From 63f34d34b14af9e114e20db3b7698f7746d9409c Mon Sep 17 00:00:00 2001
From: Bertrand Dunogier <bertrand.dunogier@ez.no>
Date: Wed, 3 Nov 2021 17:47:51 +0100
Subject: [PATCH 1/3] Implemented compiled schema synchronization

---
 composer.json                                 |   1 +
 src/Command/PublishSchemaCommand.php          |  60 ++++++++++
 .../EzSystemsEzPlatformGraphQLExtension.php   |   1 +
 .../config/services/schema_sync.yaml          |  39 +++++++
 src/Schema/Sync/AddTypesSolutions.php         |  88 +++++++++++++++
 src/Schema/Sync/LocalFolderSharedSchema.php   |  68 ++++++++++++
 src/Schema/Sync/RedisTimestampHandler.php     |  38 +++++++
 src/Schema/Sync/SharedSchema.php              |  27 +++++
 src/Schema/Sync/TimestampHandler.php          |  14 +++
 src/Schema/Sync/UpdateSchemaIfNeeded.php      | 103 ++++++++++++++++++
 10 files changed, 439 insertions(+)
 create mode 100644 src/Command/PublishSchemaCommand.php
 create mode 100644 src/Resources/config/services/schema_sync.yaml
 create mode 100644 src/Schema/Sync/AddTypesSolutions.php
 create mode 100644 src/Schema/Sync/LocalFolderSharedSchema.php
 create mode 100644 src/Schema/Sync/RedisTimestampHandler.php
 create mode 100644 src/Schema/Sync/SharedSchema.php
 create mode 100644 src/Schema/Sync/TimestampHandler.php
 create mode 100644 src/Schema/Sync/UpdateSchemaIfNeeded.php

