feat(profiling): profiling for trace lifecycle

src/Profiling/ContinuousProfiler.php

@@ -54,6 +54,11 @@ final class ContinuousProfiler
      */
     private $sampled;
 
+    /**
+     * @var array<string, true> The span IDs of the sampled root spans the profiler is running for
+     */
+    private $activeRootSpans = [];
+
     /**
      * @var int
      */
@@ -132,6 +137,31 @@ public function start(): void
         $profiler->start();
     }
 
+    /**
+     * Starts the profiler for a sampled root span, it keeps running until all of them are finished.
+     */
+    public function startForRootSpan(string $spanId): void
+    {
+        $this->start();
+
+        if ($this->profiler !== null) {
+            $this->activeRootSpans[$spanId] = true;
+        }
+    }
+
+    public function stopForRootSpan(string $spanId): void
+    {
+        if (!isset($this->activeRootSpans[$spanId])) {
+            return;
+        }
+
+        unset($this->activeRootSpans[$spanId]);
+
+        if ($this->activeRootSpans === []) {
+            $this->stop();
+        }
+    }
+
     public function stop(): void
     {
         if ($this->profiler === null) {
@@ -146,6 +176,7 @@ public function stop(): void
         $this->profiler = null;
         $this->profilerId = null;
         $this->startTimestamp = null;
+        $this->activeRootSpans = [];
     }
 
     public function isRunning(): bool

src/State/Hub.php

@@ -15,6 +15,8 @@
 use Sentry\EventId;
 use Sentry\Integration\IntegrationInterface;
 use Sentry\MonitorConfig;
+use Sentry\Profiling\ProfileChunk;
+use Sentry\Profiling\Profiles;
 use Sentry\Severity;
 use Sentry\Tracing\SamplingContext;
 use Sentry\Tracing\Span;
@@ -282,6 +284,10 @@ public function startTransaction(TransactionContext $context, array $customSampl
 
             $logger->warning(\sprintf('Transaction [%s] was started but tracing is not enabled.', (string) $transaction->getTraceId()), ['context' => $context]);
 
+            if ($options !== null && $options->getProfileLifecycle() === 'trace') {
+                $logger->warning('The "profile_lifecycle" option is set to "trace" but tracing is not enabled, so no profiles will be collected.');
+            }
+
             return $transaction;
         }
 
@@ -354,6 +360,22 @@ public function startTransaction(TransactionContext $context, array $customSampl
 
         $transaction->initSpanRecorder();
 
+        if ($options->getProfileLifecycle() === 'trace') {
+            $continuousProfiler = Profiles::getInstance()->continuousProfiler();
+            $continuousProfiler->startForRootSpan((string) $transaction->getSpanId());
+
+            $profilerId = $continuousProfiler->getProfilerId();
+
+            // Backfill profiling data because the profiler was started after the transaction
+            if ($profilerId !== null) {
+                $transaction->setData([
+                    'thread.id' => ProfileChunk::THREAD_ID,
+                    'thread.name' => ProfileChunk::THREAD_NAME,
+                    'profiler_id' => $profilerId,
+                ]);
+            }
+        }
+
         $profilesSampleSource = 'config:profiles_sample_rate';
         $profilesSampler = $options->getProfilesSampler();
 

src/Tracing/Transaction.php

@@ -7,6 +7,7 @@
 use Sentry\Event;
 use Sentry\EventId;
 use Sentry\Profiling\Profiler;
+use Sentry\Profiling\Profiles;
 use Sentry\SentrySdk;
 use Sentry\State\HubInterface;
 
@@ -152,6 +153,8 @@ public function finish(?float $endTimestamp = null): ?EventId
             $this->profiler->stop();
         }
 
