RFC: Project ID Detection

src/AppEngine/AppIdentity.php

@@ -0,0 +1,59 @@
+<?php
+
+/**
+ * Copyright 2015 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+namespace Google\Cloud\AppEngine;
+
+/*
+ * The AppIdentityS class is automatically defined on App Engine,
+ * so including this dependency is not necessary, and will result in a
+ * PHP fatal error in the App Engine environment.
+ */
+use google\appengine\api\app_identity\AppIdentityService;
+
+/**
+ * A wrapper for the AppEngine AppIdentity service
+ * This class will only work when running on AppEngine, or
+ * if the App Engine SDK is available.
+ *
+ * ```
+ * use Google\Cloud\AppEngine\AppIdentity;
+ *
+ * $appIdentity = new AppIdentity();
+ * $projectId = $identity->getApplicationId();
+ * ```
+ */
+class AppIdentity
+{
+    /**
+     * Get the current application ID from the App Identity Service
+     *
+     * Example:
+     * ```
+     * $projectId = $appIdentity->getApplicationId();
+     * ```
+     *
+     * @return string
+     */
+    public function getApplicationId()
+    {
+        if (!class_exists('google\appengine\api\app_identity\AppIdentityService')) {
+            throw new \Exception('This class must be run in App Engine');
+        }
+
+        return AppIdentityService::getApplicationId();
+    }
+}

src/ClientTrait.php

@@ -30,6 +30,8 @@
  */
 trait ClientTrait
 {
+    use DetectProjectTrait;
+
     /**
      * @var string The project ID created in the Google Developers Console.
      */
@@ -134,9 +136,14 @@ private function getKeyFile(array $config = [])
      * 1. If $config['projectId'] is set, use that.
      * 2. If $config['keyFile'] is set, attempt to retrieve a project ID from
      *    that.
-     * 3. If code is running on compute engine, try to get the project ID from
+     * 3. If the GCLOUD_PROJECT environment variable is set, return this value
+     * 4. If code is running on App Engine, try to get the project ID from the
+     *    App Identity service
+     * 5. If code is running on compute engine, try to get the project ID from
      *    the metadata store
-     * 4. Throw exception.
+     * 6. If the OS-specific gcloud configuration file is set, load it and get
+     *    the project ID from that.
+     * 7. Throw exception.
      *
      * @param  array $config
      * @return string
@@ -157,40 +164,27 @@ private function detectProjectId(array $config)
             return $config['keyFile']['project_id'];
         }
 
-        if ($this->onGce($config['httpHandler'])) {
-            $metadata = $this->getMetaData();
-            $projectId = $metadata->getProjectId();
-            if ($projectId) {
-                return $projectId;
-            }
+        $projectId = $this->projectFromEnvVar();
+        if (!$projectId) {
+            $projectId = $this->projectFromAppEngine();
         }
 
-        throw new GoogleException(
-            'No project ID was provided, ' .
-            'and we were unable to detect a default project ID.'
-        );
-    }
+        if (!$projectId) {
+            $projectId = $this->projectFromGce();
+        }
 
-    /**
-     * Abstract the GCECredentials call so we can mock it in the unit tests!
-     *
-     * @codeCoverageIgnore
-     * @return bool
-     */
-    protected function onGce($httpHandler)
-    {
-        return GCECredentials::onGce($httpHandler);
-    }
+        if (!$projectId) {
+            $projectId = $this->projectFromGcloudConfig();
+        }
 
-    /**
-     * Abstract the Metadata instantiation for unit testing
-     *
-     * @codeCoverageIgnore
-     * @return Metadata
-     */
-    protected function getMetaData()
-    {
-        return new Metadata;
+        if (!$projectId) {
+            throw new GoogleException(
+                'No project ID was provided, ' .
+                'and we were unable to detect a default project ID.'
+            );
+        }
+
+        return $projectId;
     }
 
