Add dedicated API for apps' bootstrapping process

Signed-off-by: Christoph Wurst <christoph@winzerhof-wurst.at>

14 files changed, 1046 insertions, 1 deletions

diff --git a/apps/twofactor_backupcodes/lib/AppInfo/Application.php b/apps/twofactor_backupcodes/lib/AppInfo/Application.php
index 4c5d852f956..3cf05073ec8 100644
--- a/apps/twofactor_backupcodes/lib/AppInfo/Application.php
+++ b/apps/twofactor_backupcodes/lib/AppInfo/Application.php
@@ -35,7 +35,6 @@ use OCA\TwoFactorBackupCodes\Listener\RegistryUpdater;
 use OCA\TwoFactorBackupCodes\Notifications\Notifier;
 use OCP\AppFramework\App;
 use OCP\Authentication\TwoFactorAuth\IRegistry;
-use OCP\EventDispatcher\IEventDispatcher;
 use OCP\Notification\IManager;
 use OCP\Util;
 
diff --git a/lib/base.php b/lib/base.php
index 3ac6d978e4e..ab199c09722 100644
--- a/lib/base.php
+++ b/lib/base.php
@@ -644,6 +644,10 @@ class OC {
 			OC\Log\ErrorHandler::register($debug);
 		}
 
+		/** @var \OC\AppFramework\Bootstrap\Coordinator $bootstrapCoordinator */
+		$bootstrapCoordinator = \OC::$server->query(\OC\AppFramework\Bootstrap\Coordinator::class);
+		$bootstrapCoordinator->runRegistration();
+
 		\OC::$server->getEventLogger()->start('init_session', 'Initialize session');
 		OC_App::loadApps(['session']);
 		if (!self::$CLI) {
diff --git a/lib/composer/composer/autoload_classmap.php b/lib/composer/composer/autoload_classmap.php
index 930a14df5d5..09defdc5ae4 100644
--- a/lib/composer/composer/autoload_classmap.php
+++ b/lib/composer/composer/autoload_classmap.php
@@ -23,6 +23,9 @@ return array(
     'OCP\\AppFramework\\ApiController' => $baseDir . '/lib/public/AppFramework/ApiController.php',
     'OCP\\AppFramework\\App' => $baseDir . '/lib/public/AppFramework/App.php',
     'OCP\\AppFramework\\AuthPublicShareController' => $baseDir . '/lib/public/AppFramework/AuthPublicShareController.php',
+    'OCP\\AppFramework\\Bootstrap\\IBootContext' => $baseDir . '/lib/public/AppFramework/Bootstrap/IBootContext.php',
+    'OCP\\AppFramework\\Bootstrap\\IBootstrap' => $baseDir . '/lib/public/AppFramework/Bootstrap/IBootstrap.php',
+    'OCP\\AppFramework\\Bootstrap\\IRegistrationContext' => $baseDir . '/lib/public/AppFramework/Bootstrap/IRegistrationContext.php',
     'OCP\\AppFramework\\Controller' => $baseDir . '/lib/public/AppFramework/Controller.php',
     'OCP\\AppFramework\\Db\\DoesNotExistException' => $baseDir . '/lib/public/AppFramework/Db/DoesNotExistException.php',
     'OCP\\AppFramework\\Db\\Entity' => $baseDir . '/lib/public/AppFramework/Db/Entity.php',
@@ -538,6 +541,9 @@ return array(
     'OC\\AllConfig' => $baseDir . '/lib/private/AllConfig.php',
     'OC\\AppConfig' => $baseDir . '/lib/private/AppConfig.php',
     'OC\\AppFramework\\App' => $baseDir . '/lib/private/AppFramework/App.php',
+    'OC\\AppFramework\\Bootstrap\\BootContext' => $baseDir . '/lib/private/AppFramework/Bootstrap/BootContext.php',
+    'OC\\AppFramework\\Bootstrap\\Coordinator' => $baseDir . '/lib/private/AppFramework/Bootstrap/Coordinator.php',
+    'OC\\AppFramework\\Bootstrap\\RegistrationContext' => $baseDir . '/lib/private/AppFramework/Bootstrap/RegistrationContext.php',
     'OC\\AppFramework\\DependencyInjection\\DIContainer' => $baseDir . '/lib/private/AppFramework/DependencyInjection/DIContainer.php',
     'OC\\AppFramework\\Http' => $baseDir . '/lib/private/AppFramework/Http.php',
     'OC\\AppFramework\\Http\\Dispatcher' => $baseDir . '/lib/private/AppFramework/Http/Dispatcher.php',
