| /** |
| * 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.hadoop.crypto.key; |
| |
| import java.io.IOException; |
| import java.net.URI; |
| import java.net.URISyntaxException; |
| import java.util.ArrayList; |
| import java.util.Iterator; |
| import java.util.List; |
| import java.util.ServiceLoader; |
| |
| import org.apache.hadoop.classification.InterfaceAudience; |
| import org.apache.hadoop.classification.InterfaceStability; |
| import org.apache.hadoop.conf.Configuration; |
| import org.apache.hadoop.fs.CommonConfigurationKeysPublic; |
| |
| /** |
| * A factory to create a list of KeyProvider based on the path given in a |
| * Configuration. It uses a service loader interface to find the available |
| * KeyProviders and create them based on the list of URIs. |
| */ |
| @InterfaceAudience.Public |
| @InterfaceStability.Unstable |
| public abstract class KeyProviderFactory { |
| public static final String KEY_PROVIDER_PATH = |
| CommonConfigurationKeysPublic.HADOOP_SECURITY_KEY_PROVIDER_PATH; |
| |
| public abstract KeyProvider createProvider(URI providerName, |
| Configuration conf |
| ) throws IOException; |
| |
| private static final ServiceLoader<KeyProviderFactory> serviceLoader = |
| ServiceLoader.load(KeyProviderFactory.class, |
| KeyProviderFactory.class.getClassLoader()); |
| |
| // Iterate through the serviceLoader to avoid lazy loading. |
| // Lazy loading would require synchronization in concurrent use cases. |
| static { |
| Iterator<KeyProviderFactory> iterServices = serviceLoader.iterator(); |
| while (iterServices.hasNext()) { |
| iterServices.next(); |
| } |
| } |
| |
| public static List<KeyProvider> getProviders(Configuration conf |
| ) throws IOException { |
| List<KeyProvider> result = new ArrayList<KeyProvider>(); |
| for(String path: conf.getStringCollection(KEY_PROVIDER_PATH)) { |
| try { |
| URI uri = new URI(path); |
| KeyProvider kp = get(uri, conf); |
| if (kp != null) { |
| result.add(kp); |
| } else { |
| throw new IOException("No KeyProviderFactory for " + uri + " in " + |
| KEY_PROVIDER_PATH); |
| } |
| } catch (URISyntaxException error) { |
| throw new IOException("Bad configuration of " + KEY_PROVIDER_PATH + |
| " at " + path, error); |
| } |
| } |
| return result; |
| } |
| |
| /** |
| * Create a KeyProvider based on a provided URI. |
| * |
| * @param uri key provider URI |
| * @param conf configuration to initialize the key provider |
| * @return the key provider for the specified URI, or <code>NULL</code> if |
| * a provider for the specified URI scheme could not be found. |
| * @throws IOException thrown if the provider failed to initialize. |
| */ |
| public static KeyProvider get(URI uri, Configuration conf) |
| throws IOException { |
| KeyProvider kp = null; |
| for (KeyProviderFactory factory : serviceLoader) { |
| kp = factory.createProvider(uri, conf); |
| if (kp != null) { |
| break; |
| } |
| } |
| return kp; |
| } |
| |
| } |