spaces.php

aws/Aws/Credentials/EcsCredentialProvider.php

@@ -0,0 +1,86 @@
+<?php
+namespace Aws\Credentials;
+
+use Aws\Exception\CredentialsException;
+use GuzzleHttp\Promise;
+use GuzzleHttp\Psr7\Request;
+use GuzzleHttp\Promise\PromiseInterface;
+use Psr\Http\Message\ResponseInterface;
+
+/**
+ * Credential provider that fetches credentials with GET request.
+ * ECS environment variable is used in constructing request URI.
+ */
+class EcsCredentialProvider
+{
+    const SERVER_URI = 'http://169.254.170.2';
+    const ENV_URI = "AWS_CONTAINER_CREDENTIALS_RELATIVE_URI";
+
+    /** @var callable */
+    private $client;
+
+    /**
+     *  The constructor accepts following options:
+     *  - timeout: (optional) Connection timeout, in seconds, default 1.0
+     *  - client: An EcsClient to make request from
+     *
+     * @param array $config Configuration options
+     */
+    public function __construct(array $config = [])
+    {
+        $this->timeout = isset($config['timeout']) ? $config['timeout'] : 1.0;
+        $this->client = isset($config['client'])
+            ? $config['client']
+            : \Aws\default_http_handler();
+    }
+
+    /**
+     * Load ECS credentials
+     *
+     * @return PromiseInterface
+     */
+    public function __invoke()
+    {
+        $client = $this->client;
+        $request = new Request('GET', self::getEcsUri());
+        return $client(
+            $request,
+            ['timeout' => $this->timeout]
+        )->then(function (ResponseInterface $response) {
+            $result = $this->decodeResult((string) $response->getBody());
+            return new Credentials(
+                $result['AccessKeyId'],
+                $result['SecretAccessKey'],
+                $result['Token'],
+                strtotime($result['Expiration'])
+            );
+        })->otherwise(function ($reason) {
+            $reason = is_array($reason) ? $reason['exception'] : $reason;
+            $msg = $reason->getMessage();
+            throw new CredentialsException(
+                "Error retrieving credential from ECS ($msg)"
+            );
+        });
+    }
+
+    /**
+     * Fetch credential URI from ECS environment variable
+     *
+     * @return string Returns ECS URI
+     */
+    private function getEcsUri()
+    {
+        $creds_uri = getenv(self::ENV_URI);
+        return self::SERVER_URI . $creds_uri;
+    }
+
+    private function decodeResult($response)
+    {
+        $result = json_decode($response, true);
+
+        if (!isset($result['AccessKeyId'])) {
+            throw new CredentialsException('Unexpected ECS credential value');
+        }
+        return $result;
+    }
+}