diff --git a/lib/composer/composer/autoload_static.php b/lib/composer/composer/autoload_static.php
index 9539dbc1a4b..ef34b902cf4 100644
--- a/lib/composer/composer/autoload_static.php
+++ b/lib/composer/composer/autoload_static.php
@@ -52,6 +52,9 @@ class ComposerStaticInit53792487c5a8370acc0b06b1a864ff4c
         'OCP\\AppFramework\\ApiController' => __DIR__ . '/../../..' . '/lib/public/AppFramework/ApiController.php',
         'OCP\\AppFramework\\App' => __DIR__ . '/../../..' . '/lib/public/AppFramework/App.php',
         'OCP\\AppFramework\\AuthPublicShareController' => __DIR__ . '/../../..' . '/lib/public/AppFramework/AuthPublicShareController.php',
+        'OCP\\AppFramework\\Bootstrap\\IBootContext' => __DIR__ . '/../../..' . '/lib/public/AppFramework/Bootstrap/IBootContext.php',
+        'OCP\\AppFramework\\Bootstrap\\IBootstrap' => __DIR__ . '/../../..' . '/lib/public/AppFramework/Bootstrap/IBootstrap.php',
+        'OCP\\AppFramework\\Bootstrap\\IRegistrationContext' => __DIR__ . '/../../..' . '/lib/public/AppFramework/Bootstrap/IRegistrationContext.php',
         'OCP\\AppFramework\\Controller' => __DIR__ . '/../../..' . '/lib/public/AppFramework/Controller.php',
         'OCP\\AppFramework\\Db\\DoesNotExistException' => __DIR__ . '/../../..' . '/lib/public/AppFramework/Db/DoesNotExistException.php',
         'OCP\\AppFramework\\Db\\Entity' => __DIR__ . '/../../..' . '/lib/public/AppFramework/Db/Entity.php',
@@ -567,6 +570,9 @@ class ComposerStaticInit53792487c5a8370acc0b06b1a864ff4c
         'OC\\AllConfig' => __DIR__ . '/../../..' . '/lib/private/AllConfig.php',
         'OC\\AppConfig' => __DIR__ . '/../../..' . '/lib/private/AppConfig.php',
         'OC\\AppFramework\\App' => __DIR__ . '/../../..' . '/lib/private/AppFramework/App.php',
+        'OC\\AppFramework\\Bootstrap\\BootContext' => __DIR__ . '/../../..' . '/lib/private/AppFramework/Bootstrap/BootContext.php',
+        'OC\\AppFramework\\Bootstrap\\Coordinator' => __DIR__ . '/../../..' . '/lib/private/AppFramework/Bootstrap/Coordinator.php',
+        'OC\\AppFramework\\Bootstrap\\RegistrationContext' => __DIR__ . '/../../..' . '/lib/private/AppFramework/Bootstrap/RegistrationContext.php',
         'OC\\AppFramework\\DependencyInjection\\DIContainer' => __DIR__ . '/../../..' . '/lib/private/AppFramework/DependencyInjection/DIContainer.php',
         'OC\\AppFramework\\Http' => __DIR__ . '/../../..' . '/lib/private/AppFramework/Http.php',
         'OC\\AppFramework\\Http\\Dispatcher' => __DIR__ . '/../../..' . '/lib/private/AppFramework/Http/Dispatcher.php',
diff --git a/lib/private/AppFramework/Bootstrap/BootContext.php b/lib/private/AppFramework/Bootstrap/BootContext.php
new file mode 100644
index 00000000000..3831fe4e396
--- /dev/null
+++ b/lib/private/AppFramework/Bootstrap/BootContext.php
@@ -0,0 +1,48 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * @copyright 2020 Christoph Wurst <christoph@winzerhof-wurst.at>
+ *
+ * @author 2020 Christoph Wurst <christoph@winzerhof-wurst.at>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+namespace OC\AppFramework\Bootstrap;
+
+use OCP\AppFramework\Bootstrap\IBootContext;
+use OCP\AppFramework\IAppContainer;
+use OCP\IServerContainer;
+
+class BootContext implements IBootContext {
+
+	/** @var IAppContainer */
+	private $appContainer;
+
+	public function __construct(IAppContainer $appContainer) {
+		$this->appContainer = $appContainer;
+	}
+
