| /* |
| * 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.solr.client.solrj.impl; |
| |
| import java.io.IOException; |
| import java.net.ConnectException; |
| import java.net.SocketException; |
| import java.net.SocketTimeoutException; |
| import java.util.Arrays; |
| import java.util.concurrent.atomic.AtomicBoolean; |
| import java.util.concurrent.atomic.AtomicReference; |
| |
| import org.apache.solr.client.solrj.SolrClient; |
| import org.apache.solr.client.solrj.SolrServerException; |
| import org.apache.solr.client.solrj.request.IsUpdateRequest; |
| import org.apache.solr.client.solrj.util.Cancellable; |
| import org.apache.solr.client.solrj.util.AsyncListener; |
| import org.apache.solr.common.SolrException; |
| import org.apache.solr.common.util.NamedList; |
| import org.slf4j.MDC; |
| |
| import static org.apache.solr.common.params.CommonParams.ADMIN_PATHS; |
| |
| /** |
| * LBHttp2SolrClient or "LoadBalanced LBHttp2SolrClient" is a load balancing wrapper around |
| * {@link Http2SolrClient}. This is useful when you |
| * have multiple Solr servers and the requests need to be Load Balanced among them. |
| * |
| * Do <b>NOT</b> use this class for indexing in leader/follower scenarios since documents must be sent to the |
| * correct leader; no inter-node routing is done. |
| * |
| * In SolrCloud (leader/replica) scenarios, it is usually better to use |
| * {@link CloudSolrClient}, but this class may be used |
| * for updates because the server will forward them to the appropriate leader. |
| * |
| * <p> |
| * It offers automatic failover when a server goes down and it detects when the server comes back up. |
| * <p> |
| * Load balancing is done using a simple round-robin on the list of servers. |
| * <p> |
| * If a request to a server fails by an IOException due to a connection timeout or read timeout then the host is taken |
| * off the list of live servers and moved to a 'dead server list' and the request is resent to the next live server. |
| * This process is continued till it tries all the live servers. If at least one server is alive, the request succeeds, |
| * and if not it fails. |
| * <blockquote><pre> |
| * SolrClient lbHttp2SolrClient = new LBHttp2SolrClient(http2SolrClient, "http://host1:8080/solr/", "http://host2:8080/solr", "http://host2:8080/solr"); |
| * </pre></blockquote> |
| * This detects if a dead server comes alive automatically. The check is done in fixed intervals in a dedicated thread. |
| * This interval can be set using {@link #setAliveCheckInterval} , the default is set to one minute. |
| * <p> |
| * <b>When to use this?</b><br> This can be used as a software load balancer when you do not wish to setup an external |
| * load balancer. Alternatives to this code are to use |
| * a dedicated hardware load balancer or using Apache httpd with mod_proxy_balancer as a load balancer. See <a |
| * href="http://en.wikipedia.org/wiki/Load_balancing_(computing)">Load balancing on Wikipedia</a> |
| * |
| * @lucene.experimental |
| * @since solr 8.0 |
| */ |
| public class LBHttp2SolrClient extends LBSolrClient { |
| private Http2SolrClient httpClient; |
| |
| public LBHttp2SolrClient(Http2SolrClient httpClient, String... baseSolrUrls) { |
| super(Arrays.asList(baseSolrUrls)); |
| this.httpClient = httpClient; |
| } |
| @Override |
| protected SolrClient getClient(String baseUrl) { |
| return httpClient; |
| } |
| |
| public Cancellable asyncReq(Req req, AsyncListener<Rsp> asyncListener) { |
| Rsp rsp = new Rsp(); |
| boolean isNonRetryable = req.request instanceof IsUpdateRequest || ADMIN_PATHS.contains(req.request.getPath()); |
| ServerIterator it = new ServerIterator(req, zombieServers); |
