common/openstack/src/main/java/org/jclouds/openstack/config/OpenStackAuthenticationModule.java

/**
 * Licensed to jclouds, Inc. (jclouds) under one or more
 * contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  jclouds 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.jclouds.openstack.config;

import java.util.Date;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;

import javax.inject.Inject;
import javax.inject.Named;
import javax.inject.Singleton;

import org.jclouds.Constants;
import org.jclouds.concurrent.RetryOnTimeOutExceptionSupplier;
import org.jclouds.date.TimeStamp;
import org.jclouds.http.RequiresHttp;
import org.jclouds.openstack.Authentication;
import org.jclouds.openstack.OpenStackAuthAsyncClient;
import org.jclouds.openstack.OpenStackAuthAsyncClient.AuthenticationResponse;
import org.jclouds.rest.AsyncClientFactory;

import com.google.common.base.Supplier;
import com.google.common.base.Suppliers;
import com.google.common.base.Throwables;
import com.google.common.cache.CacheBuilder;
import com.google.common.cache.CacheLoader;
import com.google.common.cache.LoadingCache;
import com.google.common.util.concurrent.UncheckedExecutionException;
import com.google.inject.AbstractModule;
import com.google.inject.Provides;

/**
 * Configures the Rackspace authentication service connection, including logging and http transport.
 * 
 * @author Adrian Cole
 */
@RequiresHttp
public class OpenStackAuthenticationModule extends AbstractModule {

   @Override
   protected void configure() {
   }

   /**
    * borrowing concurrency code to ensure that caching takes place properly
    */
   @Provides
   @Singleton
   @Authentication
   protected Supplier<String> provideAuthenticationTokenCache(final Supplier<AuthenticationResponse> supplier)
            throws InterruptedException, ExecutionException, TimeoutException {
      return new Supplier<String>() {
         public String get() {
            return supplier.get().getAuthToken();
         }
      };
   }

   @Singleton
   public static class GetAuthenticationResponse implements Supplier<AuthenticationResponse> {
      protected final OpenStackAuthAsyncClient client;
      protected final String user;
      protected final String key;

      @Inject
      public GetAuthenticationResponse(AsyncClientFactory factory, @Named(Constants.PROPERTY_IDENTITY) String user,
               @Named(Constants.PROPERTY_CREDENTIAL) String key) {
         this.client = factory.create(OpenStackAuthAsyncClient.class);
         this.user = user;
         this.key = key;
      }

      @Override
      public AuthenticationResponse get() {
         try {
            Future<AuthenticationResponse> response = authenticate();
            return response.get(30, TimeUnit.SECONDS);
         } catch (Exception e) {
            Throwables.propagate(e);
            assert false : e;
            return null;
         }
      }

      protected Future<AuthenticationResponse> authenticate() {
         return client.authenticate(user, key);
      }

   }

   @Provides
   @Singleton
   public LoadingCache<String,AuthenticationResponse> provideAuthenticationResponseCache2(
            final GetAuthenticationResponse getAuthenticationResponse) {
      
      final RetryOnTimeOutExceptionSupplier<AuthenticationResponse> delegate = 
               new RetryOnTimeOutExceptionSupplier<AuthenticationResponse>(getAuthenticationResponse);

      CacheLoader<String, AuthenticationResponse> cacheLoader = new CacheLoader<String, AuthenticationResponse>() {
         @Override
         public AuthenticationResponse load(String key) throws Exception {
            return delegate.get();
         }
      };
      
      LoadingCache<String, AuthenticationResponse> cache = CacheBuilder.newBuilder().expireAfterWrite(23, TimeUnit.HOURS)
               .build(cacheLoader);
      
      return cache;
   }

   @Provides
   @Singleton
   protected Supplier<AuthenticationResponse> provideAuthenticationResponseSupplier(
            final LoadingCache<String,AuthenticationResponse> cache) {
      return new Supplier<AuthenticationResponse>() {
         @Override
         public AuthenticationResponse get() {
            try {
               return cache.get("key");
            } catch (UncheckedExecutionException e) {
               throw Throwables.propagate(e.getCause());
            } catch (ExecutionException e) {
               throw Throwables.propagate(e.getCause());
            }
         }
      };
   }

   @Provides
   @Singleton
   @TimeStamp
   protected Supplier<Date> provideCacheBusterDate() {
      return Suppliers.memoizeWithExpiration(new Supplier<Date>() {
         public Date get() {
            return new Date();
         }
      }, 1, TimeUnit.SECONDS);
   }

   @Provides
   @Singleton
   protected AuthenticationResponse provideAuthenticationResponse(Supplier<AuthenticationResponse> supplier)
            throws InterruptedException, ExecutionException, TimeoutException {
      return supplier.get();
   }

}