Add validator for config key

Author: Pearl1594

api/src/main/java/org/apache/cloudstack/backup/BackupManager.java

@@ -26,6 +26,7 @@
 import org.apache.cloudstack.api.command.user.backup.ListBackupOfferingsCmd;
 import org.apache.cloudstack.api.command.user.backup.ListBackupsCmd;
 import org.apache.cloudstack.framework.config.ConfigKey;
+import org.apache.cloudstack.framework.config.ValidatedConfigKey;
 import org.apache.cloudstack.framework.config.Configurable;
 
 import com.cloud.utils.Pair;
@@ -42,10 +43,20 @@ public interface BackupManager extends BackupService, Configurable, PluggableSer
             "false",
             "Is backup and recovery framework enabled.", false, ConfigKey.Scope.Zone);
 
-    ConfigKey<String> BackupProviderPlugin = new ConfigKey<>("Advanced", String.class,
+    ConfigKey<String> BackupProviderPlugin = new ValidatedConfigKey<>("Advanced", String.class,
             "backup.framework.provider.plugin",
             "dummy",
-            "The backup and recovery provider plugin.", true, ConfigKey.Scope.Zone, BackupFrameworkEnabled.key());
+            "The backup and recovery provider plugin. Valid plugin values: dummy, veeam, networker and nas",
+            true, ConfigKey.Scope.Zone, BackupFrameworkEnabled.key(),
+            (value) -> {
+                if (value != null && ((String)value).contains(",") || ((String)value).contains(" ")) {
+                    throw new IllegalArgumentException("Multiple backup provider plugins are not supported. Please provide a single plugin value.");
+                }
+                List<String> validPlugins = List.of("dummy", "veeam", "networker", "nas");
+                if (!validPlugins.contains(((String) value).toLowerCase())) {
+                    throw new IllegalArgumentException("Invalid backup provider plugin: " + value + ". Valid plugin values are: " + String.join(", ", validPlugins));
+                }
+            });
 
     ConfigKey<Long> BackupSyncPollingInterval = new ConfigKey<>("Advanced", Long.class,
             "backup.framework.sync.interval",

framework/config/src/main/java/org/apache/cloudstack/framework/config/ValidatedConfigKey.java

@@ -0,0 +1,38 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you 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.
+package org.apache.cloudstack.framework.config;
+
+import java.util.function.Consumer;
+
+public class ValidatedConfigKey<T> extends ConfigKey<String> {
+    private final Consumer<T> validator;
+
+    public ValidatedConfigKey(String category, Class<String> type, String name, String defaultValue, String description, boolean dynamic, Scope scope, String parent, Consumer<T> validator) {
+        super(category, type, name, defaultValue, description, dynamic, scope);
+        this.validator = validator;
+    }
+
+    public Consumer<T> getValidator() {
+        return validator;
+    }
+
+    public void validateValue(String value) {
+        if (validator != null) {
+            validator.accept((T) value);
+        }
+    }
+}

server/src/main/java/com/cloud/configuration/ConfigurationManagerImpl.java

@@ -107,6 +107,7 @@
 import org.apache.cloudstack.framework.config.ConfigDepot;
 import org.apache.cloudstack.framework.config.ConfigKey;
 import org.apache.cloudstack.framework.config.Configurable;
+import org.apache.cloudstack.framework.config.ValidatedConfigKey;
 import org.apache.cloudstack.framework.config.dao.ConfigurationDao;
 import org.apache.cloudstack.framework.config.dao.ConfigurationGroupDao;
 import org.apache.cloudstack.framework.config.dao.ConfigurationSubGroupDao;
@@ -716,6 +717,12 @@ public String updateConfiguration(final long userId, final String name, final St
             throw new InvalidParameterValueException(validationMsg);
         }
 
+        ConfigKey<?> configKey = _configDepot.get(name);
+        if (configKey instanceof ValidatedConfigKey) {
+            ValidatedConfigKey<?> validatedConfigKey = (ValidatedConfigKey<?>) configKey;
+            validatedConfigKey.validateValue(value);
+        }
+
         // If scope of the parameter is given then it needs to be updated in the
         // corresponding details table,
         // if scope is mentioned as global or not mentioned then it is normal