Java tutorial
/** * 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 com.twitter.distributedlog.service.balancer; import com.google.common.base.Optional; import com.google.common.util.concurrent.RateLimiter; import com.twitter.distributedlog.client.monitor.MonitorServiceClient; import com.twitter.distributedlog.service.DLSocketAddress; import com.twitter.distributedlog.service.DistributedLogClient; import com.twitter.distributedlog.service.DistributedLogCluster.DLServer; import com.twitter.distributedlog.service.DistributedLogServerTestCase; import com.twitter.util.Await; import org.apache.commons.lang3.tuple.Pair; import org.junit.After; import org.junit.Before; import org.junit.Ignore; import org.junit.Test; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import java.nio.ByteBuffer; import java.util.ArrayList; import java.util.HashSet; import java.util.List; import java.util.Set; import static com.google.common.base.Charsets.UTF_8; import static org.junit.Assert.*; public class TestClusterBalancer extends DistributedLogServerTestCase { static final Logger logger = LoggerFactory.getLogger(TestClusterBalancer.class); private final int numServers = 5; private final List<DLServer> cluster; private DLClient client; public TestClusterBalancer() { this.cluster = new ArrayList<DLServer>(); } @Before @Override public void setup() throws Exception { super.setup(); int initPort = 9001; for (int i = 0; i < numServers; i++) { cluster.add(createDistributedLogServer(initPort + i)); } client = createDistributedLogClient("cluster_client"); } @After @Override public void teardown() throws Exception { super.teardown(); if (null != client) { client.shutdown(); } for (DLServer server : cluster) { server.shutdown(); } } private void initStreams(String namePrefix) { logger.info("Init streams with prefix {}", namePrefix); // Stream Distribution: 5, 4, 3, 2, 1 initStreams(namePrefix, 5, 1, 0); initStreams(namePrefix, 4, 6, 1); initStreams(namePrefix, 3, 10, 2); initStreams(namePrefix, 2, 13, 3); initStreams(namePrefix, 1, 15, 4); } private void initStreams(String namePrefix, int numStreams, int streamId, int proxyId) { for (int i = 0; i < numStreams; i++) { String name = namePrefix + (streamId++); client.routingService.addHost(name, cluster.get(proxyId).getAddress()); } } private void writeStreams(String namePrefix) throws Exception { logger.info("Write streams with prefix {}", namePrefix); writeStreams(namePrefix, 5, 1); writeStreams(namePrefix, 4, 6); writeStreams(namePrefix, 3, 10); writeStreams(namePrefix, 2, 13); writeStreams(namePrefix, 1, 15); } private void writeStreams(String namePrefix, int numStreams, int streamId) throws Exception { for (int i = 0; i < numStreams; i++) { String name = namePrefix + (streamId++); try { Await.result(((DistributedLogClient) client.dlClient).write(name, ByteBuffer.wrap(name.getBytes(UTF_8)))); } catch (Exception e) { logger.error("Error writing stream {} : ", name, e); throw e; } } } private void validateStreams(String namePrefix) throws Exception { logger.info("Validate streams with prefix {}", namePrefix); validateStreams(namePrefix, 5, 1, 0); validateStreams(namePrefix, 4, 6, 1); validateStreams(namePrefix, 3, 10, 2); validateStreams(namePrefix, 2, 13, 3); validateStreams(namePrefix, 1, 15, 4); } private void validateStreams(String namePrefix, int numStreams, int streamId, int proxyIdx) { Set<String> expectedStreams = new HashSet<String>(); for (int i = 0; i < numStreams; i++) { expectedStreams.add(namePrefix + (streamId++)); } checkStreams(expectedStreams, cluster.get(proxyIdx)); } @Ignore @Test(timeout = 60000) public void testBalanceAll() throws Exception { String namePrefix = "clusterbalancer-balance-all-"; initStreams(namePrefix); writeStreams(namePrefix); validateStreams(namePrefix); Optional<RateLimiter> rateLimiter = Optional.absent(); Balancer balancer = new ClusterBalancer(client.dlClientBuilder, Pair.of((DistributedLogClient) client.dlClient, (MonitorServiceClient) client.dlClient)); logger.info("Rebalancing from 'unknown' target"); try { balancer.balanceAll("unknown", 10, rateLimiter); fail("Should fail on balanceAll from 'unknown' target."); } catch (IllegalArgumentException iae) { // expected } validateStreams(namePrefix); logger.info("Rebalancing from 'unexisted' host"); String addr = DLSocketAddress.toString(DLSocketAddress.getSocketAddress(9999)); balancer.balanceAll(addr, 10, rateLimiter); validateStreams(namePrefix); addr = DLSocketAddress.toString(cluster.get(0).getAddress()); logger.info("Rebalancing from host {}.", addr); balancer.balanceAll(addr, 10, rateLimiter); checkStreams(0, cluster.get(0)); checkStreams(4, cluster.get(1)); checkStreams(3, cluster.get(2)); checkStreams(4, cluster.get(3)); checkStreams(4, cluster.get(4)); addr = DLSocketAddress.toString(cluster.get(2).getAddress()); logger.info("Rebalancing from host {}.", addr); balancer.balanceAll(addr, 10, rateLimiter); checkStreams(3, cluster.get(0)); checkStreams(4, cluster.get(1)); checkStreams(0, cluster.get(2)); checkStreams(4, cluster.get(3)); checkStreams(4, cluster.get(4)); logger.info("Rebalancing the cluster"); balancer.balance(0, 0.0f, 10, rateLimiter); for (int i = 0; i < 5; i++) { checkStreams(3, cluster.get(i)); } } }