diff --git a/composer.json b/composer.json
index b0e7e782..82ebe38e 100644
--- a/composer.json
+++ b/composer.json
@@ -19,6 +19,7 @@
         "ezsystems/ezplatform-admin-ui": "^2.0@dev",
         "ezsystems/ezplatform-rest": "^1.2@dev",
         "ezsystems/ezplatform-richtext": "^2.0@dev",
+        "ext-redis": "*",
         "lexik/jwt-authentication-bundle": "^2.8",
         "overblog/graphql-bundle": "^0.12",
         "erusev/parsedown": "^1.7",
diff --git a/src/Command/PublishSchemaCommand.php b/src/Command/PublishSchemaCommand.php
new file mode 100644
index 00000000..60f197c4
--- /dev/null
+++ b/src/Command/PublishSchemaCommand.php
@@ -0,0 +1,60 @@
+<?php
+/**
+ * @copyright Copyright (C) eZ Systems AS. All rights reserved.
+ * @license For full copyright and license information view LICENSE file distributed with this source code.
+ */
+
+namespace EzSystems\EzPlatformGraphQL\Command;
+
+use EzSystems\EzPlatformGraphQL\Schema\Sync\SharedSchema;
+use Redis;
+use Symfony\Component\Console\Command\Command;
+use Symfony\Component\Console\Input\InputInterface;
+use Symfony\Component\Console\Output\OutputInterface;
+use Symfony\Component\Console\Style\SymfonyStyle;
+use Symfony\Component\Finder\Finder;
+
+class PublishSchemaCommand extends Command
+{
+    /**
+     * @var string
+     */
+    private $definitionsDirectory;
+
+    /**
+     * @var \EzSystems\EzPlatformGraphQL\Schema\Sync\SharedSchema
+     */
+    private $sharedSchema;
+
+    public function __construct(SharedSchema $sharedSchema, string $definitionsDirectory, string $name = null)
+    {
+        parent::__construct($name);
+        $this->definitionsDirectory = $definitionsDirectory;
+        $this->sharedSchema = $sharedSchema;
+    }
+
+    public function configure()
+    {
+        $this->setName('ibexa:graphql:publish-schema');
+    }
+
+    protected function execute(InputInterface $input, OutputInterface $output)
+    {
+        $io = new SymfonyStyle($input, $output);
+
+        foreach ((new Finder())->files()->in($this->definitionsDirectory) as $file) {
+            $this->sharedSchema->addFile($file->getBasename(), $file->getContents());
+        }
+
+        try {
+            $this->sharedSchema->publish(
+                filemtime("$this->definitionsDirectory/__classes.map")
+            );
+        } catch (\Exception $e) {
+            $io->error($e->getMessage());
+            return self::FAILURE;
+        }
+
+        return self::SUCCESS;
+    }
+}
diff --git a/src/DependencyInjection/EzSystemsEzPlatformGraphQLExtension.php b/src/DependencyInjection/EzSystemsEzPlatformGraphQLExtension.php
index 6076f2c9..12603c1e 100644
--- a/src/DependencyInjection/EzSystemsEzPlatformGraphQLExtension.php
+++ b/src/DependencyInjection/EzSystemsEzPlatformGraphQLExtension.php
@@ -39,6 +39,7 @@ public function load(array $configs, ContainerBuilder $container)
         $loader->load('services/mutations.yaml');
         $loader->load('services/resolvers.yaml');
         $loader->load('services/schema.yaml');
+        $loader->load('services/schema_sync.yaml');
         $loader->load('services/services.yaml');
         $loader->load('default_settings.yaml');
     }
diff --git a/src/Resources/config/services/schema_sync.yaml b/src/Resources/config/services/schema_sync.yaml
new file mode 100644
index 00000000..eefbf2d1
--- /dev/null
+++ b/src/Resources/config/services/schema_sync.yaml
@@ -0,0 +1,39 @@
+parameters:
+    ibexa_graphql.definitions_directory: '%kernel.cache_dir%/overblog/graphql-bundle/__definitions__'
+    ibexa_graphql.sync.shared_directory: '/tmp/graphql-schema'
+
+services:
+    _defaults:
+        autoconfigure: true
+        autowire: true
+        public: false
+
+    EzSystems\EzPlatformGraphQL\Command\PublishSchemaCommand:
+        arguments:
+            $definitionsDirectory: '%ibexa_graphql.definitions_directory%'
+
+    EzSystems\EzPlatformGraphQL\Schema\Sync\LocalFolderSharedSchema:
+        arguments:
+            $sharedDirectory: '%ibexa_graphql.sync.shared_directory%'
+
+    EzSystems\EzPlatformGraphQL\Schema\Sync\SharedSchema: '@EzSystems\EzPlatformGraphQL\Schema\Sync\LocalFolderSharedSchema'
+
+    EzSystems\EzPlatformGraphQL\Schema\Sync\AddTypesSolutions:
+        arguments:
+            $definitionsDirectory: '%ibexa_graphql.definitions_directory%'
+
+    EzSystems\EzPlatformGraphQL\Schema\Sync\UpdateSchemaIfNeeded:
+        arguments:
+            $definitionsDirectory: '%ibexa_graphql.definitions_directory%'
+
+    ibexa_graphql.redis:
+        class: Redis
+        calls:
+            - connect: ['%env(REDIS_GRAPHQL_HOST)%', '%env(REDIS_GRAPHQL_PORT)%']
+            - select: ['%env(REDIS_GRAPHQL_DBINDEX)%']
+
+    EzSystems\EzPlatformGraphQL\Schema\Sync\TimestampHandler: '@EzSystems\EzPlatformGraphQL\Schema\Sync\RedisTimestampHandler'
+
+    EzSystems\EzPlatformGraphQL\Schema\Sync\RedisTimestampHandler:
+        arguments:
+            $redis: '@ibexa_graphql.redis'
diff --git a/src/Schema/Sync/AddTypesSolutions.php b/src/Schema/Sync/AddTypesSolutions.php
new file mode 100644
index 00000000..26a4b7b6
--- /dev/null
+++ b/src/Schema/Sync/AddTypesSolutions.php
@@ -0,0 +1,88 @@
+<?php
+namespace EzSystems\EzPlatformGraphQL\Schema\Sync;
+
+use Overblog\GraphQLBundle\Definition\ConfigProcessor;
+use Overblog\GraphQLBundle\Definition\GlobalVariables;
