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 org.apache.pulsar.broker.lookup; import static com.google.common.base.Preconditions.checkNotNull; import static org.apache.pulsar.common.api.Commands.newLookupErrorResponse; import static org.apache.pulsar.common.api.Commands.newLookupResponse; import io.netty.buffer.ByteBuf; import java.net.URI; import java.net.URISyntaxException; import java.util.Optional; import java.util.concurrent.CompletableFuture; import java.util.concurrent.CompletionException; import javax.ws.rs.Encoded; import javax.ws.rs.WebApplicationException; import javax.ws.rs.container.AsyncResponse; import javax.ws.rs.core.Response; import org.apache.commons.lang3.StringUtils; import org.apache.pulsar.broker.PulsarService; import org.apache.pulsar.broker.authentication.AuthenticationDataSource; import org.apache.pulsar.broker.web.PulsarWebResource; import org.apache.pulsar.broker.web.RestException; import org.apache.pulsar.common.api.proto.PulsarApi.CommandLookupTopicResponse.LookupType; import org.apache.pulsar.common.api.proto.PulsarApi.ServerError; import org.apache.pulsar.common.lookup.data.LookupData; import org.apache.pulsar.common.naming.NamespaceBundle; import org.apache.pulsar.common.naming.TopicDomain; import org.apache.pulsar.common.naming.TopicName; import org.apache.pulsar.common.util.Codec; import org.slf4j.Logger; import org.slf4j.LoggerFactory; public class TopicLookupBase extends PulsarWebResource { private static final String LOOKUP_PATH_V1 = "/lookup/v2/destination/"; private static final String LOOKUP_PATH_V2 = "/lookup/v2/topic/"; protected void internalLookupTopicAsync(TopicName topicName, boolean authoritative, AsyncResponse asyncResponse) { if (!pulsar().getBrokerService().getLookupRequestSemaphore().tryAcquire()) { log.warn("No broker was found available for topic {}", topicName); asyncResponse.resume(new WebApplicationException(Response.Status.SERVICE_UNAVAILABLE)); return; } try { validateClusterOwnership(topicName.getCluster()); checkConnect(topicName); validateGlobalNamespaceOwnership(topicName.getNamespaceObject()); } catch (WebApplicationException we) { // Validation checks failed log.error("Validation check failed: {}", we.getMessage()); completeLookupResponseExceptionally(asyncResponse, we); return; } catch (Throwable t) { // Validation checks failed with unknown error log.error("Validation check failed: {}", t.getMessage(), t); completeLookupResponseExceptionally(asyncResponse, new RestException(t)); return; } CompletableFuture<Optional<LookupResult>> lookupFuture = pulsar().getNamespaceService() .getBrokerServiceUrlAsync(topicName, authoritative); lookupFuture.thenAccept(optionalResult -> { if (optionalResult == null || !optionalResult.isPresent()) { log.warn("No broker was found available for topic {}", topicName); completeLookupResponseExceptionally(asyncResponse, new WebApplicationException(Response.Status.SERVICE_UNAVAILABLE)); return; } LookupResult result = optionalResult.get(); // We have found either a broker that owns the topic, or a broker to which we should redirect the client to if (result.isRedirect()) { boolean newAuthoritative = this.isLeaderBroker(); URI redirect; try { String redirectUrl = isRequestHttps() ? result.getLookupData().getHttpUrlTls() : result.getLookupData().getHttpUrl(); checkNotNull(redirectUrl, "Redirected cluster's service url is not configured"); String lookupPath = topicName.isV2() ? LOOKUP_PATH_V2 : LOOKUP_PATH_V1; redirect = new URI(String.format("%s%s%s?authoritative=%s", redirectUrl, lookupPath, topicName.getLookupName(), newAuthoritative)); } catch (URISyntaxException | NullPointerException e) { log.error("Error in preparing redirect url for {}: {}", topicName, e.getMessage(), e); completeLookupResponseExceptionally(asyncResponse, e); return; } if (log.isDebugEnabled()) { log.debug("Redirect lookup for