Github user uce commented on a diff in the pull request:
https://github.com/apache/flink/pull/3460#discussion_r105899831
--- Diff:
flink-runtime-web/src/main/java/org/apache/flink/runtime/webmonitor/history/HistoryServerArchiveFetcher.java
---
@@ -0,0 +1,244 @@
+/*
+ * 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.flink.runtime.webmonitor.history;
+
+import com.fasterxml.jackson.core.JsonFactory;
+import com.fasterxml.jackson.core.JsonGenerator;
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import org.apache.flink.configuration.HistoryServerOptions;
+import org.apache.flink.core.fs.FileStatus;
+import org.apache.flink.core.fs.FileSystem;
+import org.apache.flink.core.fs.Path;
+import org.apache.flink.runtime.filecache.FileCache;
+import org.apache.flink.runtime.util.ExecutorThreadFactory;
+import
org.apache.flink.runtime.webmonitor.handlers.CurrentJobsOverviewHandler;
+import org.apache.flink.util.FileUtils;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.File;
+import java.io.FileWriter;
+import java.io.IOException;
+import java.nio.file.FileAlreadyExistsException;
+import java.nio.file.Files;
+import java.nio.file.NoSuchFileException;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.TimerTask;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.TimeUnit;
+
+public class HistoryServerArchiveFetcher {
+
+ private static final Logger LOG =
LoggerFactory.getLogger(HistoryServerArchiveFetcher.class);
+
+ private static final JsonFactory jacksonFactory = new JsonFactory();
+ private static final ObjectMapper mapper = new ObjectMapper();
+
+ private final ScheduledExecutorService executor =
Executors.newSingleThreadScheduledExecutor(
+ new
ExecutorThreadFactory("Flink-HistoryServer-ArchiveFetcher"));
+ private final JobArchiveFetcherTask fetcherTask;
+ private final long refreshIntervalMillis;
+
+ HistoryServerArchiveFetcher(long refreshIntervalMillis,
List<HistoryServer.RefreshLocation> refreshDirs, File webDir) {
+ this.refreshIntervalMillis = refreshIntervalMillis;
+ this.fetcherTask = new JobArchiveFetcherTask(refreshDirs,
webDir);
+ if (LOG.isInfoEnabled()) {
+ for (HistoryServer.RefreshLocation refreshDir :
refreshDirs) {
+ LOG.info("Monitoring directory {} for archived
jobs.", refreshDir.getPath());
+ }
+ }
+ }
+
+ void start() {
+ executor.scheduleWithFixedDelay(fetcherTask, 0,
refreshIntervalMillis, TimeUnit.MILLISECONDS);
+ }
+
+ void stop() {
+ executor.shutdown();
+
+ try {
+ if (!executor.awaitTermination(1, TimeUnit.SECONDS)) {
+ executor.shutdownNow();
+ }
+ } catch (InterruptedException ignored) {
+ executor.shutdownNow();
+ }
+ }
+
+ /**
+ * {@link TimerTask} that polls the directories configured as {@link
HistoryServerOptions#HISTORY_SERVER_DIRS} for
+ * new job archives.
