nfsantos commented on code in PR #728: URL: https://github.com/apache/jackrabbit-oak/pull/728#discussion_r990163894
########## oak-run/src/main/java/org/apache/jackrabbit/oak/run/Downloader.java: ########## @@ -0,0 +1,148 @@ +/* + * 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.jackrabbit.oak.run; + +import com.google.common.util.concurrent.ThreadFactoryBuilder; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import java.io.Closeable; +import java.io.FileOutputStream; +import java.io.IOException; +import java.net.URL; +import java.net.URLConnection; +import java.nio.channels.Channels; +import java.nio.channels.ReadableByteChannel; +import java.nio.file.Files; +import java.nio.file.Path; +import java.nio.file.Paths; +import java.util.ArrayList; +import java.util.List; +import java.util.concurrent.Callable; +import java.util.concurrent.ExecutionException; +import java.util.concurrent.ExecutorService; +import java.util.concurrent.Future; +import java.util.concurrent.LinkedBlockingQueue; +import java.util.concurrent.ThreadPoolExecutor; +import java.util.concurrent.TimeUnit; +import java.util.stream.Collectors; + +/** + * Generic concurrent file downloader which uses Java NIO channels to potentially leverage OS internal optimizations. + */ +public class Downloader implements Closeable { + + private static final Logger LOG = LoggerFactory.getLogger(Downloader.class); + + private final ExecutorService executorService; + private final int connectTimeoutMs; + private final int readTimeoutMs; + private final List<Future<ItemResponse>> responses; + + public Downloader(int concurrency, int connectTimeoutMs, int readTimeoutMs) { + if (concurrency <= 0 || concurrency > 1000) { + throw new IllegalArgumentException("concurrency range must be between 1 and 1000"); + } + if (connectTimeoutMs < 0 || readTimeoutMs < 0) { + throw new IllegalArgumentException("connect and/or read timeouts can not be negative"); + } + LOG.info("Initializing Downloader with max number of concurrent requests={}", concurrency); + this.connectTimeoutMs = connectTimeoutMs; + this.readTimeoutMs = readTimeoutMs; + this.executorService = new ThreadPoolExecutor( + (int) Math.ceil(concurrency * .1), concurrency, 60L, TimeUnit.SECONDS, + new LinkedBlockingQueue<>(), + new ThreadFactoryBuilder() + .setNameFormat("downloader-%d") + .setDaemon(true) + .build() + ); + this.responses = new ArrayList<>(); + } + + public void offer(Item item) { + Callable<ItemResponse> callableTask = () -> { + ItemResponse response = new ItemResponse(item); + long t0 = System.nanoTime(); + try { + URLConnection sourceUrl = new URL(item.source).openConnection(); + sourceUrl.setConnectTimeout(Downloader.this.connectTimeoutMs); + sourceUrl.setReadTimeout(Downloader.this.readTimeoutMs); + + Path destinationPath = Paths.get(item.destination); + Files.createDirectories(destinationPath.getParent()); + try (ReadableByteChannel byteChannel = Channels.newChannel(sourceUrl.getInputStream()); + FileOutputStream outputStream = new FileOutputStream(destinationPath.toFile())) { + response.size = outputStream.getChannel() + .transferFrom(byteChannel, 0, sourceUrl.getContentLengthLong()); + } + } catch (Exception e) { + LOG.error("Error downloading " + item.source + ": " + e.getMessage()); + response.failed = true; + response.throwable = e; + } finally { + response.time = TimeUnit.NANOSECONDS.toMillis(System.nanoTime() - t0); + } + return response; + }; + responses.add(this.executorService.submit(callableTask)); + } + + public List<ItemResponse> waitUntilComplete() { + return responses.stream() + .map(itemResponseFuture -> { + try { + return itemResponseFuture.get(); + } catch (InterruptedException | ExecutionException e) { + throw new RuntimeException(e); + } Review Comment: It would be nice to have a test that exercises this code path, a download that fails with a RuntimeException, to complement the test where one file fails to download with an IOException. More concretely, what happens if during a transfer one of the downloads fails with a RuntimeException? `waitUntilComplete` will abort without calling .get in the remaining tasks. The main program will call shutdown in its finally block, which tries to do an orderly shutdown, waiting for the tasks to complete. But I guess this is not a problem, because shutdown() does not block waiting for the tasks to finish, and the main method will exit after calling shutdown. -- 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. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
