String),
     });
   },
 );
@@ -247,6 +251,7 @@ sentryTest('should add replay_id to error DSC while replay is active', async ({
       ? {
           sample_rate: '1',
           sampled: 'true',
+          sample_rand: expect.any(String),
         }
       : {}),
   });
@@ -267,6 +272,7 @@ sentryTest('should add replay_id to error DSC while replay is active', async ({
       ? {
           sample_rate: '1',
           sampled: 'true',
+          sample_rand: expect.any(String),
         }
       : {}),
   });

dev-packages/browser-integration-tests/suites/tracing/browserTracingIntegration/meta/template.html

@@ -5,7 +5,7 @@
     <meta name="sentry-trace" content="12312012123120121231201212312012-1121201211212012-1" />
     <meta
       name="baggage"
-      content="sentry-release=2.1.12,sentry-public_key=public,sentry-trace_id=123,sentry-sample_rate=0.3232"
+      content="sentry-release=2.1.12,sentry-public_key=public,sentry-trace_id=123,sentry-sample_rate=0.3232,sentry-sample_rand=0.42"
     />
   </head>
 </html>

dev-packages/browser-integration-tests/suites/tracing/browserTracingIntegration/meta/test.ts

@@ -43,6 +43,7 @@ sentryTest(
       sample_rate: '0.3232',
       trace_id: '123',
       public_key: 'public',
+      sample_rand: '0.42',
     });
   },
 );

dev-packages/browser-integration-tests/suites/tracing/dsc-txn-name-update/test.ts

@@ -48,6 +48,7 @@ sentryTest('updates the DSC when the txn name is updated and high-quality', asyn
     'sentry-environment=production',
     'sentry-public_key=public',
     'sentry-release=1.1.1',
+    expect.stringMatching(/sentry-sample_rand=0\.[0-9]+/),
     'sentry-sample_rate=1',
     'sentry-sampled=true',
     `sentry-trace_id=${traceId}`,
@@ -62,6 +63,7 @@ sentryTest('updates the DSC when the txn name is updated and high-quality', asyn
     sample_rate: '1',
     sampled: 'true',
     trace_id: traceId,
+    sample_rand: expect.any(String),
   });
 
   // 4
@@ -73,6 +75,7 @@ sentryTest('updates the DSC when the txn name is updated and high-quality', asyn
     'sentry-environment=production',
     'sentry-public_key=public',
     'sentry-release=1.1.1',
+    expect.stringMatching(/sentry-sample_rand=0\.[0-9]+/),
     'sentry-sample_rate=1',
     'sentry-sampled=true',
     `sentry-trace_id=${traceId}`,
@@ -89,6 +92,7 @@ sentryTest('updates the DSC when the txn name is updated and high-quality', asyn
     sampled: 'true',
     trace_id: traceId,
     transaction: 'updated-root-span-1',
+    sample_rand: expect.any(String),
   });
 
   // 7
@@ -100,6 +104,7 @@ sentryTest('updates the DSC when the txn name is updated and high-quality', asyn
     'sentry-environment=production',
     'sentry-public_key=public',
     'sentry-release=1.1.1',
+    expect.stringMatching(/sentry-sample_rand=0\.[0-9]+/),
     'sentry-sample_rate=1',
     'sentry-sampled=true',
     `sentry-trace_id=${traceId}`,
@@ -116,6 +121,7 @@ sentryTest('updates the DSC when the txn name is updated and high-quality', asyn
     sampled: 'true',
     trace_id: traceId,
     transaction: 'updated-root-span-2',
+    sample_rand: expect.any(String),
   });
 
   // 10
@@ -137,6 +143,7 @@ sentryTest('updates the DSC when the txn name is updated and high-quality', asyn
     sampled: 'true',
     trace_id: traceId,
     transaction: 'updated-root-span-2',
+    sample_rand: expect.any(String),
   });
 
   expect(txnEvent.transaction).toEqual('updated-root-span-2');

dev-packages/browser-integration-tests/suites/tracing/envelope-header-transaction-name/test.ts