+	public function getAppContainer(): IAppContainer {
+		return $this->appContainer;
+	}
+
+	public function getServerContainer(): IServerContainer {
+		return $this->appContainer->getServer();
+	}
+}
diff --git a/lib/private/AppFramework/Bootstrap/Coordinator.php b/lib/private/AppFramework/Bootstrap/Coordinator.php
new file mode 100644
index 00000000000..e713ad7ce91
--- /dev/null
+++ b/lib/private/AppFramework/Bootstrap/Coordinator.php
@@ -0,0 +1,130 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * @copyright 2020 Christoph Wurst <christoph@winzerhof-wurst.at>
+ *
+ * @author 2020 Christoph Wurst <christoph@winzerhof-wurst.at>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+namespace OC\AppFramework\Bootstrap;
+
+use OC_App;
+use OCP\AppFramework\App;
+use OCP\AppFramework\Bootstrap\IBootstrap;
+use OCP\AppFramework\QueryException;
+use OCP\EventDispatcher\IEventDispatcher;
+use OCP\ILogger;
+use OCP\IServerContainer;
+use function class_exists;
+use function class_implements;
+use function in_array;
+
+class Coordinator {
+
+	/** @var IServerContainer */
+	private $serverContainer;
+
+	/** @var IEventDispatcher */
+	private $eventDispatcher;
+
+	/** @var ILogger */
+	private $logger;
+
+	public function __construct(IServerContainer $container,
+								IEventDispatcher $eventListener,
+								ILogger $logger) {
+		$this->serverContainer = $container;
+		$this->eventDispatcher = $eventListener;
+		$this->logger = $logger;
+	}
+
+	public function runRegistration(): void {
+		$context = new RegistrationContext($this->logger);
+		$apps = [];
+		foreach (OC_App::getEnabledApps() as $appId) {
+			/*
+			 * First, we have to enable the app's autoloader
+			 *
+			 * @todo use $this->appManager->getAppPath($appId) here
+			 */
+			$path = OC_App::getAppPath($appId);
+			if ($path === false) {
+				// Ignore
+				continue;
+			}
+			OC_App::registerAutoloading($appId, $path);
+
+			/*
+			 * Next we check if there is an application class and it implements
+			 * the \OCP\AppFramework\Bootstrap\IBootstrap interface
+			 */
+			$appNameSpace = App::buildAppNamespace($appId);
+			$applicationClassName = $appNameSpace . '\\AppInfo\\Application';
+			if (class_exists($applicationClassName) && in_array(IBootstrap::class, class_implements($applicationClassName), true)) {
+				try {
+					/** @var IBootstrap|App $application */
+					$apps[$appId] = $application = $this->serverContainer->query($applicationClassName);
+					$application->register($context->for($appId));
+				} catch (QueryException $e) {
+					// Weird, but ok
+				}
+			}
+		}
+
+		/**
+		 * Now that all register methods have been called, we can delegate the registrations
+		 * to the actual services
+		 */
+		$context->delegateCapabilityRegistrations($apps);
+		$context->delegateEventListenerRegistrations($this->eventDispatcher);
+		$context->delegateContainerRegistrations($apps);
+		$context->delegateMiddlewareRegistrations($apps);
+	}
+
+	public function bootApp(string $appId): void {
+		$appNameSpace = App::buildAppNamespace($appId);
+		$applicationClassName = $appNameSpace . '\\AppInfo\\Application';
+		if (!class_exists($applicationClassName)) {
+			// Nothing to boot
+			return;
+		}
+
+		/*
+		 * Now it is time to fetch an instance of the App class. For classes
+		 * that implement \OCP\AppFramework\Bootstrap\IBootstrap this means
+		 * the instance was already created for register, but any other
+		 * (legacy) code will now do their magic via the constructor.
