Github user uce commented on a diff in the pull request:
https://github.com/apache/flink/pull/3460#discussion_r105874859
--- Diff:
flink-runtime-web/src/main/java/org/apache/flink/runtime/webmonitor/history/HistoryServer.java
---
@@ -0,0 +1,276 @@
+/*
+ * 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 io.netty.handler.codec.http.router.Router;
+import org.apache.flink.api.java.utils.ParameterTool;
+import org.apache.flink.configuration.Configuration;
+import org.apache.flink.configuration.GlobalConfiguration;
+import org.apache.flink.configuration.HistoryServerOptions;
+import org.apache.flink.core.fs.FileSystem;
+import org.apache.flink.core.fs.Path;
+import org.apache.flink.runtime.net.SSLUtils;
+import org.apache.flink.runtime.security.SecurityUtils;
+import org.apache.flink.runtime.webmonitor.handlers.DashboardConfigHandler;
+import org.apache.flink.runtime.webmonitor.utils.WebFrontendBootstrap;
+import org.apache.flink.util.FileUtils;
+import org.apache.flink.util.FlinkException;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import javax.net.ssl.SSLContext;
+import java.io.File;
+import java.io.FileWriter;
+import java.io.IOException;
+import java.lang.reflect.UndeclaredThrowableException;
+import java.nio.file.Files;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.UUID;
+import java.util.concurrent.Callable;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.atomic.AtomicBoolean;
+
+public class HistoryServer {
+
+ private static final Logger LOG =
LoggerFactory.getLogger(HistoryServer.class);
+
+ private final String webAddress;
+ private final int webPort;
+ private final long webRefreshIntervalMillis;
+ private final File webDir;
+
+ private final HistoryServerArchiveFetcher archiveFetcher;
+
+ private final SSLContext serverSSLContext;
+ private WebFrontendBootstrap netty;
+
+ private final Object startupShutdownLock = new Object();
+ private final AtomicBoolean shutdownRequested = new
AtomicBoolean(false);
+ private final Thread shutdownHook;
+
+ public static void main(String[] args) throws Exception {
+ ParameterTool pt = ParameterTool.fromArgs(args);
+ String configDir = pt.getRequired("configDir");
+
+ LOG.info("Loading configuration from {}", configDir);
+ final Configuration flinkConfig =
GlobalConfiguration.loadConfiguration(configDir);
+
+ // run the job manager
+ SecurityUtils.install(new
SecurityUtils.SecurityConfiguration(flinkConfig));
+
+ try {
+ SecurityUtils.getInstalledContext().runSecured(new
Callable<Integer>() {
+ @Override
+ public Integer call() throws Exception {
+ HistoryServer hs = new
HistoryServer(flinkConfig);
+ hs.run();
+ return 0;
+ }
+ });
+ System.exit(0);
+ } catch (UndeclaredThrowableException ute) {
+ Throwable cause = ute. getUndeclaredThrowable();
+ LOG.error("Failed to run HistoryServer.", cause);
+ cause.printStackTrace();
+ System.exit(1);
+ } catch (Exception e) {
+ LOG.error("Failed to run HistoryServer.", e);
+ e.printStackTrace();
+ System.exit(1);
+ }
+ }
+
+ public HistoryServer(Configuration config) throws IOException,
FlinkException {
+ if
(config.getBoolean(HistoryServerOptions.HISTORY_SERVER_WEB_SSL_ENABLED) &&
SSLUtils.getSSLEnabled(config)) {
+ LOG.info("Enabling ssl for the history server.");
+ try {
+ this.serverSSLContext =
SSLUtils.createSSLServerContext(config);
+ } catch (Exception e) {
+ throw new IOException("Failed to initialize
SSLContext for the history server.", e);
+ }
+ } else {
+ this.serverSSLContext = null;
+ }
+
+ webAddress =
config.getString(HistoryServerOptions.HISTORY_SERVER_WEB_ADDRESS);
+ webPort =
config.getInteger(HistoryServerOptions.HISTORY_SERVER_WEB_PORT);
+ webRefreshIntervalMillis =
config.getLong(HistoryServerOptions.HISTORY_SERVER_WEB_REFRESH_INTERVAL);
+
+ String webDirectory =
config.getString(HistoryServerOptions.HISTORY_SERVER_WEB_DIR);
+ if (webDirectory == null) {
+ webDirectory = System.getProperty("java.io.tmpdir") +
"flink-web-history-" + UUID.randomUUID();
+ }
+ webDir = new File(webDirectory);
+
+ String refreshDirectories =
config.getString(HistoryServerOptions.HISTORY_SERVER_DIRS);
+ if (refreshDirectories == null) {
+ throw new
FlinkException(HistoryServerOptions.HISTORY_SERVER_DIRS + " was not
configured.");
+ }
+ List<RefreshLocation> refreshDirs = new ArrayList<>();
+ for (String refreshDirectory : refreshDirectories.split(",")) {
+ try {
+ Path refreshPath = new Path(refreshDirectory);
+ FileSystem refreshFS =
refreshPath.getFileSystem();
+ refreshDirs.add(new
RefreshLocation(refreshPath, refreshFS));
+ } catch (Exception e) {
+ // there's most likely something wrong with the
path itself, so we ignore it from here on
+ LOG.error("Failed to create Path or FileSystem
for directory {}.", refreshDirectory, e);
+ }
+ }
+
+ long refreshIntervalMillis =
config.getLong(HistoryServerOptions.HISTORY_SERVER_REFRESH_INTERVAL);
+ archiveFetcher = new
HistoryServerArchiveFetcher(refreshIntervalMillis, refreshDirs, webDir);
+
+ this.shutdownHook = new Thread() {
+ @Override
+ public void run() {
+ HistoryServer.this.stop();
+ }
+ };
+ // add shutdown hook for deleting the directories and remaining
temp files on shutdown
+ try {
+ Runtime.getRuntime().addShutdownHook(shutdownHook);
+ } catch (IllegalStateException e) {
+ // race, JVM is in shutdown already, we can safely
ignore this
+ LOG.debug("Unable to add shutdown hook, shutdown
already in progress", e);
+ } catch (Throwable t) {
+ // these errors usually happen when the shutdown is
already in progress
+ LOG.warn("Error while adding shutdown hook", t);
+ }
+ }
+
+ public void run() {
+ try {
+ start();
+ while (true) {
--- End diff --
We don't need the while loop and catch block here. There are no spurious
wakeups with the `CountDownLatch` and reacting to an interrupt in the main
Thread is good I think.
The `while-catch-interrupt` pattern here leads to an endless loop.
```java
Thread t = new Thread() {
@Override
public void run() {
CountDownLatch latch = new CountDownLatch(1);
while (true) {
try {
latch.await();
} catch (InterruptedException e) {
e.printStackTrace();
Thread.currentThread().interrupt();
}
}
}
};
t.start();
while (!t.isAlive()) {
}
t.interrupt();
t.join(); // Thread never terminates interruption loop
```
The one thing to remember is that interruptions are cooperative and you
have to manually check and respect the interrupted flag.
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