+use Overblog\GraphQLBundle\Event\Events;
+use Overblog\GraphQLBundle\Event\ExecutorArgumentsEvent;
+use Overblog\GraphQLBundle\Resolver\TypeResolver;
+use Psr\Log\LoggerInterface;
+use Symfony\Component\EventDispatcher\EventSubscriberInterface;
+
+class AddTypesSolutions implements EventSubscriberInterface
+{
+    /**
+     * @var \Overblog\GraphQLBundle\Resolver\TypeResolver
+     */
+    private $typeResolver;
+
+    /**
+     * @var \Overblog\GraphQLBundle\Definition\ConfigProcessor
+     */
+    private $configProcessor;
+
+    /**
+     * @var \Overblog\GraphQLBundle\Definition\GlobalVariables
+     */
+    private $globalVariables;
+
+    /**
+     * @var string
+     */
+    private $definitionsDirectory;
+
+    /**
+     * @var \Psr\Log\LoggerInterface|null
+     */
+    private $logger;
+
+    public function __construct(TypeResolver $typeResolver, ConfigProcessor $configProcessor, GlobalVariables $globalVariables, string $definitionsDirectory, ?LoggerInterface $logger)
+    {
+        $this->typeResolver = $typeResolver;
+        $this->configProcessor = $configProcessor;
+        $this->globalVariables = $globalVariables;
+        $this->definitionsDirectory = $definitionsDirectory;
+        $this->logger = $logger;
+    }
+
+    /**
+     * @inheritDoc
+     */
+    public static function getSubscribedEvents()
+    {
+        return [Events::PRE_EXECUTOR => 'registerTypes'];
+    }
+
+    public function registerTypes(ExecutorArgumentsEvent $event)
+    {
+        $classMapFile = "$this->definitionsDirectory/__classes.map";
+        $map = include($classMapFile);
+        ksort($map);
+        foreach ($map as $class => $file) {
+            $typeName = str_replace('Overblog\\GraphQLBundle\\__DEFINITIONS__\\', '', $class);
+            $typeName = substr($typeName, 0, -4);
+            if ($this->typeResolver->hasSolution($class)) {
+                continue;
+            }
+            $this->typeResolver->addSolution(
+                $class,
+                [
+                    [$this, 'build'],
+                    [$class]
+                ],
+                [$typeName],
+                [
+                    'id' => $class,
+                    'aliases' => [$typeName],
+                    'alias' => $typeName,
+                    'generated' => true
+                ]
+            );
+        }
+    }
+
+    public function build($id)
+    {
+        return new $id($this->configProcessor, $this->globalVariables);
+    }
+}
diff --git a/src/Schema/Sync/LocalFolderSharedSchema.php b/src/Schema/Sync/LocalFolderSharedSchema.php
new file mode 100644
index 00000000..0a3e8299
--- /dev/null
+++ b/src/Schema/Sync/LocalFolderSharedSchema.php
@@ -0,0 +1,68 @@
+<?php
+/**
+ * @copyright Copyright (C) eZ Systems AS. All rights reserved.
+ * @license For full copyright and license information view LICENSE file distributed with this source code.
+ */
+
+namespace EzSystems\EzPlatformGraphQL\Schema\Sync;
+
+use Symfony\Component\Filesystem\Filesystem;
+use Symfony\Component\Finder\Finder;
+
+class LocalFolderSharedSchema implements SharedSchema
+{
+    /**
+     * @var string
+     */
+    private $sharedDirectory;
+
+    /**
+     * @var array Map of filename => file contents
+     */
+    private $files = [];
+
+    /**
+     * @var \EzSystems\EzPlatformGraphQL\Schema\Sync\TimestampHandler
+     */
+    private $timestampHandler;
+
+    public function __construct(TimestampHandler $timestampHandler, string $sharedDirectory)
+    {
+        $this->sharedDirectory = rtrim($sharedDirectory, '/');
+        $this->timestampHandler = $timestampHandler;
+    }
+
+    public function addFile(string $name, string $contents)
+    {
+        $this->files[$name] = $contents;
+    }
+
+    public function publish(int $timestamp)
+    {
+        $fs = new Filesystem();
+
+        $targetDirectory = "$this->sharedDirectory/$timestamp";
+        $fs->mkdir($targetDirectory);
+
+        foreach ($this->files as $name => $contents) {
+            $fs->dumpFile("$targetDirectory/$name", $contents);
+        }
+
+        $this->timestampHandler->set($timestamp);
+    }
+
+    public function getFiles(int $timestamp): array
+    {
+        $directory = "$this->sharedDirectory/$timestamp";
+        if (!file_exists($directory) || !is_dir($directory)) {
+            throw new \Exception("Directory not found");
+        }
+
+        $files = [];
+        foreach ((new Finder())->files()->in($directory) as $file) {
+            $files[$file->getBasename()] = $file->getContents();
+        }
+
+        return $files;
+    }
+}
diff --git a/src/Schema/Sync/RedisTimestampHandler.php b/src/Schema/Sync/RedisTimestampHandler.php
new file mode 100644
index 00000000..af2b81be
--- /dev/null
+++ b/src/Schema/Sync/RedisTimestampHandler.php
@@ -0,0 +1,38 @@
+<?php
+/**
+ * @copyright Copyright (C) eZ Systems AS. All rights reserved.
+ * @license For full copyright and license information view LICENSE file distributed with this source code.
+ */
+
+namespace EzSystems\EzPlatformGraphQL\Schema\Sync;
+
+use Redis;
+
+class RedisTimestampHandler implements TimestampHandler
+{
+    /**
+     * @var \Redis
+     */
+    private $redis;
+
+    /**
+     * @var string
+     */
+    private $key;
+
+    public function __construct(Redis $redis, string $key = 'graphql_schema_timestamp')
+    {