+		 */
+		try {
+			/** @var App $application */
+			$application = $this->serverContainer->query($applicationClassName);
+			if ($application instanceof IBootstrap) {
+				/** @var BootContext $context */
+				$context = new BootContext($application->getContainer());
+				$application->boot($context);
+			}
+		} catch (QueryException $e) {
+			$this->logger->logException($e, [
+				'message' => "Could not boot $appId" . $e->getMessage(),
+			]);
+			return;
+		}
+	}
+}
diff --git a/lib/private/AppFramework/Bootstrap/RegistrationContext.php b/lib/private/AppFramework/Bootstrap/RegistrationContext.php
new file mode 100644
index 00000000000..c7b2290e6b8
--- /dev/null
+++ b/lib/private/AppFramework/Bootstrap/RegistrationContext.php
@@ -0,0 +1,295 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * @copyright 2020 Christoph Wurst <christoph@winzerhof-wurst.at>
+ *
+ * @author 2020 Christoph Wurst <christoph@winzerhof-wurst.at>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+namespace OC\AppFramework\Bootstrap;
+
+use Closure;
+use OCP\AppFramework\App;
+use OCP\AppFramework\Bootstrap\IRegistrationContext;
+use OCP\EventDispatcher\IEventDispatcher;
+use OCP\ILogger;
+use Throwable;
+
+class RegistrationContext {
+
+	/** @var array[] */
+	private $capabilities = [];
+
+	/** @var array[] */
+	private $services = [];
+
+	/** @var array[] */
+	private $aliases = [];
+
+	/** @var array[] */
+	private $parameters = [];
+
+	/** @var array[] */
+	private $eventListeners = [];
+
+	/** @var array[] */
+	private $middlewares = [];
+
+	/** @var ILogger */
+	private $logger;
+
+	public function __construct(ILogger $logger) {
+		$this->logger = $logger;
+	}
+
+	public function for(string $appId): IRegistrationContext {
+		return new class($appId, $this) implements IRegistrationContext {
+			/** @var string */
+			private $appId;
+
+			/** @var RegistrationContext */
+			private $context;
+
+			public function __construct(string $appId, RegistrationContext $context) {
+				$this->appId = $appId;
+				$this->context = $context;
+			}
+
+			public function registerCapability(string $capability): void {
+				$this->context->registerCapability(
+					$this->appId,
+					$capability
+				);
+			}
+
+			public function registerService(string $name, callable $factory, bool $shared = true): void {
+				$this->context->registerService(
+					$this->appId,
+					$name,
+					$factory,
+					$shared
+				);
+			}
+
+			public function registerServiceAlias(string $alias, string $target): void {
+				$this->context->registerServiceAlias(
+					$this->appId,
+					$alias,
+					$target
+				);
+			}
+
+			public function registerParameter(string $name, $value): void {
+				$this->context->registerParameter(
+					$this->appId,
+					$name,
+					$value
+				);
+			}
+
+			public function registerEventListener(string $event, string $listener, int $priority = 0): void {
+				$this->context->registerEventListener(
+					$this->appId,
+					$event,
+					$listener,
+					$priority
+				);
+			}
+
+			public function registerMiddleware(string $class): void {
+				$this->context->registerMiddleware(
+					$this->appId,
+					$class
+				);
+			}
+		};
+	}
+
+	public function registerCapability(string $appId, string $capability): void {
+		$this->capabilities[] = [
+			'appId' => $appId,
+			'capability' => $capability
+		];
+	}
+
+	public function registerService(string $appId, string $name, callable $factory, bool $shared = true): void {
+		$this->services[] = [
+			"appId" => $appId,
+			"name" => $name,
+			"factory" => $factory,
+			"sharred" => $shared,
+		];
+	}
+
+	public function registerServiceAlias(string $appId, string $alias, string $target): void {
+		$this->aliases[] = [
+			"appId" => $appId,
+			"alias" => $alias,
+			"target" => $target,
+		];
+	}
+
+	public function registerParameter(string $appId, string $name, $value): void {
+		$this->parameters[] = [
+			"appId" => $appId,
+			"name" => $name,
+			"value" => $value,
+		];
+	}
+
+	public function registerEventListener(string $appId, string $event, string $listener, int $priority = 0): void {
+		$this->eventListeners[] = [
+			"appId" => $appId,
+			"event" => $event,
+			"listener" => $listener,
+			"priority" => $priority,
+		];
+	}
+
+	public function registerMiddleware(string $appId, string $class): void {
+		$this->middlewares[] = [
+			"appId" => $appId,
+			"class" => $class,
+		];
+	}
+
+	/**
