Updated implementation to conform specification

src/Instrumentation/PDO/README.md

@@ -45,6 +45,11 @@ or environment variable:
 OTEL_PHP_INSTRUMENTATION_PDO_CONTEXT_PROPAGATION=true
 ```
 
+The context sources from global propagator by default, but it can be configured using the following environment variables:
+```shell
+OTEL_PHP_INSTRUMENTATION_PDO_CONTEXT_PROPAGATORS=tracecontext
+```
+
 The modified query statement by default will not update `DbAttributes::DB_QUERY_TEXT` due to high cardinality risk, but it can be configured using the following configuration directive:
 ```
 otel.instrumentation.pdo.context_propagation.attribute = true

src/Instrumentation/PDO/src/ContextPropagatorFactory.php

@@ -0,0 +1,74 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OpenTelemetry\Contrib\Instrumentation\PDO;
+
+use OpenTelemetry\API\Behavior\LogsMessagesTrait;
+use OpenTelemetry\Context\Propagation\MultiTextMapPropagator;
+use OpenTelemetry\Context\Propagation\NoopTextMapPropagator;
+use OpenTelemetry\Context\Propagation\TextMapPropagatorInterface;
+use OpenTelemetry\SDK\Common\Configuration\Configuration;
+use OpenTelemetry\SDK\Registry;
+
+class ContextPropagatorFactory
+{
+    use LogsMessagesTrait;
+
+    public function create(): TextMapPropagatorInterface | null
+    {
+        $propagators = [];
+        if (class_exists('OpenTelemetry\SDK\Common\Configuration\Configuration')) {
+            $propagators = Configuration::getList('OTEL_PHP_INSTRUMENTATION_PDO_CONTEXT_PROPAGATORS', []);
+        }
+
+        switch (count($propagators)) {
+            case 0:
+                return null;
+            case 1:
+                $propagator = $this->buildPropagator($propagators[0]);
+                if ($propagator !== null && is_a($propagator, NoopTextMapPropagator::class)) {
+                    return null;
+                }
+
+                return $propagator;
+            default:
+                $props = $this->buildPropagators($propagators);
+                if ($props) {
+                    return new MultiTextMapPropagator($props);
+                }
+
+                return null;
+        }
+    }
+
+    /**
+     * @return ?list<TextMapPropagatorInterface>
+     */
+    private function buildPropagators(array $names): ?array
+    {
+        $propagators = [];
+        foreach ($names as $name) {
+            $propagator = $this->buildPropagator($name);
+            if ($propagator !== null && !is_a($propagator, NoopTextMapPropagator::class)) {
+                $propagators[] = $propagator;
+            }
+        }
+        if (count($propagators) === 0) {
+            return null;
+        }
+
+        return $propagators;
+    }
+
+    private function buildPropagator(string $name): ?TextMapPropagatorInterface
+    {
+        try {
+            return Registry::textMapPropagator($name);
+        } catch (\RuntimeException $e) {
+            self::logWarning($e->getMessage());
+        }
+
+        return null;
+    }
+}

src/Instrumentation/PDO/src/PDOInstrumentation.php

@@ -33,6 +33,7 @@ public static function register(): void
             Version::VERSION_1_36_0->url(),
         );
         $pdoTracker = new PDOTracker();
+        $contextPropagator = (new ContextPropagatorFactory())->create();
 