topic {} to {}", topicName, redirect); } completeLookupResponseExceptionally(asyncResponse, new WebApplicationException(Response.temporaryRedirect(redirect).build())); } else { // Found broker owning the topic if (log.isDebugEnabled()) { log.debug("Lookup succeeded for topic {} -- broker: {}", topicName, result.getLookupData()); } completeLookupResponseSuccessfully(asyncResponse, result.getLookupData()); } }).exceptionally(exception -> { log.warn("Failed to lookup broker for topic {}: {}", topicName, exception.getMessage(), exception); completeLookupResponseExceptionally(asyncResponse, exception); return null; }); } protected String internalGetNamespaceBundle(TopicName topicName) { validateSuperUserAccess(); try { NamespaceBundle bundle = pulsar().getNamespaceService().getBundle(topicName); return bundle.getBundleRange(); } catch (Exception e) { log.error("[{}] Failed to get namespace bundle for {}", clientAppId(), topicName, e); throw new RestException(e); } } /** * * Lookup broker-service address for a given namespace-bundle which contains given topic. * * a. Returns broker-address if namespace-bundle is already owned by any broker b. If current-broker receives * lookup-request and if it's not a leader then current broker redirects request to leader by returning * leader-service address. c. If current-broker is leader then it finds out least-loaded broker to own namespace * bundle and redirects request by returning least-loaded broker. d. If current-broker receives request to own the * namespace-bundle then it owns a bundle and returns success(connect) response to client. * * @param pulsarService * @param topicName * @param authoritative * @param clientAppId * @param requestId * @return */ public static CompletableFuture<ByteBuf> lookupTopicAsync(PulsarService pulsarService, TopicName topicName, boolean authoritative, String clientAppId, AuthenticationDataSource authenticationData, long requestId) { final CompletableFuture<ByteBuf> validationFuture = new CompletableFuture<>(); final CompletableFuture<ByteBuf> lookupfuture = new CompletableFuture<>(); final String cluster = topicName.getCluster(); // (1) validate cluster getClusterDataIfDifferentCluster(pulsarService, cluster, clientAppId).thenAccept(differentClusterData -> { if (differentClusterData != null) { if (log.isDebugEnabled()) { log.debug("[{}] Redirecting the lookup call to {}/{} cluster={}", clientAppId, differentClusterData.getBrokerServiceUrl(), differentClusterData.getBrokerServiceUrlTls(), cluster); } validationFuture.complete(newLookupResponse(differentClusterData.getBrokerServiceUrl(), differentClusterData.getBrokerServiceUrlTls(), true, LookupType.Redirect, requestId, false)); } else { // (2) authorize client try { checkAuthorization(pulsarService, topicName, clientAppId, authenticationData); } catch (RestException authException) { log.warn("Failed to authorized {} on cluster {}", clientAppId, topicName.toString()); validationFuture.complete(newLookupErrorResponse(ServerError.AuthorizationError, authException.getMessage(), requestId)); return; } catch (Exception e) { log.warn("Unknown error while authorizing {} on cluster {}", clientAppId, topicName.toString()); validationFuture.completeExceptionally(e); return; } // (3) validate global namespace checkLocalOrGetPeerReplicationCluster(pulsarService, topicName.getNamespaceObject()) .thenAccept(peerClusterData -> { if (peerClusterData == null) { // (4) all validation passed: initiate lookup validationFuture.complete(null); return; } // if peer-cluster-data is present it means namespace is owned by that peer-cluster and // request should be redirect to the peer-cluster if (StringUtils.isBlank(peerClusterData.getBrokerServiceUrl()) && StringUtils.isBlank(peerClusterData.getBrokerServiceUrl())) { validationFuture.complete(newLookupErrorResponse(ServerError.MetadataError, "Redirected