Add cache fallback into DB library

Dockerfile

@@ -34,6 +34,8 @@ RUN \
     git \
     brotli-dev \
     linux-headers \
+    docker-cli \
+    docker-cli-compose \
   && docker-php-ext-install opcache pgsql pdo_mysql pdo_pgsql \
   && apk del postgresql-dev \
   && rm -rf /var/cache/apk/*

docker-compose.yml

@@ -15,6 +15,8 @@ services:
       - ./dev:/usr/src/code/dev
       - ./phpunit.xml:/usr/src/code/phpunit.xml
       - ./dev/xdebug.ini:/usr/local/etc/php/conf.d/xdebug.ini
+      - /var/run/docker.sock:/var/run/docker.sock
+      - ./docker-compose.yml:/usr/src/code/docker-compose.yml
 
   adminer:
     image: adminer

src/Database/Adapter.php

@@ -900,6 +900,13 @@ abstract public function getSupportForCastIndexArray(): bool;
      */
     abstract public function getSupportForUpserts(): bool;
 
+    /**
+     * Is Cache Fallback supported?
+     *
+     * @return bool
+     */
+    abstract public function getSupportForCacheSkipOnFailure(): bool;
+
     /**
      * Get current attribute count from collection document
      *

src/Database/Adapter/Mongo.php

@@ -1800,6 +1800,16 @@ public function getSupportForGetConnectionId(): bool
         return false;
     }
 
+    /**
+     * Is cache fallback supported?
+     *
+     * @return bool
+     */
+    public function getSupportForCacheSkipOnFailure(): bool
+    {
+        return false;
+    }
+
     /**
      * Is get schema attributes supported?
      *

src/Database/Adapter/SQL.php

@@ -402,6 +402,16 @@ public function getSupportForGetConnectionId(): bool
         return true;
     }
 
+    /**
+     * Is cache fallback supported?
+     *
+     * @return bool
+     */
+    public function getSupportForCacheSkipOnFailure(): bool
+    {
+        return true;
+    }
+
     /**
      * Get current attribute count from collection document
      *

src/Database/Adapter/SQLite.php

@@ -220,15 +220,7 @@ public function createCollection(string $name, array $attributes = [], array $in
             $this->createIndex("{$id}_perms", '_index_2', Database::INDEX_KEY, ['_permission', '_type'], [], []);
 
         } catch (PDOException $e) {
-            $e = $this->processException($e);
-
-            if (!($e instanceof Duplicate)) {
-                $this->getPDO()
-                    ->prepare("DROP TABLE IF EXISTS {$this->getSQLTable($id)}, {$this->getSQLTable($id . '_perms')};")
-                    ->execute();
-            }
-
-            throw $e;
+            throw $this->processException($e);
         }
         return true;
     }

src/Database/Database.php

@@ -4,6 +4,7 @@
 
 use Exception;
 use Utopia\Cache\Cache;
+use Utopia\CLI\Console;
 use Utopia\Database\Exception as DatabaseException;
 use Utopia\Database\Exception\Authorization as AuthorizationException;
 use Utopia\Database\Exception\Conflict as ConflictException;
@@ -441,14 +442,20 @@ function (?string $value) {
 
     /**
      * Add listener to events
+     * Passing a null $callback will remove the listener
      *
      * @param string $event
      * @param string $name
-     * @param callable $callback
+     * @param ?callable $callback
      * @return static
      */
-    public function on(string $event, string $name, callable $callback): static
+    public function on(string $event, string $name, ?callable $callback): static
     {
+        if (empty($callback)) {
+            unset($this->listeners[$event][$name]);
+            return $this;
+        }
+
         if (!isset($this->listeners[$event])) {
             $this->listeners[$event] = [];
         }
@@ -2992,8 +2999,15 @@ public function getDocument(string $collection, string $id, array $queries = [],
             $documentCacheHash .= ':' . \md5(\implode($selections));
         }
 
-        if ($cache = $this->cache->load($documentCacheKey, self::TTL, $documentCacheHash)) {
-            $document = new Document($cache);
+        try {
+            $cached = $this->cache->load($documentCacheKey, self::TTL, $documentCacheHash);
+        } catch (Exception $e) {
+            Console::warning('Warning: Failed to get document from cache: ' . $e->getMessage());
+            $cached = null;
+        }
+
+        if ($cached) {
+            $document = new Document($cached);
 
             if ($collection->getId() !== self::METADATA) {
                 if (!$validator->isValid([
@@ -3042,8 +3056,12 @@ public function getDocument(string $collection, string $id, array $queries = [],
 
