Allow profiler to start before SDK and transaction is initialized

src/Profiling/Profiler.php

@@ -16,7 +16,12 @@ final class Profiler
     /**
      * @var \ExcimerProfiler|null
      */
-    private $profiler;
+    private static $profiler;
+
+    /**
+     * @var float|null
+     */
+    private static $startedAt;
 
     /**
      * @var Profile
@@ -48,23 +53,39 @@ public function __construct(?Options $options = null)
 
     public function start(): void
     {
-        if ($this->profiler !== null) {
-            $this->profiler->start();
+        if (self::$profiler === null) {
+            return;
+        }
+
+        // Prevent starting the profiler multiple times since that will discard the previous data
+        // If you need to "restart" profiling, stop first to remove data and start again to start fresh
+        if (self::$startedAt !== null) {
+            return;
         }
+
+        self::startProfiling();
     }
 
     public function stop(): void
     {
-        if ($this->profiler !== null) {
-            $this->profiler->stop();
+        if (self::$profiler === null) {
+            return;
+        }
+
+        self::$profiler->stop();
+
+        $this->profile->setExcimerLog(self::$profiler->flush());
 
-            $this->profile->setExcimerLog($this->profiler->flush());
+        if (self::$startedAt !== null) {
+            $this->profile->setStartTimeStamp(self::$startedAt);
+
+            self::$startedAt = null;
         }
     }
 
     public function getProfile(): ?Profile
     {
-        if ($this->profiler === null) {
+        if (self::$profiler === null) {
             return null;
         }
 
@@ -73,17 +94,67 @@ public function getProfile(): ?Profile
 
     private function initProfiler(): void
     {
-        if (!\extension_loaded('excimer')) {
+        if (self::$startedAt !== null) {
+            $this->logger->debug('The profiler was already started, will continue profiling.', ['started_at' => self::$startedAt]);
+
+            $this->profile->setStartTimeStamp(self::$startedAt);
+
+            return;
+        }
+
+        self::setupProfiler();
+
+        if (self::$profiler === null) {
             $this->logger->warning('The profiler was started but is not available because the "excimer" extension is not loaded.');
 
             return;
         }
 
-        $this->profiler = new \ExcimerProfiler();
-        $this->profile->setStartTimeStamp(microtime(true));
+        self::startProfiling();
+    }
+
+    private static function setupProfiler(): void
+    {
+        // Setup is only needed once
+        if (self::$profiler !== null) {
+            return;
+        }
+
+        if (!\extension_loaded('excimer')) {
+            return;
+        }
+
+        $profiler = new \ExcimerProfiler();
+
+        $profiler->setPeriod(self::SAMPLE_RATE);
+        $profiler->setMaxDepth(self::MAX_STACK_DEPTH);
+        $profiler->setEventType(\EXCIMER_REAL);
+
+        self::$profiler = $profiler;
+    }
+
+    public static function startProfiling(): void
+    {
+        self::setupProfiler();
+
+        if (self::$profiler === null) {
+            return;
+        }
+
+        self::$profiler->start();
+        self::$startedAt = microtime(true);
+    }
+
+    public static function maybeDiscardProfilingData(): void
+    {
+        // If we don't have an instance of the profiler there is no data to discard making this a no-op if the profiler was not started
+        if (self::$profiler === null) {
+            return;
+        }
+
+        self::$profiler->stop();
 
-        $this->profiler->setEventType(\EXCIMER_REAL);
-        $this->profiler->setPeriod(self::SAMPLE_RATE);
-        $this->profiler->setMaxDepth(self::MAX_STACK_DEPTH);
+        self::$profiler = null;
+        self::$startedAt = null;
     }
 }

src/State/Hub.php

@@ -14,6 +14,7 @@
 use Sentry\EventId;
 use Sentry\Integration\IntegrationInterface;
 use Sentry\MonitorConfig;
+use Sentry\Profiling\Profiler;
 use Sentry\Severity;
 use Sentry\Tracing\SamplingContext;
 use Sentry\Tracing\Span;
@@ -320,12 +321,16 @@ public function startTransaction(TransactionContext $context, array $customSampl
         $profilesSampleRate = $options->getProfilesSampleRate();
         if ($profilesSampleRate === null) {
             $logger->info(\sprintf('Transaction [%s] is not profiling because `profiles_sample_rate` option is not set.', (string) $transaction->getTraceId()));
+
+            Profiler::maybeDiscardProfilingData();
         } elseif ($this->sample($profilesSampleRate)) {
             $logger->info(\sprintf('Transaction [%s] started profiling because it was sampled.', (string) $transaction->getTraceId()));
 
             $transaction->initProfiler()->start();
         } else {
             $logger->info(\sprintf('Transaction [%s] is not profiling because it was not sampled.', (string) $transaction->getTraceId()));
+
+            Profiler::maybeDiscardProfilingData();
         }
 
         return $transaction;