Java tutorial
/* * Copyright 2014 Cask Data, Inc. * * Licensed 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 co.cask.cdap.common.twill; import co.cask.cdap.common.conf.CConfiguration; import co.cask.cdap.common.conf.Constants; import co.cask.cdap.proto.Containers; import co.cask.cdap.proto.SystemServiceLiveInfo; import com.google.common.base.Preconditions; import com.google.common.util.concurrent.Futures; import org.apache.twill.api.ResourceReport; import org.apache.twill.api.TwillController; import org.apache.twill.api.TwillRunResources; import org.apache.twill.api.TwillRunnerService; import org.apache.twill.discovery.Discoverable; import org.apache.twill.discovery.DiscoveryServiceClient; import org.jboss.netty.handler.codec.http.HttpResponseStatus; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import java.net.HttpURLConnection; import java.net.SocketTimeoutException; import java.net.URL; import java.util.Collection; import java.util.concurrent.TimeUnit; /** * Abstract class that can be extended by individual CDAP Services to implement their management methods. */ public abstract class AbstractDistributedMasterServiceManager implements MasterServiceManager { private static final Logger LOG = LoggerFactory.getLogger(AbstractDistributedMasterServiceManager.class); private static final long SERVICE_PING_RESPONSE_TIMEOUT = TimeUnit.MILLISECONDS.convert(1, TimeUnit.SECONDS); protected final long discoveryTimeout; protected CConfiguration cConf; protected TwillRunnerService twillRunnerService; protected String serviceName; protected DiscoveryServiceClient discoveryServiceClient; public AbstractDistributedMasterServiceManager(CConfiguration cConf, String serviceName, TwillRunnerService twillRunnerService, DiscoveryServiceClient discoveryServiceClient) { this.cConf = cConf; this.serviceName = serviceName; this.twillRunnerService = twillRunnerService; this.discoveryTimeout = cConf.getLong(Constants.Monitor.DISCOVERY_TIMEOUT_SECONDS); this.discoveryServiceClient = discoveryServiceClient; } @Override public SystemServiceLiveInfo getLiveInfo() { SystemServiceLiveInfo.Builder builder = SystemServiceLiveInfo.builder(); Iterable<TwillController> twillControllerList = twillRunnerService .lookup(Constants.Service.MASTER_SERVICES); if (twillControllerList == null) { return builder.build(); } for (TwillController twillController : twillControllerList) { if (twillController.getResourceReport() == null) { continue; } ResourceReport resourceReport = twillController.getResourceReport(); Collection<TwillRunResources> runResources = resourceReport.getResources().get(serviceName); for (TwillRunResources resources : runResources) { Containers.ContainerInfo containerInfo = new Containers.ContainerInfo( Containers.ContainerType.SYSTEM_SERVICE, serviceName, resources.getInstanceId(), resources.getContainerId(), resources.getHost(), resources.getMemoryMB(), resources.getVirtualCores(), resources.getDebugPort()); builder.addContainer(containerInfo); } } return builder.build(); } @Override public int getInstances() { Iterable<TwillController> twillControllerList = twillRunnerService .lookup(Constants.Service.MASTER_SERVICES); int instances = 0; if (twillControllerList != null) { for (TwillController twillController : twillControllerList) { if (twillController.getResourceReport() != null) { instances = twillController.getResourceReport().getRunnableResources(serviceName).size(); } } } return instances; } public boolean isServiceEnabled() { // By default all the services are enabled. extending classes can override if the behavior should be different. return true; } @Override public boolean setInstances(int instanceCount) { Preconditions.checkArgument(instanceCount > 0); try { Iterable<TwillController> twillControllerList = twillRunnerService .lookup(Constants.Service.MASTER_SERVICES); if (twillControllerList != null) { for (TwillController twillController : twillControllerList) { twillController.changeInstances(serviceName, instanceCount).get(); } } return true; } catch (Throwable t) { LOG.error("Could not change service instance of {} : {}", serviceName, t.getMessage(), t); return false; } } @Override public int getMinInstances() { return 1; } @Override public boolean canCheckStatus() { return true; } @Override public boolean isLogAvailable() { return true; } @Override public boolean isServiceAvailable() { try { Iterable<Discoverable> discoverables = this.discoveryServiceClient.discover(serviceName); for (Discoverable discoverable : discoverables) { //Ping the discovered service to check its status. String url = String.format("http://%s:%d/ping", discoverable.getSocketAddress().getHostName(), discoverable.getSocketAddress().getPort()); if (checkGetStatus(url).equals(HttpResponseStatus.OK)) { return true; } } return false; } catch (IllegalArgumentException e) { return false; } catch (Exception e) { LOG.warn("Unable to ping {} : Reason : {}", serviceName, e.getMessage()); return false; } } protected final HttpResponseStatus checkGetStatus(String url) throws Exception { HttpURLConnection httpConn = null; try { httpConn = (HttpURLConnection) new URL(url).openConnection(); httpConn.setConnectTimeout((int) SERVICE_PING_RESPONSE_TIMEOUT); httpConn.setReadTimeout((int) SERVICE_PING_RESPONSE_TIMEOUT); return (HttpResponseStatus.valueOf(httpConn.getResponseCode())); } catch (SocketTimeoutException e) { return HttpResponseStatus.NOT_FOUND; } finally { if (httpConn != null) { httpConn.disconnect(); } } } @Override public void restartAllInstances() { Iterable<TwillController> twillControllers = twillRunnerService.lookup(Constants.Service.MASTER_SERVICES); for (TwillController twillController : twillControllers) { // Call restart instances Futures.getUnchecked(twillController.restartAllInstances(serviceName)); } } @Override public void restartInstances(int instanceId, int... moreInstanceIds) { Iterable<TwillController> twillControllers = twillRunnerService.lookup(Constants.Service.MASTER_SERVICES); for (TwillController twillController : twillControllers) { // Call restart instances Futures.getUnchecked(twillController.restartInstances(serviceName, instanceId, moreInstanceIds)); } } }