+        $this->redis = $redis;
+        $this->key = $key;
+    }
+
+    public function set($timestamp)
+    {
+        $this->redis->set($this->key, $timestamp);
+    }
+
+    public function get(): int
+    {
+        return $this->redis->get($this->key);
+    }
+}
diff --git a/src/Schema/Sync/SharedSchema.php b/src/Schema/Sync/SharedSchema.php
new file mode 100644
index 00000000..74dffabb
--- /dev/null
+++ b/src/Schema/Sync/SharedSchema.php
@@ -0,0 +1,27 @@
+<?php
+/**
+ * @copyright Copyright (C) eZ Systems AS. All rights reserved.
+ * @license For full copyright and license information view LICENSE file distributed with this source code.
+ */
+
+namespace EzSystems\EzPlatformGraphQL\Schema\Sync;
+
+interface SharedSchema
+{
+    /**
+     * Adds a file for publishing.
+     */
+    public function addFile(string $name, string $contents);
+
+    /**
+     * Publishes the schema.
+     */
+    public function publish(int $timestamp);
+
+    /**
+     * Gets the file from a published schema.
+     * @return array file name => file contents
+     * @throws \Exception if the directory is not found
+     */
+    public function getFiles(int $timestamp);
+}
diff --git a/src/Schema/Sync/TimestampHandler.php b/src/Schema/Sync/TimestampHandler.php
new file mode 100644
index 00000000..1a38009e
--- /dev/null
+++ b/src/Schema/Sync/TimestampHandler.php
@@ -0,0 +1,14 @@
+<?php
+/**
+ * @copyright Copyright (C) eZ Systems AS. All rights reserved.
+ * @license For full copyright and license information view LICENSE file distributed with this source code.
+ */
+
+namespace EzSystems\EzPlatformGraphQL\Schema\Sync;
+
+interface TimestampHandler
+{
+    public function set($timestamp);
+
+    public function get(): int;
+}
diff --git a/src/Schema/Sync/UpdateSchemaIfNeeded.php b/src/Schema/Sync/UpdateSchemaIfNeeded.php
new file mode 100644
index 00000000..e377f7d4
--- /dev/null
+++ b/src/Schema/Sync/UpdateSchemaIfNeeded.php
@@ -0,0 +1,103 @@
+<?php
+namespace EzSystems\EzPlatformGraphQL\Schema\Sync;
+
+use Overblog\GraphQLBundle\Event\Events;
+use Overblog\GraphQLBundle\Event\ExecutorArgumentsEvent;
+use Psr\Log\LoggerInterface;
+use Symfony\Component\EventDispatcher\EventSubscriberInterface;
+use Symfony\Component\Filesystem\Filesystem;
+use Symfony\Component\Lock\LockFactory;
+
+/**
+ * Updates the local graphql schema based on a remote one shared by the reference server.
+ */
+class UpdateSchemaIfNeeded implements EventSubscriberInterface
+{
+    /**
+     * @var \Psr\Log\LoggerInterface
+     */
+    private $logger;
+
+    /**
+     * @var \Symfony\Component\Lock\LockFactory
+     */
+    private $lockFactory;
+
+    /**
+     * @var string
+     */
+    private $definitionsDirectory;
+
+    /**
+     * @var \EzSystems\EzPlatformGraphQL\Schema\Sync\TimestampHandler
+     */
+    private $timestampHandler;
+
+    /**
+     * @var \EzSystems\EzPlatformGraphQL\Schema\Sync\SharedSchema
+     */
+    private $sharedSchema;
+
+    public function __construct(string $definitionsDirectory, SharedSchema $sharedSchema, TimestampHandler $timestampHandler, ?LoggerInterface $graphqlLogger, LockFactory $lockFactory)
+    {
+        $this->lockFactory = $lockFactory;
+        $this->logger = $graphqlLogger;
+        $this->definitionsDirectory = $definitionsDirectory;
+        $this->timestampHandler = $timestampHandler;
+        $this->sharedSchema = $sharedSchema;
+    }
+
+    /**
+     * @inheritDoc
+     */
+    public static function getSubscribedEvents()
+    {
+        return [Events::PRE_EXECUTOR => ['updateSchema', 10]];
+    }
+
+    public function updateSchema(ExecutorArgumentsEvent $event)
+    {
+        $lock = $this->lockFactory->createLock('graphql_schema_sync');
+        if (!$lock->acquire()) {
+            return;
+        }
+
+        $localSchemaTimestamp = filemtime("$this->definitionsDirectory/__classes.map");
+        $remoteSchemaTimestamp = $this->timestampHandler->get();
+        if ($remoteSchemaTimestamp === false || $remoteSchemaTimestamp < $localSchemaTimestamp) {
+            $this->logger->info("No update is needed");
+            return;
+        }
+
+        $this->logger->info("Update needed with timestamp $remoteSchemaTimestamp");
+
+        $newSchemaPath = $this->updateSchemaFromSharedResource($remoteSchemaTimestamp);
+
+        $installSchemaCallback = function() use($newSchemaPath, $lock) {
+            if ($this->logger) {
+                $this->logger->info("Applying the updated schema ($newSchemaPath -> $this->definitionsDirectory)");
+            }
+            $fs = new FileSystem();
+            $fs->remove($this->definitionsDirectory);
+            $fs->rename($newSchemaPath, $this->definitionsDirectory);
+            $lock->release();
+        };
+        register_shutdown_function($installSchemaCallback);
+    }
+
+    /**
+     * @return string the path to the new schema
+     */
+    private function updateSchemaFromSharedResource(int $timestamp): string
+    {
+        $updatePath = $this->definitionsDirectory . '_' . time();
+        $this->logger->info("Synchronizing files from shared schema to $updatePath");
+
+        $fs = new FileSystem();
+        foreach ($this->sharedSchema->getFiles($timestamp) as $name => $contents) {
+            $fs->dumpFile("$updatePath/$name", $contents);
+        }
+
+        return $updatePath;
+    }
+}