| asyncListener.onStart(); |
| final AtomicBoolean cancelled = new AtomicBoolean(false); |
| AtomicReference<Cancellable> currentCancellable = new AtomicReference<>(); |
| RetryListener retryListener = new RetryListener() { |
| |
| @Override |
| public void onSuccess(Rsp rsp) { |
| asyncListener.onSuccess(rsp); |
| } |
| |
| @Override |
| public void onFailure(Exception e, boolean retryReq) { |
| if (retryReq) { |
| String url; |
| try { |
| url = it.nextOrError(e); |
| } catch (SolrServerException ex) { |
| asyncListener.onFailure(e); |
| return; |
| } |
| try { |
| MDC.put("LBSolrClient.url", url); |
| synchronized (cancelled) { |
| if (cancelled.get()) { |
| return; |
| } |
| Cancellable cancellable = doRequest(url, req, rsp, isNonRetryable, it.isServingZombieServer(), this); |
| currentCancellable.set(cancellable); |
| } |
| } finally { |
| MDC.remove("LBSolrClient.url"); |
| } |
| } else { |
| asyncListener.onFailure(e); |
| } |
| } |
| }; |
| try { |
| Cancellable cancellable = doRequest(it.nextOrError(), req, rsp, isNonRetryable, it.isServingZombieServer(), retryListener); |
| currentCancellable.set(cancellable); |
| } catch (SolrServerException e) { |
| asyncListener.onFailure(e); |
| } |
| return () -> { |
| synchronized (cancelled) { |
| cancelled.set(true); |
| if (currentCancellable.get() != null) { |
| currentCancellable.get().cancel(); |
| } |
| } |
| }; |
| } |
| |
| private interface RetryListener { |
| void onSuccess(Rsp rsp); |
| void onFailure(Exception e, boolean retryReq); |
| } |
| |
| private Cancellable doRequest(String baseUrl, Req req, Rsp rsp, boolean isNonRetryable, |
| boolean isZombie, RetryListener listener) { |
| rsp.server = baseUrl; |
| req.getRequest().setBasePath(baseUrl); |
| return ((Http2SolrClient)getClient(baseUrl)).asyncRequest(req.getRequest(), null, new AsyncListener<>() { |
| @Override |
| public void onSuccess(NamedList<Object> result) { |
| rsp.rsp = result; |
| if (isZombie) { |
| zombieServers.remove(baseUrl); |
| } |
| listener.onSuccess(rsp); |
| } |
| |
| @Override |
| public void onFailure(Throwable oe) { |
| try { |
| throw (Exception) oe; |
| } catch (BaseHttpSolrClient.RemoteExecutionException e) { |
| listener.onFailure(e, false); |
| } catch (SolrException e) { |
| // we retry on 404 or 403 or 503 or 500 |
| // unless it's an update - then we only retry on connect exception |
| if (!isNonRetryable && RETRY_CODES.contains(e.code())) { |
| listener.onFailure((!isZombie) ? addZombie(baseUrl, e) : e, true); |
| } else { |
| // Server is alive but the request was likely malformed or invalid |
| if (isZombie) { |
| zombieServers.remove(baseUrl); |
| } |
| listener.onFailure(e, false); |
| } |
| } catch (SocketException e) { |
| if (!isNonRetryable || e instanceof ConnectException) { |
| listener.onFailure((!isZombie) ? addZombie(baseUrl, e) : e, true); |
| } else { |
| listener.onFailure(e, false); |
| } |
| } catch (SocketTimeoutException e) { |
| if (!isNonRetryable) { |
| listener.onFailure((!isZombie) ? addZombie(baseUrl, e) : e, true); |
| } else { |
| listener.onFailure(e, false); |
| } |
| } catch (SolrServerException e) { |
| Throwable rootCause = e.getRootCause(); |
| if (!isNonRetryable && rootCause instanceof IOException) { |
| listener.onFailure((!isZombie) ? addZombie(baseUrl, e) : e, true); |
| } else if (isNonRetryable && rootCause instanceof ConnectException) { |
| listener.onFailure((!isZombie) ? addZombie(baseUrl, e) : e, true); |
| } else { |
| listener.onFailure(e, false); |
| } |
| } catch (Exception e) { |
| listener.onFailure(new SolrServerException(e), false); |
| } |
| } |
| }); |
| } |
| } |