         // Hook for the new PDO::connect static method
         if (method_exists(PDO::class, 'connect')) {
@@ -110,7 +111,7 @@ public static function register(): void
         hook(
             PDO::class,
             'query',
-            pre: static function (PDO $pdo, array $params, string $class, string $function, ?string $filename, ?int $lineno) use ($pdoTracker, $instrumentation) {
+            pre: static function (PDO $pdo, array $params, string $class, string $function, ?string $filename, ?int $lineno) use ($contextPropagator, $pdoTracker, $instrumentation) {
                 /** @psalm-suppress ArgumentTypeCoercion */
                 $builder = self::makeBuilder($instrumentation, 'PDO::query', $function, $class, $filename, $lineno)
                     ->setSpanKind(SpanKind::KIND_CLIENT);
@@ -135,8 +136,15 @@ public static function register(): void
                             case 'postgresql':
                             case 'mysql':
                                 $comments = [];
-                                Globals::propagator()->inject($comments);
-                                $sqlStatement = SqlCommentPropagator::inject($sqlStatement, $comments);
+                                if ($contextPropagator !== null) {
+                                    // Propagator passed by user
+                                    $contextPropagator->inject($comments);
+                                } else {
+                                    // fallback to global propagator if user didn't pass one
+                                    Globals::propagator()->inject($comments);
+                                }
+                                // Inject comments into SQL statement
+                                $sqlStatement = SqlCommentInjector::inject($sqlStatement, $comments);
                                 if (ContextPropagation::isAttributeEnabled()) {
                                     $span->setAttributes([
                                         DbAttributes::DB_QUERY_TEXT => $sqlStatement,
@@ -163,7 +171,7 @@ public static function register(): void
         hook(
             PDO::class,
             'exec',
-            pre: static function (PDO $pdo, array $params, string $class, string $function, ?string $filename, ?int $lineno) use ($pdoTracker, $instrumentation) {
+            pre: static function (PDO $pdo, array $params, string $class, string $function, ?string $filename, ?int $lineno) use ($contextPropagator, $pdoTracker, $instrumentation) {
                 /** @psalm-suppress ArgumentTypeCoercion */
                 $builder = self::makeBuilder($instrumentation, 'PDO::exec', $function, $class, $filename, $lineno)
                     ->setSpanKind(SpanKind::KIND_CLIENT);
@@ -188,8 +196,15 @@ public static function register(): void
                             case 'postgresql':
                             case 'mysql':
                                 $comments = [];
-                                Globals::propagator()->inject($comments);
-                                $sqlStatement = SqlCommentPropagator::inject($sqlStatement, $comments);
+                                if ($contextPropagator !== null) {
+                                    // Propagator passed by user
+                                    $contextPropagator->inject($comments);
+                                } else {
+                                    // fallback to global propagator if user didn't pass one
+                                    Globals::propagator()->inject($comments);
+                                }
+                                // Inject comments into SQL statement
+                                $sqlStatement = SqlCommentInjector::inject($sqlStatement, $comments);
                                 if (ContextPropagation::isAttributeEnabled()) {
                                     $span->setAttributes([
                                         DbAttributes::DB_QUERY_TEXT => $sqlStatement,

src/Instrumentation/PDO/src/SqlCommentPropagator.php → src/Instrumentation/PDO/src/SqlCommentInjector.php

@@ -6,7 +6,7 @@
 
 use OpenTelemetry\SDK\Common\Configuration\Configuration;
 
-class SqlCommentPropagator implements SqlPropagatorInterface
+class SqlCommentInjector implements SqlInjectorInterface
 {
     public static function isPrepend(): bool
     {

src/Instrumentation/PDO/src/SqlPropagatorInterface.php → src/Instrumentation/PDO/src/SqlInjectorInterface.php

@@ -4,7 +4,7 @@
 
 namespace OpenTelemetry\Contrib\Instrumentation\PDO;
 
-interface SqlPropagatorInterface
+interface SqlInjectorInterface
 {
     public static function inject(string $query, array $comments): string;
 }

