/**
* 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
* <p/>
* http://www.apache.org/licenses/LICENSE-2.0
* <p/>
* 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.hadoop.gateway.hdfs.dispatch;
import org.apache.hadoop.gateway.filter.AbstractGatewayFilter;
import org.apache.hadoop.gateway.ha.provider.HaProvider;
import org.apache.hadoop.gateway.ha.provider.HaServiceConfig;
import org.apache.hadoop.gateway.ha.provider.HaServletContextListener;
import org.apache.hadoop.gateway.hdfs.i18n.WebHdfsMessages;
import org.apache.hadoop.gateway.i18n.messages.MessagesFactory;
import org.apache.http.HttpResponse;
import org.apache.http.client.methods.HttpRequestBase;
import org.apache.http.client.methods.HttpUriRequest;
import org.apache.http.entity.BufferedHttpEntity;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.net.URI;
import java.util.concurrent.atomic.AtomicInteger;
public class WebHdfsHaHttpClientDispatch extends HdfsDispatch {
private static final String FAILOVER_COUNTER_ATTRIBUTE = "dispatch.ha.failover.counter";
private static final String RETRY_COUNTER_ATTRIBUTE = "dispatch.ha.retry.counter";
public static final String RESOURCE_ROLE_ATTRIBUTE = "resource.role";
private static final WebHdfsMessages LOG = MessagesFactory.get(WebHdfsMessages.class);
private int maxFailoverAttempts;
private int failoverSleep;
private int maxRetryAttempts;
private int retrySleep;
private String resourceRole;
private HaProvider haProvider;
/**
* @throws ServletException
*/
public WebHdfsHaHttpClientDispatch() throws ServletException {
super();
}
@Override
public void init(FilterConfig filterConfig) throws ServletException {
super.init(filterConfig);
resourceRole = filterConfig.getInitParameter(RESOURCE_ROLE_ATTRIBUTE);
LOG.initializingForResourceRole(resourceRole);
haProvider = HaServletContextListener.getHaProvider(filterConfig.getServletContext());
HaServiceConfig serviceConfig = haProvider.getHaDescriptor().getServiceConfig(resourceRole);
maxFailoverAttempts = serviceConfig.getMaxFailoverAttempts();
failoverSleep = serviceConfig.getFailoverSleep();
maxRetryAttempts = serviceConfig.getMaxRetryAttempts();
retrySleep = serviceConfig.getRetrySleep();
}
@Override
protected void executeRequest(HttpUriRequest outboundRequest, HttpServletRequest inboundRequest, HttpServletResponse outboundResponse) throws IOException {
HttpResponse inboundResponse = null;
try {
inboundResponse = executeOutboundRequest(outboundRequest);
writeOutboundResponse(outboundRequest, inboundRequest, outboundResponse, inboundResponse);
} catch (StandbyException e) {
LOG.errorReceivedFromStandbyNode(e);
failoverRequest(outboundRequest, inboundRequest, outboundResponse, inboundResponse, e);
} catch (SafeModeException e) {
LOG.errorReceivedFromSafeModeNode(e);
retryRequest(outboundRequest, inboundRequest, outboundResponse, inboundResponse, e);
} catch (IOException e) {
LOG.errorConnectingToServer(outboundRequest.getURI().toString(), e);
failoverRequest(outboundRequest, inboundRequest, outboundResponse, inboundResponse, e);
}
}
/**
* Checks for specific outbound response codes/content to trigger a retry or failover
*/
@Override
protected void writeOutboundResponse(HttpUriRequest outboundRequest, HttpServletRequest inboundRequest, HttpServletResponse outboundResponse, HttpResponse inboundResponse) throws IOException {
if (inboundResponse.getStatusLine().getStatusCode() == 403) {
BufferedHttpEntity entity = new BufferedHttpEntity(inboundResponse.getEntity());
inboundResponse.setEntity(entity);
ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
inboundResponse.getEntity().writeTo(outputStream);
String body = new String(outputStream.toByteArray());
if (body.contains("StandbyException")) {
throw new StandbyException();
}
if (body.contains("SafeModeException") || body.contains("RetriableException")) {
throw new SafeModeException();
}
}
super.writeOutboundResponse(outboundRequest, inboundRequest, outboundResponse, inboundResponse);
}
private void failoverRequest(HttpUriRequest outboundRequest, HttpServletRequest inboundRequest, HttpServletResponse outboundResponse, HttpResponse inboundResponse, Exception exception) throws IOException {
LOG.failingOverRequest(outboundRequest.getURI().toString());
AtomicInteger counter = (AtomicInteger) inboundRequest.getAttribute(FAILOVER_COUNTER_ATTRIBUTE);
if (counter == null) {
counter = new AtomicInteger(0);
}
inboundRequest.setAttribute(FAILOVER_COUNTER_ATTRIBUTE, counter);
if (counter.incrementAndGet() <= maxFailoverAttempts) {
haProvider.markFailedURL(resourceRole, outboundRequest.getURI().toString());
//null out target url so that rewriters run again
inboundRequest.setAttribute(AbstractGatewayFilter.TARGET_REQUEST_URL_ATTRIBUTE_NAME, null);
URI uri = getDispatchUrl(inboundRequest);
((HttpRequestBase) outboundRequest).setURI(uri);
if (failoverSleep > 0) {
try {
Thread.sleep(failoverSleep);
} catch (InterruptedException e) {
LOG.failoverSleepFailed(resourceRole, e);
}
}
executeRequest(outboundRequest, inboundRequest, outboundResponse);
} else {
LOG.maxFailoverAttemptsReached(maxFailoverAttempts, resourceRole);
if (inboundResponse != null) {
writeOutboundResponse(outboundRequest, inboundRequest, outboundResponse, inboundResponse);
} else {
throw new IOException(exception);
}
}
}
private void retryRequest(HttpUriRequest outboundRequest, HttpServletRequest inboundRequest, HttpServletResponse outboundResponse, HttpResponse inboundResponse, Exception exception) throws IOException {
LOG.retryingRequest(outboundRequest.getURI().toString());
AtomicInteger counter = (AtomicInteger) inboundRequest.getAttribute(RETRY_COUNTER_ATTRIBUTE);
if (counter == null) {
counter = new AtomicInteger(0);
}
inboundRequest.setAttribute(RETRY_COUNTER_ATTRIBUTE, counter);
if (counter.incrementAndGet() <= maxRetryAttempts) {
if (retrySleep > 0) {
try {
Thread.sleep(retrySleep);
} catch (InterruptedException e) {
LOG.retrySleepFailed(resourceRole, e);
}
}
executeRequest(outboundRequest, inboundRequest, outboundResponse);
} else {
LOG.maxRetryAttemptsReached(maxRetryAttempts, resourceRole, outboundRequest.getURI().toString());
if (inboundResponse != null) {
writeOutboundResponse(outboundRequest, inboundRequest, outboundResponse, inboundResponse);
} else {
throw new IOException(exception);
}
}
}
}