cluster's brokerService url is not configured", requestId)); return; } validationFuture.complete(newLookupResponse(peerClusterData.getBrokerServiceUrl(), peerClusterData.getBrokerServiceUrlTls(), true, LookupType.Redirect, requestId, false)); }).exceptionally(ex -> { validationFuture.complete( newLookupErrorResponse(ServerError.MetadataError, ex.getMessage(), requestId)); return null; }); } }).exceptionally(ex -> { validationFuture.completeExceptionally(ex); return null; }); // Initiate lookup once validation completes validationFuture.thenAccept(validaitonFailureResponse -> { if (validaitonFailureResponse != null) { lookupfuture.complete(validaitonFailureResponse); } else { pulsarService.getNamespaceService().getBrokerServiceUrlAsync(topicName, authoritative) .thenAccept(lookupResult -> { if (log.isDebugEnabled()) { log.debug("[{}] Lookup result {}", topicName.toString(), lookupResult); } if (!lookupResult.isPresent()) { lookupfuture.complete(newLookupErrorResponse(ServerError.ServiceNotReady, "No broker was available to own " + topicName, requestId)); return; } LookupData lookupData = lookupResult.get().getLookupData(); if (lookupResult.get().isRedirect()) { boolean newAuthoritative = isLeaderBroker(pulsarService); lookupfuture.complete( newLookupResponse(lookupData.getBrokerUrl(), lookupData.getBrokerUrlTls(), newAuthoritative, LookupType.Redirect, requestId, false)); } else { // When running in standalone mode we want to redirect the client through the service // url, so that the advertised address configuration is not relevant anymore. boolean redirectThroughServiceUrl = pulsarService.getConfiguration() .isRunningStandalone(); lookupfuture.complete(newLookupResponse(lookupData.getBrokerUrl(), lookupData.getBrokerUrlTls(), true /* authoritative */, LookupType.Connect, requestId, redirectThroughServiceUrl)); } }).exceptionally(ex -> { if (ex instanceof CompletionException && ex.getCause() instanceof IllegalStateException) { log.info("Failed to lookup {} for topic {} with error {}", clientAppId, topicName.toString(), ex.getCause().getMessage()); } else { log.warn("Failed to lookup {} for topic {} with error {}", clientAppId, topicName.toString(), ex.getMessage(), ex); } lookupfuture.complete(newLookupErrorResponse(ServerError.ServiceNotReady, ex.getMessage(), requestId)); return null; }); } }).exceptionally(ex -> { if (ex instanceof CompletionException && ex.getCause() instanceof IllegalStateException) { log.info("Failed to lookup {} for topic {} with error {}", clientAppId, topicName.toString(), ex.getCause().getMessage()); } else { log.warn("Failed to lookup {} for topic {} with error {}", clientAppId, topicName.toString(), ex.getMessage(), ex); } lookupfuture.complete(newLookupErrorResponse(ServerError.ServiceNotReady, ex.getMessage(), requestId)); return null; }); return lookupfuture; } private void completeLookupResponseExceptionally(AsyncResponse asyncResponse, Throwable t) { pulsar().getBrokerService().getLookupRequestSemaphore().release(); asyncResponse.resume(t); } private void completeLookupResponseSuccessfully(AsyncResponse asyncResponse, LookupData lookupData) { pulsar().getBrokerService().getLookupRequestSemaphore().release(); asyncResponse.resume(lookupData); } protected TopicName getTopicName(String topicDomain, String tenant, String cluster, String namespace, @Encoded String encodedTopic) { String decodedName = Codec.decode(encodedTopic); return TopicName.get(TopicDomain.getEnum(topicDomain).value(), tenant, cluster, namespace, decodedName); } protected TopicName getTopicName(String topicDomain, String tenant, String namespace, @Encoded String encodedTopic) { String decodedName = Codec.decode(encodedTopic); return TopicName.get(TopicDomain.getEnum(topicDomain).value(), tenant, namespace, decodedName); } private static final Logger log = LoggerFactory.getLogger(TopicLookupBase.class); }