@@ -27,6 +27,7 @@ sentryTest(
       trace_id: expect.stringMatching(/[a-f0-9]{32}/),
       public_key: 'public',
       sampled: 'true',
+      sample_rand: expect.any(String),
     });
   },
 );

dev-packages/browser-integration-tests/suites/tracing/envelope-header/test.ts

@@ -30,6 +30,7 @@ sentryTest(
       trace_id: expect.stringMatching(/[a-f0-9]{32}/),
       public_key: 'public',
       sampled: 'true',
+      sample_rand: expect.any(String),
     });
   },
 );

dev-packages/browser-integration-tests/suites/tracing/metrics/web-vitals-cls-standalone-spans/test.ts

@@ -100,6 +100,7 @@ sentryTest('captures a "GOOD" CLS vital with its source as a standalone span', a
       sample_rate: '1',
       sampled: 'true',
       trace_id: spanEnvelopeItem.trace_id,
+      sample_rand: expect.any(String),
       // no transaction, because span source is URL
     },
   });
@@ -167,6 +168,7 @@ sentryTest('captures a "MEH" CLS vital with its source as a standalone span', as
       sample_rate: '1',
       sampled: 'true',
       trace_id: spanEnvelopeItem.trace_id,
+      sample_rand: expect.any(String),
       // no transaction, because span source is URL
     },
   });
@@ -232,6 +234,7 @@ sentryTest('captures a "POOR" CLS vital with its source as a standalone span.',
       sample_rate: '1',
       sampled: 'true',
       trace_id: spanEnvelopeItem.trace_id,
+      sample_rand: expect.any(String),
       // no transaction, because span source is URL
     },
   });
@@ -294,6 +297,7 @@ sentryTest(
         sample_rate: '1',
         sampled: 'true',
         trace_id: spanEnvelopeItem.trace_id,
+        sample_rand: expect.any(String),
         // no transaction, because span source is URL
       },
     });

dev-packages/browser-integration-tests/suites/tracing/metrics/web-vitals-inp-late/test.ts

@@ -55,6 +55,7 @@ sentryTest('should capture an INP click event span after pageload', async ({ bro
       sample_rate: '1',
       sampled: 'true',
       trace_id: traceId,
+      sample_rand: expect.any(String),
     },
   });
 

dev-packages/browser-integration-tests/suites/tracing/metrics/web-vitals-inp-parametrized-late/test.ts

@@ -58,6 +58,7 @@ sentryTest(
         sampled: 'true',
         trace_id: traceId,
         transaction: 'test-route',
+        sample_rand: expect.any(String),
       },
     });
 

dev-packages/browser-integration-tests/suites/tracing/metrics/web-vitals-inp-parametrized/test.ts

@@ -56,6 +56,7 @@ sentryTest(
         sampled: 'true',
         trace_id: traceId,
         transaction: 'test-route',
+        sample_rand: expect.any(String),
       },
     });
 

dev-packages/browser-integration-tests/suites/tracing/metrics/web-vitals-inp/test.ts

@@ -54,6 +54,7 @@ sentryTest('should capture an INP click event span during pageload', async ({ br
       sample_rate: '1',
       sampled: 'true',
       trace_id: traceId,
+      sample_rand: expect.any(String),
       // no transaction, because span source is URL
     },
   });

dev-packages/browser-integration-tests/suites/tracing/trace-lifetime/navigation/test.ts

@@ -10,7 +10,7 @@ import {
   shouldSkipTracingTest,
 } from '../../../../utils/helpers';
 
-sentryTest('creates a new trace on each navigation', async ({ getLocalTestUrl, page }) => {
+sentryTest('creates a new trace and sample_rand on each navigation', async ({ getLocalTestUrl, page }) => {
   if (shouldSkipTracingTest()) {
     sentryTest.skip();
   }
@@ -49,6 +49,7 @@ sentryTest('creates a new trace on each navigation', async ({ getLocalTestUrl, p
     sample_rate: '1',
     sampled: 'true',
     trace_id: navigation1TraceContext?.trace_id,
+    sample_rand: expect.any(String),
   });
 
   expect(navigation2TraceContext).toMatchObject({
@@ -64,9 +65,11 @@ sentryTest('creates a new trace on each navigation', async ({ getLocalTestUrl, p
     sample_rate: '1',
     sampled: 'true',
     trace_id: navigation2TraceContext?.trace_id,
+    sample_rand: expect.any(String),
   });
 
   expect(navigation1TraceContext?.trace_id).not.toEqual(navigation2TraceContext?.trace_id);
+  expect(navigation1TraceHeader?.sample_rand).not.toEqual(navigation2TraceHeader?.sample_rand);
 });
 