From 573e03e0021ccd63f9aad31878b0a8b180eaeccc Mon Sep 17 00:00:00 2001
From: Bertrand Dunogier <bertrand.dunogier@ez.no>
Date: Wed, 24 Nov 2021 11:40:24 +0100
Subject: [PATCH 2/3] Moved schema update download to shutdown function

---
 src/Schema/Sync/UpdateSchemaIfNeeded.php | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/src/Schema/Sync/UpdateSchemaIfNeeded.php b/src/Schema/Sync/UpdateSchemaIfNeeded.php
index e377f7d4..06ab1dce 100644
--- a/src/Schema/Sync/UpdateSchemaIfNeeded.php
+++ b/src/Schema/Sync/UpdateSchemaIfNeeded.php
@@ -71,9 +71,8 @@ public function updateSchema(ExecutorArgumentsEvent $event)
 
         $this->logger->info("Update needed with timestamp $remoteSchemaTimestamp");
 
-        $newSchemaPath = $this->updateSchemaFromSharedResource($remoteSchemaTimestamp);
-
-        $installSchemaCallback = function() use($newSchemaPath, $lock) {
+        $installSchemaCallback = function() use($remoteSchemaTimestamp, $lock) {
+            $newSchemaPath = $this->updateSchemaFromSharedResource($remoteSchemaTimestamp);
             if ($this->logger) {
                 $this->logger->info("Applying the updated schema ($newSchemaPath -> $this->definitionsDirectory)");
             }

From ce8b785682da48ceb8f0bab0a07012be82a156b8 Mon Sep 17 00:00:00 2001
From: Bertrand Dunogier <bertrand.dunogier@ez.no>
Date: Wed, 24 Nov 2021 16:38:51 +0100
Subject: [PATCH 3/3] [schema sync] Implemented (optional) AWS S3 sync