     /**

src/DetectProjectTrait.php

@@ -0,0 +1,182 @@
+<?php
+/*
+ * Copyright 2015 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+namespace Google\Cloud;
+
+use Google\Auth\Credentials\AppIdentityCredentials;
+use Google\Auth\Credentials\GCECredentials;
+use Google\Auth\CredentialsLoader;
+use Google\Cloud\AppEngine\AppIdentity;
+use Google\Cloud\Compute\Metadata;
+
+/**
+ * DetectProjectTrait contains the behaviour used to locate and find the
+ * default project
+ */
+trait DetectProjectTrait
+{
+    /**
+     * Return a project ID from the GCLOUD_PROJECT environment variable
+     * This is available in App Engine Flexible.
+     *
+     * @return string|null $projectId
+     */
+    protected function projectFromEnvVar()
+    {
+        return getenv($this->getEnvVar());
+    }
+
+    /**
+     * Return a project ID from App Engine.
+     *
+     * @return string|null $projectId
+     */
+    private function projectFromAppEngine()
+    {
+        if ($this->onAppEngine()) {
+            $appIdentity = $this->getAppIdentity();
+            $projectId = $appIdentity->getApplicationId();
+            if ($projectId) {
+                return $projectId;
+            }
+        }
+    }
+
+    /**
+     * Return a project ID from GCE.
+     *
+     * @return string|null $projectId
+     */
+    private function projectFromGce($httpHandler = null)
+    {
+        if ($this->onGce($httpHandler)) {
+            $metadata = $this->getMetaData();
+            $projectId = $metadata->getProjectId();
+            if ($projectId) {
+                return $projectId;
+            }
+        }
+    }
+
+    /**
+     * The gcloud config path is OS dependent:
+     * - windows: %APPDATA%/gcloud/configurations/config_default
+     * - others: $HOME/.config/gcloud/configurations/config_default
+     *
+     * If the file does not exists, this returns null.
+     *
+     * @return string|null $projectId
+     */
+    private function projectFromGcloudConfig()
+    {
+        $path = $this->pathToGcloudConfig();
+        if (!file_exists($path)) {
+            return;
+        }
+        $configDefault = parse_ini_file($path, true);
+        if (isset($configDefault['core']['project'])) {
+            return $configDefault['core']['project'];
+        }
+    }
+
+    /**
+     * Determine the path to the gcloud configuration path
+     *
+     * @codeCoverageIgnore
+     * @return bool
+     */
+    protected function pathToGcloudConfig()
+    {
+        if ($this->onWindows()) {
+            $path = [getenv('APPDATA')];
+        } else {
+            $path = [
+                getenv('HOME'),
+                CredentialsLoader::NON_WINDOWS_WELL_KNOWN_PATH_BASE
+            ];
+        }
+        $path[] = 'gcloud/configurations/config_default';
+        return implode(DIRECTORY_SEPARATOR, $path);
+    }
+
+    /**
+     * Abstract the CredentialsLoader call so we can mock it in the unit tests!
+     *
+     * @codeCoverageIgnore
+     * @return bool
+     */
+    protected function onWindows()
+    {
+        return CredentialsLoader::isOnWindows();
+    }
+
+    /**
+     * Abstract the AppIdentity call so we can mock it in the unit tests!
+     *
+     * @codeCoverageIgnore
+     * @return bool
+     */
+    protected function onAppEngine()
+    {
+        return AppIdentityCredentials::onAppEngine() &&
+            !GCECredentials::onAppEngineFlexible();
+    }
+
+    /**
+     * Abstract the AppIdentity instantiation for unit testing
+     *
+     * @codeCoverageIgnore
+     * @return Metadata
+     */
+    protected function getAppIdentity()
+    {
+        return new AppIdentity;
+    }
+
+    /**
+     * Abstract the GCECredentials call so we can mock it in the unit tests!
+     *
+     * @codeCoverageIgnore
+     * @return bool
+     */
+    protected function onGce($httpHandler)
+    {
+        return GCECredentials::onGce($httpHandler);
+    }
+
+    /**
+     * Abstract the Metadata instantiation for unit testing
+     *
+     * @codeCoverageIgnore
+     * @return Metadata
+     */
+    protected function getMetaData()
+    {
+        return new Metadata;
+    }
+
+    /**
+     * Abstract the Environment Variable name for unit testing
+     *
+     * @codeCoverageIgnore
+     * @return string
+     */
+    protected function getEnvVar()
+    {
+        return 'GCLOUD_PROJECT';
+    }
+}