+	 * @param App[] $apps
+	 */
+	public function delegateCapabilityRegistrations(array $apps): void {
+		foreach ($this->capabilities as $registration) {
+			try {
+				$apps[$registration['appId']]
+					->getContainer()
+					->registerCapability($registration['capability']);
+			} catch (Throwable $e) {
+				$appId = $registration['appId'];
+				$this->logger->logException($e, [
+					'message' => "Error during capability registration of $appId: " . $e->getMessage(),
+					'level' => ILogger::ERROR,
+				]);
+			}
+		}
+	}
+
+	public function delegateEventListenerRegistrations(IEventDispatcher $eventDispatcher): void {
+		foreach ($this->eventListeners as $registration) {
+			try {
+				if (isset($registration['priority'])) {
+					$eventDispatcher->addServiceListener(
+						$registration['event'],
+						$registration['listener'],
+						$registration['priority']
+					);
+				} else {
+					$eventDispatcher->addListener(
+						$registration['event'],
+						$registration['listener']
+					);
+				}
+			} catch (Throwable $e) {
+				$appId = $registration['appId'];
+				$this->logger->logException($e, [
+					'message' => "Error during event listener registration of $appId: " . $e->getMessage(),
+					'level' => ILogger::ERROR,
+				]);
+			}
+		}
+	}
+
+	/**
+	 * @param App[] $apps
+	 */
+	public function delegateContainerRegistrations(array $apps): void {
+		foreach ($this->services as $registration) {
+			try {
+				/**
+				 * Register the service and convert the callable into a \Closure if necessary
+				 */
+				$apps[$registration['appId']]
+					->getContainer()
+					->registerService(
+						$registration['name'],
+						Closure::fromCallable($registration['factory']),
+						$registration['shared'] ?? true
+					);
+			} catch (Throwable $e) {
+				$appId = $registration['appId'];
+				$this->logger->logException($e, [
+					'message' => "Error during service registration of $appId: " . $e->getMessage(),
+					'level' => ILogger::ERROR,
+				]);
+			}
+		}
+
+		foreach ($this->aliases as $registration) {
+			try {
+				$apps[$registration['appId']]
+					->getContainer()
+					->registerAlias(
+						$registration['alias'],
+						$registration['target']
+					);
+			} catch (Throwable $e) {
+				$appId = $registration['appId'];
+				$this->logger->logException($e, [
+					'message' => "Error during service alias registration of $appId: " . $e->getMessage(),
+					'level' => ILogger::ERROR,
+				]);
+			}
+		}
+
+		foreach ($this->parameters as $registration) {
+			try {
+				$apps[$registration['appId']]
+					->getContainer()
+					->registerParameter(
+						$registration['name'],
+						$registration['value']
+					);
+			} catch (Throwable $e) {
+				$appId = $registration['appId'];
+				$this->logger->logException($e, [
+					'message' => "Error during service alias registration of $appId: " . $e->getMessage(),
+					'level' => ILogger::ERROR,
+				]);
+			}
+		}
+	}
+
+	/**
+	 * @param App[] $apps
+	 */
+	public function delegateMiddlewareRegistrations(array $apps): void {
+		foreach ($this->middlewares as $middleware) {
+			try {
+				$apps[$middleware['appId']]
+					->getContainer()
+					->registerMiddleWare($middleware['class']);
+			} catch (Throwable $e) {
+				$appId = $middleware['appId'];
+				$this->logger->logException($e, [
+					'message' => "Error during capability registration of $appId: " . $e->getMessage(),
+					'level' => ILogger::ERROR,
+				]);
+			}
+		}
+	}
+}
diff --git a/lib/private/legacy/OC_App.php b/lib/private/legacy/OC_App.php
index dfeac41497f..a3c429c9ce4 100644
--- a/lib/private/legacy/OC_App.php
+++ b/lib/private/legacy/OC_App.php
@@ -149,6 +149,9 @@ class OC_App {
 		// in case someone calls loadApp() directly
 		self::registerAutoloading($app, $appPath);
 
+		/** @var \OC\AppFramework\Bootstrap\Coordinator $coordinator */
+		$coordinator = \OC::$server->query(\OC\AppFramework\Bootstrap\Coordinator::class);
+		$coordinator->bootApp($app);
 		if (is_file($appPath . '/appinfo/app.php')) {
 			\OC::$server->getEventLogger()->start('load_app_' . $app, 'Load app: ' . $app);
 			try {
diff --git a/lib/public/AppFramework/Bootstrap/IBootContext.php b/lib/public/AppFramework/Bootstrap/IBootContext.php
new file mode 100644
index 00000000000..6ceec5d2fcb
--- /dev/null
+++ b/lib/public/AppFramework/Bootstrap/IBootContext.php
@@ -0,0 +1,55 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * @copyright 2020 Christoph Wurst <christoph@winzerhof-wurst.at>