         // Don't save to cache if it's part of a relationship
         if (empty($relationships)) {
-            $this->cache->save($documentCacheKey, $document->getArrayCopy(), $documentCacheHash);
-            $this->cache->save($collectionCacheKey, 'empty', $documentCacheKey);
+            try {
+                $this->cache->save($documentCacheKey, $document->getArrayCopy(), $documentCacheHash);
+                $this->cache->save($collectionCacheKey, 'empty', $documentCacheKey);
+            } catch (Exception $e) {
+                Console::warning('Failed to save document to cache: ' . $e->getMessage());
+            }
         }
 
         // Remove internal attributes if not queried for select query
@@ -3962,6 +3980,7 @@ public function updateDocument(string $collection, string $id, Document $documen
             }
 
             $this->adapter->updateDocument($collection->getId(), $id, $document);
+            $this->purgeCachedDocument($collection->getId(), $id);
 
             return $document;
         });
@@ -3972,7 +3991,6 @@ public function updateDocument(string $collection, string $id, Document $documen
 
         $document = $this->decode($collection, $document);
 
-        $this->purgeCachedDocument($collection->getId(), $id);
         $this->trigger(self::EVENT_DOCUMENT_UPDATE, $document);
 
         return $document;
@@ -4888,10 +4906,12 @@ public function deleteDocument(string $collection, string $id): bool
                 $document = $this->silent(fn () => $this->deleteDocumentRelationships($collection, $document));
             }
 
-            return $this->adapter->deleteDocument($collection->getId(), $id);
-        });
+            $result = $this->adapter->deleteDocument($collection->getId(), $id);
 
-        $this->purgeCachedDocument($collection->getId(), $id);
+            $this->purgeCachedDocument($collection->getId(), $id);
+
+            return $result;
+        });
 
         $this->trigger(self::EVENT_DOCUMENT_DELETE, $document);
 
@@ -5424,6 +5444,7 @@ public function deleteDocuments(string $collection, array $queries = [], int $ba
     public function purgeCachedCollection(string $collectionId): bool
     {
         $collectionKey = $this->cacheName . '-cache-' . $this->getNamespace() . ':' . $this->adapter->getTenant() . ':collection:' . $collectionId;
+
         $documentKeys = $this->cache->list($collectionKey);
         foreach ($documentKeys as $documentKey) {
             $this->cache->purge($documentKey);

src/Database/Mirror.php

@@ -157,7 +157,7 @@ public function disableValidation(): static
         return $this;
     }
 
-    public function on(string $event, string $name, callable $callback): static
+    public function on(string $event, string $name, ?callable $callback): static
     {
         $this->source->on($event, $name, $callback);
 