+        Profiles::getInstance()->continuousProfiler()->stopForRootSpan((string) $this->getSpanId());
+
         if ($this->endTimestamp !== null) {
             // Transaction was already finished once and we don't want to re-flush it
             return null;

tests/State/HubTest.php

@@ -9,6 +9,7 @@
 use Sentry\Breadcrumb;
 use Sentry\CheckIn;
 use Sentry\CheckInStatus;
+use Sentry\Client;
 use Sentry\ClientInterface;
 use Sentry\Event;
 use Sentry\EventHint;
@@ -17,10 +18,14 @@
 use Sentry\MonitorConfig;
 use Sentry\MonitorSchedule;
 use Sentry\Options;
+use Sentry\Profiling\Profiles;
+use Sentry\SentrySdk;
 use Sentry\Severity;
 use Sentry\State\Hub;
+use Sentry\State\HubInterface;
 use Sentry\State\Scope;
 use Sentry\Tests\StubLogger;
+use Sentry\Tests\StubTransport;
 use Sentry\Tracing\DynamicSamplingContext;
 use Sentry\Tracing\PropagationContext;
 use Sentry\Tracing\SamplingContext;
@@ -1115,4 +1120,98 @@ public function testEventTraceContextIsNotOverridenWhenPresent(): void
             $this->assertEquals($event->getContexts()['trace'], $traceContext);
         });
     }
+
+    /**
+     * @requires extension excimer
+     */
+    public function testStartTransactionProfilesSampledTransactionsInTraceLifecycle(): void
+    {
+        StubTransport::$events = [];
+
+        $hub = $this->initHubWithProfileLifecycleTrace();
+        $profiler = Profiles::getInstance()->continuousProfiler();
+
+        $transaction = $hub->startTransaction(TransactionContext::make());
+
+        $this->assertTrue($profiler->isRunning());
+
+        $profilerId = $profiler->getProfilerId();
+
+        $this->assertSame($profilerId, $transaction->getData('profiler_id'));
+
+        self::busyWait(0.05);
+
+        $transaction->finish();
+
+        $this->assertFalse($profiler->isRunning());
+        $this->assertCount(2, StubTransport::$events);
+
+        [$chunkEvent, $transactionEvent] = StubTransport::$events;
+
+        $this->assertNotNull($chunkEvent->getProfileChunk());
+        $this->assertSame($profilerId, $chunkEvent->getProfileChunk()->getProfilerId());
+        $this->assertSame(['profiler_id' => $profilerId], $transactionEvent->getContexts()['profile']);
+    }
+
+    /**
+     * @requires extension excimer
+     */
+    public function testContinuousProfilerRunsUntilTheLastSampledTransactionIsFinished(): void
+    {
+        StubTransport::$events = [];
+
+        $hub = $this->initHubWithProfileLifecycleTrace();
+        $profiler = Profiles::getInstance()->continuousProfiler();
+
+        $firstTransaction = $hub->startTransaction(TransactionContext::make());
+        $secondTransaction = $hub->startTransaction(TransactionContext::make());
+
+        $profilerId = $profiler->getProfilerId();
+
+        self::busyWait(0.05);
+        $firstFinishTimestamp = microtime(true);
+
+        $firstTransaction->finish();
+
+        $this->assertTrue($profiler->isRunning());
+        $this->assertSame($profilerId, $profiler->getProfilerId());
+
+        self::busyWait(0.05);
+
+        $secondTransaction->finish();
+
+        $this->assertFalse($profiler->isRunning());
+
+        $chunkEvents = array_values(array_filter(StubTransport::$events, static function (Event $event): bool {
+            return $event->getProfileChunk() !== null;
+        }));
+
+        $this->assertCount(1, $chunkEvents);
+
+        $payload = $chunkEvents[0]->getProfileChunk()->getFormattedData($chunkEvents[0]);
+
+        $this->assertNotNull($payload);
+        $this->assertLessThan($firstFinishTimestamp, $payload['profile']['samples'][0]['timestamp']);
+    }
+
+    private function initHubWithProfileLifecycleTrace(): HubInterface
+    {
+        $hub = SentrySdk::init();
+        $hub->bindClient(new Client(new Options([
+            'traces_sample_rate' => 1.0,
+            'profile_lifecycle' => 'trace',
+            'profile_session_sample_rate' => 1.0,
+        ]), StubTransport::getInstance()));
+
+        return $hub;
+    }
+
+    private static function busyWait(float $seconds): void
+    {
+        $end = microtime(true) + $seconds;
+
+        while (microtime(true) < $end) {
+            // Burn CPU so that Excimer collects samples
+        }
+    }
 }