org.apache.distributedlog.client.routing.TwitterServerSetWatcher Maven / Gradle / Ivy
/**
* 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.distributedlog.client.routing;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Sets;
import com.twitter.common.net.pool.DynamicHostSet;
import com.twitter.common.zookeeper.ServerSet;
import org.apache.distributedlog.service.DLSocketAddress;
import com.twitter.thrift.Endpoint;
import com.twitter.thrift.ServiceInstance;
import java.net.InetSocketAddress;
import java.util.Set;
/**
* Twitter {@link ServerSet} based watcher.
*/
public class TwitterServerSetWatcher implements ServerSetWatcher {
private final ServerSet serverSet;
private final boolean resolvedFromName;
/**
* Construct a {@link ServerSet} based watcher.
*
* @param serverSet server set.
* @param resolvedFromName whether to resolve hosts from {@link com.twitter.finagle.Name}.
*/
public TwitterServerSetWatcher(ServerSet serverSet,
boolean resolvedFromName) {
this.serverSet = serverSet;
this.resolvedFromName = resolvedFromName;
}
/**
* Registers a monitor to receive change notices for this server set as long as this jvm process is alive.
*
* Blocks until the initial server set can be gathered and delivered to the monitor.
* The monitor will be notified if the membership set or parameters of existing members have
* changed.
*
* @param monitor the server set monitor to call back when the host set changes
* @throws MonitorException if there is a problem monitoring the host set
*/
public void watch(final ServerSetMonitor monitor)
throws MonitorException {
try {
serverSet.watch(new DynamicHostSet.HostChangeMonitor() {
@Override
public void onChange(ImmutableSet serviceInstances) {
Set dlServers = Sets.newHashSet();
for (ServiceInstance serviceInstance : serviceInstances) {
Endpoint endpoint = serviceInstance.getAdditionalEndpoints().get("thrift");
InetSocketAddress inetAddr =
new InetSocketAddress(endpoint.getHost(), endpoint.getPort());
int shardId = resolvedFromName ? -1 : serviceInstance.getShard();
DLSocketAddress address = new DLSocketAddress(shardId, inetAddr);
dlServers.add(address);
}
monitor.onChange(ImmutableSet.copyOf(dlServers));
}
});
} catch (DynamicHostSet.MonitorException me) {
throw new MonitorException("Failed to monitor server set : ", me);
}
}
}