---
 composer.json                                 |  5 +-
 .../EzSystemsEzPlatformGraphQLExtension.php   |  8 ++
 .../config/services/schema_sync.yaml          | 10 +-
 .../config/services/schema_sync_s3.yaml       | 17 ++++
 src/Schema/Sync/README.md                     | 68 +++++++++++++
 src/Schema/Sync/RedisTimestampHandler.php     |  4 +-
 src/Schema/Sync/S3SharedSchema.php            | 97 +++++++++++++++++++
 7 files changed, 201 insertions(+), 8 deletions(-)
 create mode 100644 src/Resources/config/services/schema_sync_s3.yaml
 create mode 100644 src/Schema/Sync/README.md
 create mode 100644 src/Schema/Sync/S3SharedSchema.php

diff --git a/composer.json b/composer.json
index 82ebe38e..f1ef5087 100644
--- a/composer.json
+++ b/composer.json
@@ -19,7 +19,6 @@
         "ezsystems/ezplatform-admin-ui": "^2.0@dev",
         "ezsystems/ezplatform-rest": "^1.2@dev",
         "ezsystems/ezplatform-richtext": "^2.0@dev",
-        "ext-redis": "*",
         "lexik/jwt-authentication-bundle": "^2.8",
         "overblog/graphql-bundle": "^0.12",
         "erusev/parsedown": "^1.7",
@@ -44,6 +43,10 @@
         "ezsystems/ezplatform-code-style": "^0.1.0",
         "mikey179/vfsstream": "^1.6"
     },
+    "suggest": {
+        "aws/aws-sdk-php": "For compiled schema synchronization over AWS-S3",
+        "ext-redis": "*"
+    },
     "autoload": {
         "psr-4": {
             "EzSystems\\EzPlatformGraphQL\\": "src",
diff --git a/src/DependencyInjection/EzSystemsEzPlatformGraphQLExtension.php b/src/DependencyInjection/EzSystemsEzPlatformGraphQLExtension.php
index 12603c1e..18282b39 100644
--- a/src/DependencyInjection/EzSystemsEzPlatformGraphQLExtension.php
+++ b/src/DependencyInjection/EzSystemsEzPlatformGraphQLExtension.php
@@ -6,6 +6,7 @@
  */
 namespace EzSystems\EzPlatformGraphQL\DependencyInjection;
 
+use Aws\S3\S3Client;
 use EzSystems\EzPlatformGraphQL\DependencyInjection\GraphQL\YamlSchemaProvider;
 use Symfony\Component\Config\FileLocator;
 use Symfony\Component\DependencyInjection\ContainerBuilder;
@@ -42,6 +43,13 @@ public function load(array $configs, ContainerBuilder $container)
         $loader->load('services/schema_sync.yaml');
         $loader->load('services/services.yaml');
         $loader->load('default_settings.yaml');
+
+        if (extension_loaded('redis')) {
+            $loader->load('services/schema_sync.yaml');
+            if (class_exists(S3Client::class)) {
+                $loader->load('services/schema_sync_s3.yaml');
+            }
+        }
     }
 
     /**
diff --git a/src/Resources/config/services/schema_sync.yaml b/src/Resources/config/services/schema_sync.yaml
index eefbf2d1..d712092c 100644
--- a/src/Resources/config/services/schema_sync.yaml
+++ b/src/Resources/config/services/schema_sync.yaml
@@ -7,6 +7,9 @@ services:
         autoconfigure: true
         autowire: true
         public: false
+        bind:
+            EzSystems\EzPlatformGraphQL\Schema\Sync\TimestampHandler: '@EzSystems\EzPlatformGraphQL\Schema\Sync\RedisTimestampHandler'
+            Redis $graphQLSyncRedis: '@ibexa_graphql.sync.redis_client'
 
     EzSystems\EzPlatformGraphQL\Command\PublishSchemaCommand:
         arguments:
@@ -26,14 +29,11 @@ services:
         arguments:
             $definitionsDirectory: '%ibexa_graphql.definitions_directory%'
 
-    ibexa_graphql.redis:
+    ibexa_graphql.sync.redis_client:
         class: Redis
         calls:
             - connect: ['%env(REDIS_GRAPHQL_HOST)%', '%env(REDIS_GRAPHQL_PORT)%']
             - select: ['%env(REDIS_GRAPHQL_DBINDEX)%']
 
