michael-o commented on a change in pull request #179: HTTPCLIENT-2034: Introduce HttpRequestRetryStrategy URL: https://github.com/apache/httpcomponents-client/pull/179#discussion_r355639522
########## File path: httpclient5/src/main/java/org/apache/hc/client5/http/impl/async/AsyncHttpRequestRetryExec.java ########## @@ -0,0 +1,187 @@ +/* + * ==================================================================== + * 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. + * ==================================================================== + * + * This software consists of voluntary contributions made by many + * individuals on behalf of the Apache Software Foundation. For more + * information on the Apache Software Foundation, please see + * <http://www.apache.org/>. + * + */ +package org.apache.hc.client5.http.impl.async; + +import java.io.IOException; + +import org.apache.hc.client5.http.HttpRequestRetryStrategy; +import org.apache.hc.client5.http.HttpRoute; +import org.apache.hc.client5.http.async.AsyncExecCallback; +import org.apache.hc.client5.http.async.AsyncExecChain; +import org.apache.hc.client5.http.async.AsyncExecChainHandler; +import org.apache.hc.client5.http.impl.RequestCopier; +import org.apache.hc.client5.http.protocol.HttpClientContext; +import org.apache.hc.core5.annotation.Contract; +import org.apache.hc.core5.annotation.Internal; +import org.apache.hc.core5.annotation.ThreadingBehavior; +import org.apache.hc.core5.http.EntityDetails; +import org.apache.hc.core5.http.HttpException; +import org.apache.hc.core5.http.HttpRequest; +import org.apache.hc.core5.http.HttpResponse; +import org.apache.hc.core5.http.nio.AsyncDataConsumer; +import org.apache.hc.core5.http.nio.AsyncEntityProducer; +import org.apache.hc.core5.http.nio.entity.NoopEntityConsumer; +import org.apache.hc.core5.util.Args; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +/** + * Request executor in the asynchronous request execution chain that is + * responsible for making a decision whether a request that failed due to + * an I/O exception or received a specific response from the target server should + * be re-executed. Note that this exec chain handler <em>will not</em> respect + * {@link HttpRequestRetryStrategy#getRetryInterval(HttpResponse, int, org.apache.hc.core5.http.protocol.HttpContext)}. + * <p> + * Further responsibilities such as communication with the opposite + * endpoint is delegated to the next executor in the request execution + * chain. + * </p> + * + * @since 5.0 + */ +@Contract(threading = ThreadingBehavior.STATELESS) +@Internal +public final class AsyncHttpRequestRetryExec implements AsyncExecChainHandler { + + private final Logger log = LoggerFactory.getLogger(getClass()); + + private final HttpRequestRetryStrategy retryStrategy; + + public AsyncHttpRequestRetryExec(final HttpRequestRetryStrategy retryStrategy) { + Args.notNull(retryStrategy, "retryStrategy"); + this.retryStrategy = retryStrategy; + } + + private static class State { + + volatile int execCount; + volatile boolean retrying; + + } + + private void internalExecute( + final State state, + final HttpRequest request, + final AsyncEntityProducer entityProducer, + final AsyncExecChain.Scope scope, + final AsyncExecChain chain, + final AsyncExecCallback asyncExecCallback) throws HttpException, IOException { + + final String exchangeId = scope.exchangeId; + + chain.proceed(RequestCopier.INSTANCE.copy(request), entityProducer, scope, new AsyncExecCallback() { + + @Override + public AsyncDataConsumer handleResponse( + final HttpResponse response, + final EntityDetails entityDetails) throws HttpException, IOException { + final HttpClientContext clientContext = scope.clientContext; + if (entityProducer != null && !entityProducer.isRepeatable()) { + if (log.isDebugEnabled()) { + log.debug("{}: cannot retry non-repeatable request", exchangeId); + } + return asyncExecCallback.handleResponse(response, entityDetails); + } + state.retrying = retryStrategy.retryRequest(response, state.execCount, clientContext); + if (state.retrying) { + return new NoopEntityConsumer(); + } else { + return asyncExecCallback.handleResponse(response, entityDetails); + } + } + + @Override + public void handleInformationResponse(final HttpResponse response) throws HttpException, IOException { + asyncExecCallback.handleInformationResponse(response); + } + + @Override + public void completed() { + if (state.retrying) { + state.execCount++; + try { + internalExecute(state, request, entityProducer, scope, chain, asyncExecCallback); + } catch (final IOException | HttpException ex) { + asyncExecCallback.failed(ex); + } + } else { + asyncExecCallback.completed(); + } + } + + @Override + public void failed(final Exception cause) { + if (cause instanceof IOException) { + final HttpRoute route = scope.route; + final HttpClientContext clientContext = scope.clientContext; + if (entityProducer != null && !entityProducer.isRepeatable()) { + if (log.isDebugEnabled()) { + log.debug("{}: cannot retry non-repeatable request", exchangeId); + } + } else if (retryStrategy.retryRequest(request, (IOException) cause, state.execCount, clientContext)) { + if (log.isDebugEnabled()) { + log.debug("{}: {}", exchangeId, cause.getMessage(), cause); + } + if (log.isInfoEnabled()) { + log.info("Recoverable I/O exception ({}) caught when processing request to {}", + cause.getClass().getName(), route); + } + scope.execRuntime.discardEndpoint(); + if (entityProducer != null) { + entityProducer.releaseResources(); + } + state.retrying = true; + state.execCount++; + try { + internalExecute(state, request, entityProducer, scope, chain, asyncExecCallback); + } catch (final IOException | HttpException ex) { + asyncExecCallback.failed(ex); + } + return; + } + } + asyncExecCallback.failed(cause); + } + + }); + + } + + @Override + public void execute( + final HttpRequest request, + final AsyncEntityProducer entityProducer, + final AsyncExecChain.Scope scope, + final AsyncExecChain chain, + final AsyncExecCallback asyncExecCallback) throws HttpException, IOException { + final State state = new State(); + state.execCount = 1; Review comment: That's a private class, consider it like a record or value class. I see no benefit. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected] With regards, Apache Git Services --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
