From ec56114e46e4ce923a2dffe36e89fdd4157697fc Mon Sep 17 00:00:00 2001
From: Jonathan Alvarado <jonathan.alvarado@sourceability.com>
Date: Wed, 29 Nov 2023 09:50:30 -0600
Subject: [PATCH 1/2] Respect Datadog DD_TRACE_SAMPLE_RATE rate limiting
 environment variable

---
 src/Profiler/DatadogProfiler.php | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/src/Profiler/DatadogProfiler.php b/src/Profiler/DatadogProfiler.php
index 2ca68cc..e510d3f 100644
--- a/src/Profiler/DatadogProfiler.php
+++ b/src/Profiler/DatadogProfiler.php
@@ -21,10 +21,19 @@ class DatadogProfiler implements ProfilerInterface
     private ?Scope $scope = null;
 
     private LoggerInterface $logger;
+    private ?float $sampleRate;
 
     public function __construct(LoggerInterface $logger)
     {
         $this->logger = $logger;
+
+        $sampleRateString = getenv('DD_TRACE_SAMPLE_RATE');
+        if(is_numeric($sampleRateString)) {
+            $sampleRate = floatval($sampleRateString);
+            $this->sampleRate = $sampleRate;
+        } else {
+            $this->sampleRate = null;
+        }
     }
 
     public function start(string $name, ?string $kind = null): void
@@ -33,6 +42,10 @@ public function start(string $name, ?string $kind = null): void
             return;
         }
 
+        if($this->rateLimited()) {
+            return;
+        }
+
         if (dd_trace_env_config('DD_TRACE_GENERATE_ROOT_SPAN')) {
             $this->logger->error(
                 sprintf('You should set DD_TRACE_GENERATE_ROOT_SPAN=0 when using %s.', self::class)
@@ -89,6 +102,15 @@ public function stopAndIgnore(): void
         GlobalTracer::set(new Tracer());
     }
 
+    private function rateLimited(): bool
+    {
+        if($this->sampleRate) {
+            $randomFloat = mt_rand() / mt_getrandmax(); // between 0 and 1
+            return $randomFloat > $this->sampleRate;
+        }  
+        return false;
+    }
+
     private function isEnabled(): bool
     {
         return \extension_loaded('ddtrace')

From ae641fa07aad7a3c93c8557a108a5f078be25933 Mon Sep 17 00:00:00 2001
From: Jonathan Alvarado <jonathan.alvarado@sourceability.com>
Date: Wed, 29 Nov 2023 10:21:47 -0600
Subject: [PATCH 2/2] Set default to 1.0

---
 src/Profiler/DatadogProfiler.php | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/src/Profiler/DatadogProfiler.php b/src/Profiler/DatadogProfiler.php
index e510d3f..ea478a4 100644
--- a/src/Profiler/DatadogProfiler.php
+++ b/src/Profiler/DatadogProfiler.php
@@ -21,7 +21,8 @@ class DatadogProfiler implements ProfilerInterface
     private ?Scope $scope = null;
 
     private LoggerInterface $logger;
-    private ?float $sampleRate;
+
+    private float $sampleRate = 1.0;
 
     public function __construct(LoggerInterface $logger)
     {
@@ -31,8 +32,6 @@ public function __construct(LoggerInterface $logger)
         if(is_numeric($sampleRateString)) {
             $sampleRate = floatval($sampleRateString);
             $this->sampleRate = $sampleRate;
-        } else {
-            $this->sampleRate = null;
         }
     }
 
@@ -104,11 +103,8 @@ public function stopAndIgnore(): void
 
     private function rateLimited(): bool
     {
-        if($this->sampleRate) {
-            $randomFloat = mt_rand() / mt_getrandmax(); // between 0 and 1
-            return $randomFloat > $this->sampleRate;
-        }  
-        return false;
+        $randomFloat = mt_rand() / mt_getrandmax(); // between 0 and 1
+        return $randomFloat > $this->sampleRate;
     }
 
     private function isEnabled(): bool