-    EzSystems\EzPlatformGraphQL\Schema\Sync\TimestampHandler: '@EzSystems\EzPlatformGraphQL\Schema\Sync\RedisTimestampHandler'
+    EzSystems\EzPlatformGraphQL\Schema\Sync\RedisTimestampHandler: ~
 
-    EzSystems\EzPlatformGraphQL\Schema\Sync\RedisTimestampHandler:
-        arguments:
-            $redis: '@ibexa_graphql.redis'
diff --git a/src/Resources/config/services/schema_sync_s3.yaml b/src/Resources/config/services/schema_sync_s3.yaml
new file mode 100644
index 00000000..e241d209
--- /dev/null
+++ b/src/Resources/config/services/schema_sync_s3.yaml
@@ -0,0 +1,17 @@
+services:
+    _defaults:
+        bind:
+            Aws\S3\S3Client $graphQLSyncS3Client: '@ibexa_graphql.sync.s3_client'
+            EzSystems\EzPlatformGraphQL\Schema\Sync\TimestampHandler: '@EzSystems\EzPlatformGraphQL\Schema\Sync\RedisTimestampHandler'
+
+    ibexa_graphql.sync.s3_client:
+        class: Aws\S3\S3Client
+        arguments:
+            -   version: '2006-03-01'
+                region: '%env(GRAPHQL_SYNC_S3_REGION)%'
+
+    EzSystems\EzPlatformGraphQL\Schema\Sync\S3SharedSchema:
+        arguments:
+            $bucket: '%env(GRAPHQL_SYNC_S3_BUCKET)%'
+
+    EzSystems\EzPlatformGraphQL\Schema\Sync\SharedSchema: '@EzSystems\EzPlatformGraphQL\Schema\Sync\S3SharedSchema'
diff --git a/src/Schema/Sync/README.md b/src/Schema/Sync/README.md
new file mode 100644
index 00000000..33d84c7c
--- /dev/null
+++ b/src/Schema/Sync/README.md
@@ -0,0 +1,68 @@
+# GraphQL schema sync
+
+An experimental mechanism for publishing a compiled schema so that secondary servers can pull it and install it without recompiling their own containe.
+
+## Configuration
+
+### Redis
+The feature requires Redis for publishing the latest schema timestamp (it is suggested in `composer.json`).
+
+The feature comes with a default redis client service, `ibexa_graphql.sync.redis_client`.
+It is configured using the following environment variables:
+```.dotenv
+REDIS_GRAPHQL_HOST=1.2.3.4
+REDIS_GRAPHQL_PORT=6379
+REDIS_GRAPHQL_DBINDEX=0
+```
+
+If you want to use your own client, you can redefined the service with the same name in your 
+project's services definitions.
+
+If you already have your own and want to re-use it, create an alias with that name:
+```yaml
+# config/services.yaml
+services:
+    ibexa_graphql.sync.redis_client: '@app.redis_client'
+```
+
+### AWS S3
+Amazon S3 can be used to publish the schema files. To enable it, make sure that `aws/aws-sdk-php`
+is installed on your project.
+
+It uses a default client service named `ibexa_graphql.sync.s3_client`, based on the default
+environment variables expected by the SDK:
+
+```dotenv
+AWS_ACCESS_KEY_ID=
+AWS_SECRET_ACCESS_KEY=
+```
+
+If you already have an s3 client service, alias it to `ibexa_graphql.sync.s3_client`:
+```yaml
+# config/services.yaml
+services:
+    ibexa_graphql.sync.s3_client: '@app.s3_client'
+```
+
+The feature also requires two extra settings for the bucket and the region:
+```dotenv
+GRAPHQL_SYNC_S3_BUCKET=ibexa-graphql
+GRAPHQL_SYNC_S3_REGION=eu-west-1
+```
+
+## Usage
+One server will do the schema generation + compiling, and run a command
+(`ibexa:graphql:publish-schema`) to publish the schema. The command can be executed during a deployment process,
+or manually.
+
+Publishing will:
+
+1. push the compiled schema (`%kernel.cache_dir%/overblog/graphql-bundle/__definitions__/*`) to a SharedSchema
+2. set the published schema timestamp using a TimestampHandler.
+
+Secondary servers, when a GraphQL query is executed (`UpdateSchemaIfNeeded` subscriber), will compare the timestamp to
+theirs (modification time of `__classes.map`). If the remote schema is newer, it will be pulled and installed on shutdown.
+
+Since the graphql schema types are compiled into the container as services, types that were added to the published schema
+(new content types, etc) need to be registered on runtime. This is done by the `Schema\Sync\AddTypesSolutions` subscriber.
+It checks which of the type classes do not have a solution in the current schema, and adds them to it.
diff --git a/src/Schema/Sync/RedisTimestampHandler.php b/src/Schema/Sync/RedisTimestampHandler.php
index af2b81be..271a56b2 100644
--- a/src/Schema/Sync/RedisTimestampHandler.php
+++ b/src/Schema/Sync/RedisTimestampHandler.php
@@ -20,9 +20,9 @@ class RedisTimestampHandler implements TimestampHandler
      */
     private $key;
 