+ */
+ static class JobArchiveFetcherTask extends TimerTask {
+ private final List<HistoryServer.RefreshLocation> refreshDirs;
+ /** Map containing the JobID of all fetched jobs and the
refreshDir from with they originate. */
+ private final Map<String, Path> cachedArchives;
+ private final File webDir;
+ private final File webTmpDir;
+ private final File webJobDir;
+ private final File webOverviewDir;
+
+ private static final String JSON_FILE_ENDING = ".json";
+
+ JobArchiveFetcherTask(List<HistoryServer.RefreshLocation>
refreshDirs, File webDir) {
+ this.refreshDirs = refreshDirs;
+ this.cachedArchives = new HashMap<>();
+ this.webDir = webDir;
+ this.webTmpDir = new File(webDir, "tmp");
+ webTmpDir.mkdir();
+ this.webJobDir = new File(webDir, "jobs");
+ webJobDir.mkdir();
+ this.webOverviewDir = new File(webDir, "overviews");
+ webOverviewDir.mkdir();
+ }
+
+ @Override
+ public void run() {
+ try {
+ for (HistoryServer.RefreshLocation
refreshLocation : refreshDirs) {
+ Path refreshDir =
refreshLocation.getPath();
+ FileSystem refreshFS =
refreshLocation.getFs();
+
+ // contents of /:refreshDir
+ FileStatus[] jobArchives;
+ try {
+ jobArchives =
refreshFS.listStatus(refreshDir);
+ } catch (IOException e) {
+ LOG.error("Failed to access job
archive location for path {}.", refreshDir, e);
+ continue;
+ }
+ if (jobArchives == null) {
+ continue;
+ }
+ boolean updateOverview = false;
+ for (FileStatus jobArchive :
jobArchives) {
+ Path jobArchivePath =
jobArchive.getPath();
+ String jobID =
jobArchivePath.getName();
+ if (cachedArchives.put(jobID,
refreshDir) == null) {
+ File tmpLocalFile = new
File(webTmpDir, jobID);
+ Path tmpLocalPath = new
Path(webTmpDir.getAbsolutePath(), jobID);
+ try {
+
FileCache.copy(jobArchive.getPath(), tmpLocalPath, false);
+
+ JsonNode
archive = mapper.readTree(tmpLocalFile);
+ for (JsonNode
archivePart : archive.get(ArchivedJson.ARCHIVE)) {
+ String
path = archivePart.get(ArchivedJson.PATH).asText();
+ String
json = archivePart.get(ArchivedJson.JSON).asText();
+
+ File
target;
+ if
(path.equals("/joboverview")) {
+
target = new File(webOverviewDir, jobID + JSON_FILE_ENDING);
+ } else {
+
target = new File(webDir, path + JSON_FILE_ENDING);
+ }
+
+
java.nio.file.Path parent = target.getParentFile().toPath();
+
+ try {
+
Files.createDirectories(parent);
+ } catch
(FileAlreadyExistsException ignored) {
+
// odd, but OK
+ }
+
+
java.nio.file.Path targetPath = target.toPath();
+ /**
+ * We
overwrite existing files since this may be another attempt at fetching this
archive.
+ *
Existing files may be incomplete/corrupt.
+ */
+ if
(Files.exists(targetPath)) {
+
Files.delete(targetPath);
+ }
+
+
Files.createFile(target.toPath());
+ try
(FileWriter fw = new FileWriter(target)) {
+
fw.write(json);
+
fw.flush();
+ }
+ }
+ updateOverview
= true;
+ } catch (IOException e)
{
+
LOG.error("Failure while fetching/processing job archive.", e);
+ /** Make sure
we attempt to fetch the archive again */
+
cachedArchives.remove(jobID);
+ /** Make sure
we do not include this job in the overview */
+
Files.delete(new File(webOverviewDir, jobID + JSON_FILE_ENDING).toPath());
+ /** Clean up
job files we may have created */
+ File
jobDirectory = new File(webJobDir, jobID);
+ try {
+
FileUtils.deleteDirectory(jobDirectory);
+ } catch
(IOException ioe) {
+
LOG.debug("Could not clean up job-directory.", ioe);
+ }
+ } finally {
+ try {
+
Files.delete(tmpLocalFile.toPath());
+ }
+ catch
(NoSuchFileException e) {
+ // if
the file is already gone (concurrently), we don't mind
+ }
+ }
+ }
+ }
+ if (updateOverview) {
+ updateJobOverview(webDir);
+ }
+ }
+ } catch (Exception e) {
+ LOG.error("Critical failure while
fetching/processing job archives.", e);
+ }
+ }
+ }
+
+ /**
+ * This method replicates the JSON response that would be given by the
{@link CurrentJobsOverviewHandler} when
+ * listing both running and finished jobs.
+ *
+ * Every job archive contains a joboverview.json file containing the
same structure. Since jobs are archived on
+ * their own however the list of finished jobs only contains a single
job.
+ *
+ * For the display in the HistoryServer WebFrontend we have to combine
these overviews.
+ */
+ private static void updateJobOverview(File webDir) {
--- End diff --
Why don't we simply count the number of jobs that we successfully add to
the cached map? Then we don't need to write a file for each update. We would
need to add a simple handler for this though.
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