Adds configuration to run ArcadeDBServer in READ_ONLY mode.

engine/src/main/java/com/arcadedb/GlobalConfiguration.java

@@ -204,14 +204,19 @@ public Object call(final Object value) {
 
   SERVER_DATABASE_LOADATSTARTUP("arcadedb.server.databaseLoadAtStartup", "Open all the available databases at server startup", Boolean.class, true),
 
-  SERVER_PLUGINS("arcadedb.server.plugins", "List of server plugins to install. The format to load a plugin is: `<pluginName>:<pluginFullClass>`", String.class,
-      ""),
-
   SERVER_DEFAULT_DATABASES("arcadedb.server.defaultDatabases",
       "The default databases created when the server starts. The format is `(<database-name>[(<user-name>:<user-passwd>[:<user-group>])[,]*])[{import|restore:<URL>}][;]*'. Pay attention on using `;`"
           + " to separate databases and `,` to separate credentials. The supported actions are `import` and `restore`. Example: `Universe[elon:musk:admin];Amiga[Jay:Miner,Jack:Tramiel]{import:/tmp/movies.tgz}`",
       String.class, ""),
 
+  SERVER_DEFAULT_DATABASE_MODE("arcadedb.server.defaultDatabaseMode",
+      "The default mode to load pre-existing databases. The value must match a com.arcadedb.engine.PaginatedFile.MODE enum value: {READ_ONLY, READ_WRITE}"
+      + "Databases which are newly created will always be opened READ_WRITE.",
+      String.class, "READ_WRITE"),
+
+  SERVER_PLUGINS("arcadedb.server.plugins", "List of server plugins to install. The format to load a plugin is: `<pluginName>:<pluginFullClass>`", String.class,
+      ""),
+
   // SERVER HTTP
   SERVER_HTTP_INCOMING_HOST("arcadedb.server.httpIncomingHost", "TCP/IP host name used for incoming HTTP connections", String.class, "0.0.0.0"),
 

server/src/main/java/com/arcadedb/server/ArcadeDBServer.java

@@ -18,13 +18,16 @@
  */
 package com.arcadedb.server;
 
+import static com.arcadedb.engine.PaginatedFile.MODE.READ_WRITE;
+
 import com.arcadedb.Constants;
 import com.arcadedb.ContextConfiguration;
 import com.arcadedb.GlobalConfiguration;
 import com.arcadedb.database.Database;
 import com.arcadedb.database.DatabaseFactory;
 import com.arcadedb.database.DatabaseInternal;
 import com.arcadedb.database.EmbeddedDatabase;
+import com.arcadedb.engine.PaginatedFile;
 import com.arcadedb.exception.CommandExecutionException;
 import com.arcadedb.exception.ConfigurationException;
 import com.arcadedb.exception.DatabaseIsClosedException;
@@ -350,10 +353,14 @@ public synchronized Database getDatabase(final String databaseName, final boolea
 
       factory.setSecurity(getSecurity());
 
+      final PaginatedFile.MODE defaultDbMode = Optional.ofNullable(
+          GlobalConfiguration.SERVER_DEFAULT_DATABASE_MODE.getValueAsEnum(PaginatedFile.MODE.class))
+          .orElse(READ_WRITE);
+
       if (createIfNotExists)
-        db = (DatabaseInternal) (factory.exists() ? factory.open() : factory.create());
+        db = (DatabaseInternal) (factory.exists() ? factory.open(defaultDbMode) : factory.create());
       else
-        db = (DatabaseInternal) factory.open();
+        db = (DatabaseInternal) factory.open(defaultDbMode);
 
       if (configuration.getValueAsBoolean(GlobalConfiguration.HA_ENABLED))
         db = new ReplicatedDatabase(this, (EmbeddedDatabase) db);

server/src/test/java/com/arcadedb/server/ServerDefaultDatabasesIT.java

@@ -18,6 +18,8 @@
  */
 package com.arcadedb.server;
 
+import static com.arcadedb.engine.PaginatedFile.MODE.READ_WRITE;
+
 import com.arcadedb.ContextConfiguration;
 import com.arcadedb.GlobalConfiguration;
 import com.arcadedb.database.DatabaseInternal;
@@ -77,6 +79,9 @@ public void checkDefaultDatabases() throws IOException {
     Assertions.assertTrue(getServer(0).existsDatabase("Universe"));
     Assertions.assertTrue(getServer(0).existsDatabase("Amiga"));
 
+    Assertions.assertTrue(READ_WRITE.equals(getServer(0).getDatabase("Universe").getMode()));
+    Assertions.assertTrue(READ_WRITE.equals(getServer(0).getDatabase("Amiga").getMode()));
+
     ((DatabaseInternal) getServer(0).getDatabase("Universe")).getEmbedded().drop();
     ((DatabaseInternal) getServer(0).getDatabase("Amiga")).getEmbedded().drop();
   }

server/src/test/java/com/arcadedb/server/ServerReadOnlyDatabasesIT.java

@@ -0,0 +1,54 @@
+/*
+ * Copyright © 2022-present Arcade Data Ltd (info@arcadedata.com)
+ *
+ * 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.
+ *
+ * SPDX-FileCopyrightText: 2022-present Arcade Data Ltd (info@arcadedata.com)
+ * SPDX-License-Identifier: Apache-2.0
+ */
+package com.arcadedb.server;
+
+import static com.arcadedb.engine.PaginatedFile.MODE.READ_ONLY;
+
+import com.arcadedb.ContextConfiguration;
+import com.arcadedb.GlobalConfiguration;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+import java.io.*;
+
+public class ServerReadOnlyDatabasesIT extends BaseGraphServerTest {
+
+  @Override
+  protected boolean isCreateDatabases() {
+    return false;
+  }
+
+  @Override
+  protected void populateDatabase() {
+  }
+
+  protected void onServerConfiguration(final ContextConfiguration config) {
+    config.setValue(GlobalConfiguration.SERVER_DEFAULT_DATABASES, "Universe[elon:musk:admin];Amiga[Jay:Miner:admin,Jack:Tramiel:admin,root]");
+    config.setValue(GlobalConfiguration.SERVER_DEFAULT_DATABASE_MODE, "READ_ONLY");
+  }
+
+  @Test
+  public void checkDefaultDatabases() throws IOException {
+    Assertions.assertTrue(getServer(0).existsDatabase("Universe"));
+    Assertions.assertTrue(getServer(0).existsDatabase("Amiga"));
+
+    Assertions.assertTrue(READ_ONLY.equals(getServer(0).getDatabase("Universe").getMode()));
+    Assertions.assertTrue(READ_ONLY.equals(getServer(0).getDatabase("Amiga").getMode()));
+  }
+}