-    public function __construct(Redis $redis, string $key = 'graphql_schema_timestamp')
+    public function __construct(Redis $graphQLSyncRedis, string $key = 'graphql_schema_timestamp')
     {
-        $this->redis = $redis;
+        $this->redis = $graphQLSyncRedis;
         $this->key = $key;
     }
 
diff --git a/src/Schema/Sync/S3SharedSchema.php b/src/Schema/Sync/S3SharedSchema.php
new file mode 100644
index 00000000..97c20a89
--- /dev/null
+++ b/src/Schema/Sync/S3SharedSchema.php
@@ -0,0 +1,97 @@
+<?php
+/**
+ * @copyright Copyright (C) eZ Systems AS. All rights reserved.
+ * @license For full copyright and license information view LICENSE file distributed with this source code.
+ */
+
+namespace EzSystems\EzPlatformGraphQL\Schema\Sync;
+
+use Aws\Result;
+use Aws\S3\Exception\S3Exception;
+use Aws\S3\S3Client;
+use EzSystems\EzPlatformGraphQL\Schema\Sync\SharedSchema;
+use EzSystems\EzPlatformGraphQL\Schema\Sync\TimestampHandler;
+use Symfony\Component\Finder\Finder;
+
+class S3SharedSchema implements SharedSchema
+{
+    /**
+     * @var array Map of filename => file contents
+     */
+    private $files = [];
+
+    /**
+     * @var \EzSystems\EzPlatformGraphQL\Schema\Sync\TimestampHandler
+     */
+    private $timestampHandler;
+    /**
+     * @var \Aws\S3\S3Client
+     */
+    private $s3;
+
+    private $bucket;
+
+    public function __construct(TimestampHandler $timestampHandler, S3Client $graphQLSyncS3Client, string $bucket)
+    {
+        $this->timestampHandler = $timestampHandler;
+        $this->s3 = $graphQLSyncS3Client;
+        $this->bucket = $bucket;
+    }
+
+    public function addFile(string $name, string $contents)
+    {
+        $this->files[$name] = $contents;
+    }
+
+    public function publish(int $timestamp)
+    {
+        foreach ($this->files as $name => $contents) {
+            $this->putFileToS3("$timestamp/$name", $contents);
+        }
+
+        $this->timestampHandler->set($timestamp);
+    }
+
+    public function getFiles(int $timestamp): array
+    {
+        if (!$this->hasFileOnS3("$timestamp/__classes.map")) {
+            throw new \Exception("Shared schema not found");
+        }
+
+        $files = [];
+
+        $prefix = "$timestamp/";
+        $listResult = $this->s3->listObjectsV2(['Bucket' => $this->bucket, 'Prefix' => $prefix]);
+        foreach ($listResult->get('Contents') as $listItem) {
+            $fileResult = $this->s3->getObject(['Bucket' => $this->bucket, 'Key' => $listItem['Key']]);
+            $fileName = str_replace($prefix, '', $listItem['Key']);
+            $files[$fileName] = $fileResult->get('Body')->getContents();
+        }
+
+        return $files;
+    }
+
+    private function putFileToS3(string $name, string $contents): void
+    {
+        try {
+            $this->s3->putObject([
+                'Bucket' => $this->bucket,
+                'Key' => $name,
+                'Body' => $contents,
+            ]);
+        } catch (S3Exception $e) {
+            throw new \Exception("Error creating file", 0, $e);
+        }
+    }
+
+    private function hasFileOnS3(string $path): bool
+    {
+        try {
+            $this->s3->getObject(['Bucket' => $this->bucket, 'Key' => $path]);
+        } catch (S3Exception $e) {
+            return false;
+        }
+
+        return true;
+    }
+}