RogPodge commented on a change in pull request #275: KNOX-2253 Add support to handle Livy server redirects URL: https://github.com/apache/knox/pull/275#discussion_r394718586
########## File path: gateway-service-livy/src/main/java/org/apache/knox/gateway/livy/LivyHaDispatch.java ########## @@ -0,0 +1,156 @@ +/* + * 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.knox.gateway.livy; + +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 org.apache.knox.gateway.ha.dispatch.DefaultHaDispatch; +import org.apache.knox.gateway.filter.AbstractGatewayFilter; +import org.apache.knox.gateway.i18n.messages.MessagesFactory; +import org.apache.knox.gateway.livy.i18n.RMMessages; + +import javax.servlet.http.HttpServletRequest; +import javax.servlet.http.HttpServletResponse; +import java.io.ByteArrayOutputStream; +import java.io.IOException; +import java.net.URI; +import java.nio.charset.StandardCharsets; +import java.util.concurrent.atomic.AtomicInteger; + +public class LivyHaDispatch extends DefaultHaDispatch { + private static final String FAILOVER_COUNTER_ATTRIBUTE = "dispatch.ha.failover.counter"; + private static final String LOCATION = "Location"; + private static final RMMessages LOG = MessagesFactory.get(RMMessages.class); + private HttpResponse inboundResponse = null; + + + public LivyHaDispatch() { + setServiceRole("LIVYSERVER"); + } + + /** + * + * @return HttpReponse used for unit testing so we + * can inject inboundResponse before calling executeRequest method + */ + private HttpResponse getInboundResponse() { + HttpResponse response = this.inboundResponse; + this.setInboundResponse(null); + return response; + } + + void setInboundResponse(HttpResponse inboundResponse) { + this.inboundResponse = inboundResponse; + } + + @Override + protected void executeRequest(HttpUriRequest outboundRequest, HttpServletRequest inboundRequest, HttpServletResponse outboundResponse) throws IOException { + HttpResponse inboundResponse = this.getInboundResponse(); + try { + if( this.getInboundResponse() == null ) { + inboundResponse = executeOutboundRequest(outboundRequest); + } + writeOutboundResponse(outboundRequest, inboundRequest, outboundResponse, inboundResponse); + } catch (StandbyException e) { + LOG.errorReceivedFromStandbyNode(e); + failoverRequest(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 { + int status = inboundResponse.getStatusLine().getStatusCode(); + if ( status == 403 || status == 307) { + BufferedHttpEntity entity = new BufferedHttpEntity(inboundResponse.getEntity()); + inboundResponse.setEntity(entity); + ByteArrayOutputStream outputStream = new ByteArrayOutputStream(); + inboundResponse.getEntity().writeTo(outputStream); + String body = new String(outputStream.toByteArray(), StandardCharsets.UTF_8); + if (body.contains("This is a standby Livy Instance")) { + throw new StandbyException(); + } + } + super.writeOutboundResponse(outboundRequest, inboundRequest, outboundResponse, inboundResponse); + } + + @Override + protected void failoverRequest(HttpUriRequest outboundRequest, HttpServletRequest inboundRequest, HttpServletResponse outboundResponse, HttpResponse inboundResponse, Exception exception) throws IOException { + LOG.failingOverRequest(outboundRequest.getURI().toString()); + URI uri; + String outboundURIs; + AtomicInteger counter = (AtomicInteger) inboundRequest.getAttribute(FAILOVER_COUNTER_ATTRIBUTE); + if (counter == null) { + counter = new AtomicInteger(0); + } + inboundRequest.setAttribute(FAILOVER_COUNTER_ATTRIBUTE, counter); + outboundURIs = outboundRequest.getURI().toString(); + + if (counter.incrementAndGet() <= getMaxFailoverAttempts()) { + //null out target url so that rewriters run again + inboundRequest.setAttribute(AbstractGatewayFilter.TARGET_REQUEST_URL_ATTRIBUTE_NAME, null); + + uri = getUriFromInbound(inboundRequest, inboundResponse, outboundURIs); + ((HttpRequestBase) outboundRequest).setURI(uri); + if (getFailoverSleep() > 0) { + try { + Thread.sleep(getFailoverSleep()); + } catch (InterruptedException e) { + LOG.failoverSleepFailed(getServiceRole(), e); + } + } + executeRequest(outboundRequest, inboundRequest, outboundResponse); + } else { + LOG.maxFailoverAttemptsReached(getMaxFailoverAttempts(), getServiceRole()); + if (inboundResponse != null) { + writeOutboundResponse(outboundRequest, inboundRequest, outboundResponse, inboundResponse); + } else { + throw new IOException(exception); + } + } + } Review comment: refactored to inherit from DefaultHADispatch ---------------------------------------------------------------- This is an automated message from the Apache Git Service. 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