+ *
+ * @author 2020 Christoph Wurst <christoph@winzerhof-wurst.at>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+namespace OCP\AppFramework\Bootstrap;
+
+use OCP\AppFramework\IAppContainer;
+use OCP\IServerContainer;
+
+/**
+ * @since 20.0.0
+ */
+interface IBootContext {
+
+	/**
+	 * Get hold of the app's container
+	 *
+	 * Useful to register and query app-specific services
+	 *
+	 * @return IAppContainer
+	 * @since 20.0.0
+	 */
+	public function getAppContainer(): IAppContainer;
+
+	/**
+	 * Get hold of the server DI container
+	 *
+	 * Useful to register and query system-wide services
+	 *
+	 * @return IServerContainer
+	 * @since 20.0.0
+	 */
+	public function getServerContainer(): IServerContainer;
+}
diff --git a/lib/public/AppFramework/Bootstrap/IBootstrap.php b/lib/public/AppFramework/Bootstrap/IBootstrap.php
new file mode 100644
index 00000000000..581c7d6636a
--- /dev/null
+++ b/lib/public/AppFramework/Bootstrap/IBootstrap.php
@@ -0,0 +1,46 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * @copyright 2020 Christoph Wurst <christoph@winzerhof-wurst.at>
+ *
+ * @author 2020 Christoph Wurst <christoph@winzerhof-wurst.at>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+namespace OCP\AppFramework\Bootstrap;
+
+/**
+ * @since 20.0.0
+ */
+interface IBootstrap {
+
+	/**
+	 * @param IRegistrationContext $context
+	 *
+	 * @since 20.0.0
+	 */
+	public function register(IRegistrationContext $context): void;
+
+	/**
+	 * @param IBootContext $context
+	 *
+	 * @since 20.0.0
+	 */
+	public function boot(IBootContext $context): void;
+}
diff --git a/lib/public/AppFramework/Bootstrap/IRegistrationContext.php b/lib/public/AppFramework/Bootstrap/IRegistrationContext.php
new file mode 100644
index 00000000000..589b5def5a8
--- /dev/null
+++ b/lib/public/AppFramework/Bootstrap/IRegistrationContext.php
@@ -0,0 +1,108 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * @copyright 2020 Christoph Wurst <christoph@winzerhof-wurst.at>
+ *
+ * @author 2020 Christoph Wurst <christoph@winzerhof-wurst.at>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+namespace OCP\AppFramework\Bootstrap;
+
+use OCP\AppFramework\IAppContainer;
+use OCP\EventDispatcher\IEventDispatcher;
+use OCP\IContainer;
+
+/**
+ * The context object passed to IBootstrap::register
+ *
+ * @since 20.0.0
+ * @see IBootstrap::register()
+ */
+interface IRegistrationContext {
+
+	/**
+	 * @param string $capability
+	 * @see IAppContainer::registerCapability
+	 *
+	 * @since 20.0.0
+	 */
+	public function registerCapability(string $capability): void;
+
+	/**
+	 * Register a service
+	 *
+	 * @param string $name
+	 * @param callable $factory
+	 * @param bool $shared
+	 *
+	 * @return void
+	 * @see IContainer::registerService()
+	 *
+	 * @since 20.0.0
+	 */
+	public function registerService(string $name, callable $factory, bool $shared = true): void;
+
+	/**
+	 * @param string $alias
+	 * @param string $target
+	 *
+	 * @return void
+	 * @see IContainer::registerAlias()
+	 *
+	 * @since 20.0.0
+	 */
+	public function registerServiceAlias(string $alias, string $target): void;
+
+	/**
+	 * @param string $name
+	 * @param mixed $value
+	 *
+	 * @return void
+	 * @see IContainer::registerParameter()
+	 *
+	 * @since 20.0.0
+	 */
+	public function registerParameter(string $name, $value): void;
+
+	/**
+	 * Register a service listener
+	 *
+	 * This is equivalent to calling IEventDispatcher::addServiceListener
+	 *
+	 * @param string $event preferably the fully-qualified class name of the Event sub class to listen for
+	 * @param string $listener fully qualified class name (or ::class notation) of a \OCP\EventDispatcher\IEventListener that can be built by the DI container
+	 * @param int $priority
+	 *
+	 * @see IEventDispatcher::addServiceListener()
+	 *
+	 * @since 20.0.0
+	 */
+	public function registerEventListener(string $event, string $listener, int $priority = 0): void;
+
+	/**
+	 * @param string $class
+	 *
+	 * @return void
+	 * @see IAppContainer::registerMiddleWare()
+	 *
+	 * @since 20.0.0
+	 */
+	public function registerMiddleware(string $class): void;
+}
diff --git a/tests/lib/AppFramework/Bootstrap/BootContextTest.php b/tests/lib/AppFramework/Bootstrap/BootContextTest.php
new file mode 100644
index 00000000000..219c6d7e782
--- /dev/null
+++ b/tests/lib/AppFramework/Bootstrap/BootContextTest.php