 sentryTest('error after navigation has navigation traceId', async ({ getLocalTestUrl, page }) => {
@@ -101,6 +104,7 @@ sentryTest('error after navigation has navigation traceId', async ({ getLocalTes
     sample_rate: '1',
     sampled: 'true',
     trace_id: navigationTraceContext?.trace_id,
+    sample_rand: expect.any(String),
   });
 
   const errorEventPromise = getFirstSentryEnvelopeRequest<EventAndTraceHeader>(
@@ -124,6 +128,7 @@ sentryTest('error after navigation has navigation traceId', async ({ getLocalTes
     sample_rate: '1',
     sampled: 'true',
     trace_id: navigationTraceContext?.trace_id,
+    sample_rand: expect.any(String),
   });
 });
 
@@ -168,6 +173,7 @@ sentryTest('error during navigation has new navigation traceId', async ({ getLoc
     sample_rate: '1',
     sampled: 'true',
     trace_id: navigationTraceContext?.trace_id,
+    sample_rand: expect.any(String),
   });
 
   const errorTraceContext = errorEvent?.contexts?.trace;
@@ -182,6 +188,7 @@ sentryTest('error during navigation has new navigation traceId', async ({ getLoc
     sample_rate: '1',
     sampled: 'true',
     trace_id: navigationTraceContext?.trace_id,
+    sample_rand: expect.any(String),
   });
 });
 
@@ -234,6 +241,7 @@ sentryTest(
       sample_rate: '1',
       sampled: 'true',
       trace_id: navigationTraceContext?.trace_id,
+      sample_rand: expect.any(String),
     });
 
     const headers = request.headers();
@@ -242,7 +250,7 @@ sentryTest(
     const navigationTraceId = navigationTraceContext?.trace_id;
     expect(headers['sentry-trace']).toMatch(new RegExp(`^${navigationTraceId}-[0-9a-f]{16}-1$`));
     expect(headers['baggage']).toEqual(
-      `sentry-environment=production,sentry-public_key=public,sentry-trace_id=${navigationTraceId},sentry-sample_rate=1,sentry-sampled=true`,
+      `sentry-environment=production,sentry-public_key=public,sentry-trace_id=${navigationTraceId},sentry-sample_rate=1,sentry-sampled=true,sentry-sample_rand=${navigationTraceHeader?.sample_rand}`,
     );
   },
 );
@@ -296,6 +304,7 @@ sentryTest(
       sample_rate: '1',
       sampled: 'true',
       trace_id: navigationTraceContext?.trace_id,
+      sample_rand: expect.any(String),
     });
 
     const headers = request.headers();
@@ -304,7 +313,7 @@ sentryTest(
     const navigationTraceId = navigationTraceContext?.trace_id;
     expect(headers['sentry-trace']).toMatch(new RegExp(`^${navigationTraceId}-[0-9a-f]{16}-1$`));
     expect(headers['baggage']).toEqual(
-      `sentry-environment=production,sentry-public_key=public,sentry-trace_id=${navigationTraceId},sentry-sample_rate=1,sentry-sampled=true`,
+      `sentry-environment=production,sentry-public_key=public,sentry-trace_id=${navigationTraceId},sentry-sample_rate=1,sentry-sampled=true,sentry-sample_rand=${navigationTraceHeader?.sample_rand}`,
     );
   },
 );

dev-packages/browser-integration-tests/suites/tracing/trace-lifetime/pageload-meta/template.html

@@ -4,7 +4,7 @@
     <meta charset="utf-8" />
     <meta name="sentry-trace" content="12345678901234567890123456789012-1234567890123456-1" />
     <meta name="baggage"
-          content="sentry-trace_id=12345678901234567890123456789012,sentry-sample_rate=0.2,sentry-sampled=true,sentry-transaction=my-transaction,sentry-public_key=public,sentry-release=1.0.0,sentry-environment=prod"/>
+          content="sentry-trace_id=12345678901234567890123456789012,sentry-sample_rate=0.2,sentry-sampled=true,sentry-transaction=my-transaction,sentry-public_key=public,sentry-release=1.0.0,sentry-environment=prod,sentry-sample_rand=0.42"/>
   </head>
   <body>
     <button id="errorBtn">Throw Error</button>