sqlite: use WAL journal mode by default

src/Database/TenantDatabaseManagers/SQLiteDatabaseManager.php

@@ -4,6 +4,8 @@ declare(strict_types=1);
 
 namespace Stancl\Tenancy\Database\TenantDatabaseManagers;
 
+use AssertionError;
+use PDO;
 use Stancl\Tenancy\Database\Contracts\TenantDatabaseManager;
 use Stancl\Tenancy\Database\Contracts\TenantWithDatabase;
 use Throwable;
@@ -15,10 +17,30 @@ class SQLiteDatabaseManager implements TenantDatabaseManager
      */
     public static string|null $path = null;
 
+    /**
+     * Should the WAL journal mode be used for newly created databases.
+     *
+     * @see https://www.sqlite.org/pragma.html#pragma_journal_mode
+     */
+    public static bool $WAL = true;
+
     public function createDatabase(TenantWithDatabase $tenant): bool
     {
         try {
-            return (bool) file_put_contents($this->getPath($tenant->database()->getName()), '');
+            if (file_put_contents($path = $this->getPath($tenant->database()->getName()), '') === false) {
+                return false;
+            }
+
+            if (static::$WAL) {
+                $pdo = new PDO('sqlite:' . $path);
+                $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
+
+                assert($pdo->query("pragma journal_mode = wal")->fetch(PDO::FETCH_ASSOC)['journal_mode'] === 'wal', "Unable to set journal mode to wal.");
+            }
+
+            return true;
+        } catch (AssertionError $e) {
+            throw $e;
         } catch (Throwable) {
             return false;
         }

tests/TenantDatabaseManagerTest.php

@@ -145,6 +145,36 @@ test('db name is prefixed with db path when sqlite is used', function () {
     expect(database_path('foodb'))->toBe(config('database.connections.tenant.database'));
 });
 
+test('sqlite databases use the WAL journal mode by default', function (bool|null $wal) {
+    $expected = $wal ? 'wal' : 'delete';
+    if ($wal !== null) {
+        SQLiteDatabaseManager::$WAL = $wal;
+    } else {
+        // default behavior
+        $expected = 'wal';
+    }
+
+    Event::listen(TenantCreated::class, JobPipeline::make([CreateDatabase::class])->send(function (TenantCreated $event) {
+        return $event->tenant;
+    })->toListener());
+
+    $tenant = Tenant::create([
+        'tenancy_db_connection' => 'sqlite',
+    ]);
+
+    $dbPath = database_path($tenant->database()->getName());
+
+    expect(file_exists($dbPath))->toBeTrue();
+
+    $db = new PDO('sqlite:' . $dbPath);
+    $db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
+
+    expect($db->query('pragma journal_mode')->fetch(PDO::FETCH_ASSOC)['journal_mode'])->toBe($expected);
+
+    // cleanup
+    SQLiteDatabaseManager::$WAL = true;
+})->with([true, false, null]);
+
 test('schema manager uses schema to separate tenant dbs', function () {
     config([
         'tenancy.database.managers.pgsql' => PostgreSQLSchemaManager::class,