src/Instrumentation/PDO/tests/Unit/ContextPropagatorFactoryTest.php

@@ -0,0 +1,52 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OpenTelemetry\Tests\Instrumentation\PDO\Unit;
+
+use OpenTelemetry\API\Baggage\Propagation\BaggagePropagator;
+use OpenTelemetry\API\Behavior\Internal\Logging;
+use OpenTelemetry\API\LoggerHolder;
+use OpenTelemetry\API\Trace\Propagation\TraceContextPropagator;
+use OpenTelemetry\Context\Propagation\MultiTextMapPropagator;
+use OpenTelemetry\Contrib\Instrumentation\PDO\ContextPropagatorFactory;
+use OpenTelemetry\SDK\Common\Configuration\KnownValues;
+use PHPUnit\Framework\TestCase;
+
+class ContextPropagatorFactoryTest extends TestCase
+{
+    #[\Override]
+    public function setUp(): void
+    {
+        LoggerHolder::disable();
+        Logging::disable();
+    }
+
+    /**
+     * @psalm-suppress ArgumentTypeCoercion
+     * @dataProvider propagatorsProvider
+     */
+    public function test_create(string $propagators, ?string $expected): void
+    {
+        putenv('OTEL_PHP_INSTRUMENTATION_PDO_CONTEXT_PROPAGATORS=' . $propagators);
+        $propagator = (new ContextPropagatorFactory())->create();
+        if ($expected === null) {
+            $this->assertNull($propagator);
+        } else {
+            $this->assertInstanceOf($expected, $propagator);
+        }
+        putenv('OTEL_PHP_INSTRUMENTATION_PDO_CONTEXT_PROPAGATORS');
+    }
+
+    public static function propagatorsProvider(): array
+    {
+        return [
+            [KnownValues::VALUE_BAGGAGE, BaggagePropagator::class],
+            [KnownValues::VALUE_TRACECONTEXT, TraceContextPropagator::class],
+            [KnownValues::VALUE_NONE, null],
+            [sprintf('%s,%s', KnownValues::VALUE_TRACECONTEXT, KnownValues::VALUE_BAGGAGE), MultiTextMapPropagator::class],
+            ['', null],
+            ['invalid', null],
+        ];
+    }
+}

src/Instrumentation/PDO/tests/Unit/SqlCommentPropagatorTest.php → src/Instrumentation/PDO/tests/Unit/SqlCommentInjectorTest.php

@@ -4,22 +4,22 @@
 
 namespace OpenTelemetry\Tests\Instrumentation\PDO\tests\Unit;
 
-use OpenTelemetry\Contrib\Instrumentation\PDO\SqlCommentPropagator;
+use OpenTelemetry\Contrib\Instrumentation\PDO\SqlCommentInjector;
 use PHPUnit\Framework\TestCase;
 
-class SqlCommentPropagatorTest extends TestCase
+class SqlCommentInjectorTest extends TestCase
 {
     public function testIsPrependReturnsTrue()
     {
         $_SERVER['OTEL_PHP_INSTRUMENTATION_PDO_SQL_COMMENTER_PREPEND'] = true;
-        $result = SqlCommentPropagator::isPrepend();
+        $result = SqlCommentInjector::isPrepend();
         $this->assertTrue($result);
     }
 
     public function testIsPrependReturnsFalse()
     {
         $_SERVER['OTEL_PHP_INSTRUMENTATION_PDO_SQL_COMMENTER_PREPEND'] = false;
-        $result = SqlCommentPropagator::isPrepend();
+        $result = SqlCommentInjector::isPrepend();
         $this->assertFalse($result);
     }
 
@@ -32,7 +32,7 @@ public function testInjectPrepend()
             'key3' => 'value3',
         ];
         $query = 'SELECT 1;';
-        $result = SqlCommentPropagator::inject($query, $comments);
+        $result = SqlCommentInjector::inject($query, $comments);
         $this->assertEquals("/*key1='value1',key2='value2',key3='value3'*/SELECT 1;", $result);
     }
 
@@ -45,7 +45,7 @@ public function testInjectAppend()
             'key3' => 'value3',
         ];
         $query = 'SELECT 1;';
-        $result = SqlCommentPropagator::inject($query, $comments);
+        $result = SqlCommentInjector::inject($query, $comments);
         $this->assertEquals("SELECT 1/*key1='value1',key2='value2',key3='value3'*/;", $result);
     }
 }