tests/e2e/Adapter/Base.php

@@ -5,6 +5,7 @@
 use Exception;
 use PHPUnit\Framework\TestCase;
 use Throwable;
+use Utopia\CLI\Console;
 use Utopia\Database\Adapter\SQL;
 use Utopia\Database\Database;
 use Utopia\Database\DateTime;
@@ -17683,6 +17684,77 @@ public function testEvents(): void
             $database->deleteAttribute($collectionId, 'attr1');
             $database->deleteCollection($collectionId);
             $database->delete('hellodb');
+
+            // Remove all listeners
+            $database->on(Database::EVENT_ALL, 'test', null);
+            $database->on(Database::EVENT_ALL, 'should-not-execute', null);
         });
     }
+
+    public function testCacheFallback(): void
+    {
+        if (!static::getDatabase()->getAdapter()->getSupportForCacheSkipOnFailure()) {
+            $this->expectNotToPerformAssertions();
+            return;
+        }
+
+        Authorization::cleanRoles();
+        Authorization::setRole(Role::any()->toString());
+        $database = static::getDatabase();
+
+        // Write mock data
+        $database->createCollection('testRedisFallback', attributes: [
+            new Document([
+                '$id' => ID::custom('string'),
+                'type' => Database::VAR_STRING,
+                'size' => 767,
+                'required' => true,
+            ])
+        ], permissions: [
+            Permission::read(Role::any()),
+            Permission::create(Role::any()),
+            Permission::update(Role::any()),
+            Permission::delete(Role::any())
+        ]);
+
+        $database->createDocument('testRedisFallback', new Document([
+            '$id' => 'doc1',
+            'string' => 'text📝',
+        ]));
+
+        $database->createIndex('testRedisFallback', 'index1', Database::INDEX_KEY, ['string']);
+        $this->assertCount(1, $database->find('testRedisFallback', [Query::equal('string', ['text📝'])]));
+
+        // Bring down Redis
+        $stdout = '';
+        $stderr = '';
+        Console::execute('docker ps -a --filter "name=utopia-redis" --format "{{.Names}}" | xargs -r docker stop', "", $stdout, $stderr);
+
+        // Check we can read data still
+        $this->assertCount(1, $database->find('testRedisFallback', [Query::equal('string', ['text📝'])]));
+        $this->assertFalse(($database->getDocument('testRedisFallback', 'doc1'))->isEmpty());
+
+        // Check we cannot modify data
+        try {
+            $database->updateDocument('testRedisFallback', 'doc1', new Document([
+                'string' => 'text📝 updated',
+            ]));
+            $this->fail('Failed to throw exception');
+        } catch (\Throwable $e) {
+            $this->assertEquals('Redis server redis:6379 went away', $e->getMessage());
+        }
+
+        try {
+            $database->deleteDocument('testRedisFallback', 'doc1');
+            $this->fail('Failed to throw exception');
+        } catch (\Throwable $e) {
+            $this->assertEquals('Redis server redis:6379 went away', $e->getMessage());
+        }
+
+        // Bring backup Redis
+        Console::execute('docker ps -a --filter "name=utopia-redis" --format "{{.Names}}" | xargs -r docker start', "", $stdout, $stderr);
+        sleep(5);
+
+        $this->assertCount(1, $database->find('testRedisFallback', [Query::equal('string', ['text📝'])]));
+    }
 }

tests/e2e/Adapter/MariaDBTest.php

@@ -41,6 +41,7 @@ public static function getDatabase(bool $fresh = false): Database
         $dbPass = 'password';
 
         $pdo = new PDO("mysql:host={$dbHost};port={$dbPort};charset=utf8mb4", $dbUser, $dbPass, MariaDB::getPDOAttributes());
+
         $redis = new Redis();
         $redis->connect('redis', 6379);
         $redis->flushAll();

tests/e2e/Adapter/MirrorTest.php

@@ -45,6 +45,7 @@ protected static function getDatabase(bool $fresh = false): Mirror
         $dbPass = 'password';
 
         $pdo = new PDO("mysql:host={$dbHost};port={$dbPort};charset=utf8mb4", $dbUser, $dbPass, MariaDB::getPDOAttributes());
+
         $redis = new Redis();
         $redis->connect('redis');
         $redis->flushAll();
@@ -59,6 +60,7 @@ protected static function getDatabase(bool $fresh = false): Mirror
         $mirrorPass = 'password';
 
         $mirrorPdo = new PDO("mysql:host={$mirrorHost};port={$mirrorPort};charset=utf8mb4", $mirrorUser, $mirrorPass, MariaDB::getPDOAttributes());
+
         $mirrorRedis = new Redis();
         $mirrorRedis->connect('redis-mirror');
         $mirrorRedis->flushAll();

tests/e2e/Adapter/MySQLTest.php

@@ -45,7 +45,6 @@ public static function getDatabase(): Database
         $redis = new Redis();
         $redis->connect('redis', 6379);
         $redis->flushAll();
-
         $cache = new Cache(new RedisAdapter($redis));
 
         $database = new Database(new MySQL($pdo), $cache);

tests/e2e/Adapter/SQLiteTest.php

@@ -46,9 +46,8 @@ public static function getDatabase(): Database
         $pdo = new PDO("sqlite:" . $dsn, null, null, SQLite::getPDOAttributes());
 
         $redis = new Redis();
-        $redis->connect('redis');
+        $redis->connect('redis', 6379);
         $redis->flushAll();
-
         $cache = new Cache(new RedisAdapter($redis));
 
         $database = new Database(new SQLite($pdo), $cache);