@@ -0,0 +1,67 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * @copyright 2020 Christoph Wurst <christoph@winzerhof-wurst.at>
+ *
+ * @author 2020 Christoph Wurst <christoph@winzerhof-wurst.at>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+namespace lib\AppFramework\Bootstrap;
+
+use OC\AppFramework\Bootstrap\BootContext;
+use OCP\AppFramework\IAppContainer;
+use OCP\IServerContainer;
+use PHPUnit\Framework\MockObject\MockObject;
+use Test\TestCase;
+
+class BootContextTest extends TestCase {
+
+	/** @var IAppContainer|MockObject */
+	private $appContainer;
+
+	/** @var BootContext */
+	private $context;
+
+	protected function setUp(): void {
+		parent::setUp();
+
+		$this->appContainer = $this->createMock(IAppContainer::class);
+
+		$this->context = new BootContext(
+			$this->appContainer
+		);
+	}
+
+	public function testGetAppContainer(): void {
+		$container = $this->context->getAppContainer();
+
+		$this->assertSame($this->appContainer, $container);
+	}
+
+	public function testGetServerContainer(): void {
+		$serverContainer = $this->createMock(IServerContainer::class);
+		$this->appContainer->method('getServer')
+			->willReturn($serverContainer);
+
+		$container = $this->context->getServerContainer();
+
+		$this->assertSame($serverContainer, $container);
+	}
+}
diff --git a/tests/lib/AppFramework/Bootstrap/CoordinatorTest.php b/tests/lib/AppFramework/Bootstrap/CoordinatorTest.php
new file mode 100644
index 00000000000..114872ed54d
--- /dev/null
+++ b/tests/lib/AppFramework/Bootstrap/CoordinatorTest.php
@@ -0,0 +1,116 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * @copyright 2020 Christoph Wurst <christoph@winzerhof-wurst.at>
+ *
+ * @author 2020 Christoph Wurst <christoph@winzerhof-wurst.at>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+namespace lib\AppFramework\Bootstrap;
+
+use OC\AppFramework\Bootstrap\Coordinator;
+use OCP\App\IAppManager;
+use OCP\AppFramework\App;
+use OCP\AppFramework\Bootstrap\IBootContext;
+use OCP\AppFramework\Bootstrap\IBootstrap;
+use OCP\AppFramework\Bootstrap\IRegistrationContext;
+use OCP\AppFramework\QueryException;
+use OCP\EventDispatcher\IEventDispatcher;
+use OCP\ILogger;
+use OCP\IServerContainer;
+use PHPUnit\Framework\MockObject\MockObject;
+use Test\TestCase;
+
+class CoordinatorTest extends TestCase {
+
+	/** @var IAppManager|MockObject */
+	private $appManager;
+
+	/** @var IServerContainer|MockObject */
+	private $serverContainer;
+
+	/** @var IEventDispatcher|MockObject */
+	private $eventDispatcher;
+
+	/** @var ILogger|MockObject */
+	private $logger;
+
+	/** @var Coordinator */
+	private $coordinator;
+
+	protected function setUp(): void {
+		parent::setUp();
+
+		$this->appManager = $this->createMock(IAppManager::class);
+		$this->serverContainer = $this->createMock(IServerContainer::class);
+		$this->eventDispatcher = $this->createMock(IEventDispatcher::class);
+		$this->logger = $this->createMock(ILogger::class);
+
+		$this->coordinator = new Coordinator(
+			$this->serverContainer,
+			$this->eventDispatcher,
+			$this->logger
+		);
+	}
+
+	public function testBootAppNotLoadable(): void {
+		$appId = 'settings';
+		$this->serverContainer->expects($this->once())
+			->method('query')
+			->with(\OCA\Settings\AppInfo\Application::class)
+			->willThrowException(new QueryException(""));
+		$this->logger->expects($this->once())
+			->method('logException');
+
+		$this->coordinator->bootApp($appId);
+	}
+
+	public function testBootAppNotBootable(): void {
+		$appId = 'settings';
+		$mockApp = $this->createMock(\OCA\Settings\AppInfo\Application::class);
+		$this->serverContainer->expects($this->once())
+			->method('query')
+			->with(\OCA\Settings\AppInfo\Application::class)
+			->willReturn($mockApp);
+
+		$this->coordinator->bootApp($appId);
+	}
+
+	public function testBootApp(): void {
+		$appId = 'settings';
+		$mockApp = new class extends App implements IBootstrap {
+			public function __construct() {
+				parent::__construct('test', []);
+			}
+
+			public function register(IRegistrationContext $context): void {
+			}
+
+			public function boot(IBootContext $context): void {
+			}
+		};
+		$this->serverContainer->expects($this->once())
+			->method('query')
+			->with(\OCA\Settings\AppInfo\Application::class)
+			->willReturn($mockApp);
+
+		$this->coordinator->bootApp($appId);
+	}
+}
diff --git a/tests/lib/AppFramework/Bootstrap/RegistrationContextTest.php b/tests/lib/AppFramework/Bootstrap/RegistrationContextTest.php
