feat: set tc-php/<version> User-Agent header for Docker API requests

composer.json

@@ -16,7 +16,8 @@
     "require": {
         "ext-curl": "*",
         "php": ">= 8.1",
-        "beluga-php/docker-php": "^1.45"
+        "beluga-php/docker-php": "^1.45",
+        "php-http/client-common": "^2.7"
     },
     "require-dev": {
         "ext-pdo": "*",

src/ContainerClient/DockerContainerClient.php

@@ -4,7 +4,11 @@
 
 namespace Testcontainers\ContainerClient;
 
+use Composer\InstalledVersions;
 use Docker\Docker as DockerClient;
+use Docker\DockerClientFactory;
+use Http\Client\Common\Plugin\HeaderDefaultsPlugin;
+use Http\Client\Common\PluginClient;
 
 class DockerContainerClient
 {
@@ -26,14 +30,30 @@ private function __construct()
     public static function getDockerClient(): DockerClient
     {
         if (self::$dockerClient === null) {
-            self::$dockerClient = DockerClient::create();
+            try {
+                $version = InstalledVersions::getPrettyVersion('testcontainers/testcontainers') ?? 'unknown';
+            } catch (\OutOfBoundsException) {
+                $version = 'unknown';
+            }
+
+            $version = str_replace('+no-version-set', '', $version);
+
+            $baseHttpClient = DockerClientFactory::createFromEnv();
+
+            $httpClient = new PluginClient(
+                $baseHttpClient,
+                [new HeaderDefaultsPlugin(['User-Agent' => 'tc-php/' . $version])]
+            );
+
+            self::$dockerClient = DockerClient::create($httpClient);
         }
 
         return self::$dockerClient;
     }
 
     /**
      * Injects a DockerClient instance for testing or special use cases.
+     * Note: clients injected via this method will not have the tc-php User-Agent header applied automatically.
      *
      * @param DockerClient $client The DockerClient instance to set.
      */