| /* |
| * 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.tephra.distributed; |
| |
| import com.google.common.base.Throwables; |
| import org.apache.hadoop.conf.Configuration; |
| import org.apache.tephra.TxConstants; |
| import org.apache.thrift.TException; |
| import org.apache.twill.discovery.DiscoveryServiceClient; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| import java.util.concurrent.TimeUnit; |
| import java.util.concurrent.TimeoutException; |
| |
| /** |
| * This is an tx client provider that uses a bounded size pool of connections. |
| */ |
| public class PooledClientProvider extends AbstractClientProvider { |
| |
| private static final Logger LOG = |
| LoggerFactory.getLogger(PooledClientProvider.class); |
| |
| // we will use this as a pool of tx clients |
| class TxClientPool extends ElasticPool<TransactionServiceThriftClient, TException> { |
| TxClientPool(int sizeLimit) { |
| super(sizeLimit); |
| } |
| |
| @Override |
| protected TransactionServiceThriftClient create() throws TException { |
| return newClient(); |
| } |
| |
| @Override |
| protected boolean recycle(TransactionServiceThriftClient client) { |
| if (!client.isValid()) { |
| client.close(); |
| return false; |
| } |
| return true; |
| } |
| } |
| |
| // we will use this as a pool of tx clients |
| private volatile TxClientPool clients; |
| |
| // the limit for the number of active clients |
| private int maxClients; |
| // timeout, for obtaining a client |
| private long obtainClientTimeoutMs; |
| |
| public PooledClientProvider(Configuration conf, DiscoveryServiceClient discoveryServiceClient) { |
| super(conf, discoveryServiceClient); |
| } |
| |
| private void initializePool() throws TException { |
| // initialize the super class (needed for service discovery) |
| super.initialize(); |
| |
| // create a (empty) pool of tx clients |
| maxClients = configuration.getInt(TxConstants.Service.CFG_DATA_TX_CLIENT_COUNT, |
| TxConstants.Service.DEFAULT_DATA_TX_CLIENT_COUNT); |
| if (maxClients < 1) { |
| LOG.warn("Configuration of " + TxConstants.Service.CFG_DATA_TX_CLIENT_COUNT + |
| " is invalid: value is " + maxClients + " but must be at least 1. " + |
| "Using 1 as a fallback. "); |
| maxClients = 1; |
| } |
| |
| obtainClientTimeoutMs = |
| configuration.getLong(TxConstants.Service.CFG_DATA_TX_CLIENT_OBTAIN_TIMEOUT_MS, |
| TxConstants.Service.DEFAULT_DATA_TX_CLIENT_OBTAIN_TIMEOUT_MS); |
| if (obtainClientTimeoutMs < 0) { |
| LOG.warn("Configuration of " + TxConstants.Service.CFG_DATA_TX_CLIENT_COUNT + |
| " is invalid: value is " + obtainClientTimeoutMs + " but must be at least 0. " + |
| "Using 0 as a fallback. "); |
| obtainClientTimeoutMs = 0; |
| } |
| this.clients = new TxClientPool(maxClients); |
| } |
| |
| @Override |
| public CloseableThriftClient getCloseableClient() throws TException, TimeoutException, InterruptedException { |
| TransactionServiceThriftClient client = getClientPool().obtain(obtainClientTimeoutMs, TimeUnit.MILLISECONDS); |
| return new CloseableThriftClient(this, client); |
| } |
| |
| @Override |
| public void returnClient(TransactionServiceThriftClient client) { |
| getClientPool().release(client); |
| } |
| |
| @Override |
| public String toString() { |
| return "Elastic pool of size " + this.maxClients + |
| ", with timeout (in milliseconds): " + this.obtainClientTimeoutMs; |
| } |
| |
| private TxClientPool getClientPool() { |
| if (clients != null) { |
| return clients; |
| } |
| |
| synchronized (this) { |
| if (clients == null) { |
| try { |
| initializePool(); |
| } catch (TException e) { |
| LOG.error("Failed to initialize Tx client provider", e); |
| throw Throwables.propagate(e); |
| } |
| } |
| } |
| return clients; |
| } |
| } |