new file mode 100644
index 00000000000..8441b6e983d
--- /dev/null
+++ b/tests/lib/AppFramework/Bootstrap/RegistrationContextTest.php
@@ -0,0 +1,162 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * @copyright 2020 Christoph Wurst <christoph@winzerhof-wurst.at>
+ *
+ * @author 2020 Christoph Wurst <christoph@winzerhof-wurst.at>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+namespace lib\AppFramework\Bootstrap;
+
+use OC\AppFramework\Bootstrap\RegistrationContext;
+use OCP\AppFramework\App;
+use OCP\AppFramework\IAppContainer;
+use OCP\EventDispatcher\IEventDispatcher;
+use OCP\ILogger;
+use PHPUnit\Framework\MockObject\MockObject;
+use Test\TestCase;
+
+class RegistrationContextTest extends TestCase {
+
+	/** @var ILogger|MockObject */
+	private $logger;
+
+	/** @var RegistrationContext */
+	private $context;
+
+	protected function setUp(): void {
+		parent::setUp();
+
+		$this->logger = $this->createMock(ILogger::class);
+
+		$this->context = new RegistrationContext(
+			$this->logger
+		);
+	}
+
+	public function testRegisterCapability(): void {
+		$app = $this->createMock(App::class);
+		$name = 'abc';
+		$container = $this->createMock(IAppContainer::class);
+		$app->method('getContainer')
+			->willReturn($container);
+		$container->expects($this->once())
+			->method('registerCapability')
+			->with($name);
+		$this->logger->expects($this->never())
+			->method('logException');
+
+		$this->context->for('myapp')->registerCapability($name);
+		$this->context->delegateCapabilityRegistrations([
+			'myapp' => $app,
+		]);
+	}
+
+	public function testRegisterEventListener(): void {
+		$event = 'abc';
+		$service = 'def';
+		$dispatcher = $this->createMock(IEventDispatcher::class);
+		$dispatcher->expects($this->once())
+			->method('addServiceListener')
+			->with($event, $service, 0);
+		$this->logger->expects($this->never())
+			->method('logException');
+
+		$this->context->for('myapp')->registerEventListener($event, $service);
+		$this->context->delegateEventListenerRegistrations($dispatcher);
+	}
+
+	public function testRegisterService(): void {
+		$app = $this->createMock(App::class);
+		$service = 'abc';
+		$factory = function () {
+			return 'def';
+		};
+		$container = $this->createMock(IAppContainer::class);
+		$app->method('getContainer')
+			->willReturn($container);
+		$container->expects($this->once())
+			->method('registerService')
+			->with($service, $factory, true);
+		$this->logger->expects($this->never())
+			->method('logException');
+
+		$this->context->for('myapp')->registerService($service, $factory);
+		$this->context->delegateContainerRegistrations([
+			'myapp' => $app,
+		]);
+	}
+
+	public function testRegisterServiceAlias(): void {
+		$app = $this->createMock(App::class);
+		$alias = 'abc';
+		$target = 'def';
+		$container = $this->createMock(IAppContainer::class);
+		$app->method('getContainer')
+			->willReturn($container);
+		$container->expects($this->once())
+			->method('registerAlias')
+			->with($alias, $target);
+		$this->logger->expects($this->never())
+			->method('logException');
+
+		$this->context->for('myapp')->registerServiceAlias($alias, $target);
+		$this->context->delegateContainerRegistrations([
+			'myapp' => $app,
+		]);
+	}
+
+	public function testRegisterParameter(): void {
+		$app = $this->createMock(App::class);
+		$name = 'abc';
+		$value = 'def';
+		$container = $this->createMock(IAppContainer::class);
+		$app->method('getContainer')
+			->willReturn($container);
+		$container->expects($this->once())
+			->method('registerParameter')
+			->with($name, $value);
+		$this->logger->expects($this->never())
+			->method('logException');
+
+		$this->context->for('myapp')->registerParameter($name, $value);
+		$this->context->delegateContainerRegistrations([
+			'myapp' => $app,
+		]);
+	}
+
+	public function testRegisterMiddleware(): void {
+		$app = $this->createMock(App::class);
+		$name = 'abc';
+		$container = $this->createMock(IAppContainer::class);
+		$app->method('getContainer')
+			->willReturn($container);
+		$container->expects($this->once())
+			->method('registerMiddleware')
+			->with($name);
+		$this->logger->expects($this->never())
+			->method('logException');
+
+		$this->context->for('myapp')->registerMiddleware($name);
+		$this->context->delegateMiddlewareRegistrations([
+			'myapp' => $app,
+		]);
+	}
+}