Allow injecting shutdown hooks. Defer thread creation (Netflix#1581)

argha-c · Aug 1, 2023 · 88fb79e · 88fb79e
1 parent 8e2e4e1
commit 88fb79e
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Showing 3 changed files with 48 additions and 33 deletions.
diff --git a/zuul-core/src/main/java/com/netflix/zuul/FilterFileManager.java b/zuul-core/src/main/java/com/netflix/zuul/FilterFileManager.java
@@ -55,15 +55,12 @@ public class FilterFileManager {
 
     private final FilterFileManagerConfig config;
     private final FilterLoader filterLoader;
-    private final ExecutorService processFilesService;
+    private ExecutorService processFilesService;
 
     @Inject
     public FilterFileManager(FilterFileManagerConfig config, FilterLoader filterLoader) {
         this.config = config;
         this.filterLoader = filterLoader;
-        ThreadFactory tf =
-                new ThreadFactoryBuilder().setDaemon(true).setNameFormat("FilterFileManager_ProcessFiles-%d").build();
-        this.processFilesService = Executors.newFixedThreadPool(FILE_PROCESSOR_THREADS.get(), tf);
     }
 
     /**
@@ -72,10 +69,16 @@ public FilterFileManager(FilterFileManagerConfig config, FilterLoader filterLoad
      * @throws Exception
      */
     @Inject
-    public void init() throws Exception
-    {
+    public void init() throws Exception {
+        if(!config.enabled) {
+            return;
+        }
+
         long startTime = System.currentTimeMillis();
-
+        ThreadFactory tf =
+                new ThreadFactoryBuilder().setDaemon(true).setNameFormat("FilterFileManager_ProcessFiles-%d").build();
+        this.processFilesService = Executors.newFixedThreadPool(FILE_PROCESSOR_THREADS.get(), tf);
+
         filterLoader.putFiltersForClasses(config.getClassNames());
         manageFiles();
         startPoller();
@@ -200,12 +203,18 @@ public static class FilterFileManagerConfig
         private String[] classNames;
         private int pollingIntervalSeconds;
         private FilenameFilter filenameFilter;
+        boolean enabled;
 
         public FilterFileManagerConfig(String[] directories, String[] classNames, int pollingIntervalSeconds, FilenameFilter filenameFilter) {
+            this(directories, classNames, pollingIntervalSeconds, filenameFilter, true);
+        }
+
+        public FilterFileManagerConfig(String[] directories, String[] classNames, int pollingIntervalSeconds, FilenameFilter filenameFilter, boolean enabled) {
             this.directories = directories;
             this.classNames = classNames;
             this.pollingIntervalSeconds = pollingIntervalSeconds;
             this.filenameFilter = filenameFilter;
+            this.enabled = enabled;
         }
 
         public String[] getDirectories() {

diff --git a/zuul-core/src/main/java/com/netflix/zuul/netty/server/DirectMemoryMonitor.java b/zuul-core/src/main/java/com/netflix/zuul/netty/server/DirectMemoryMonitor.java
@@ -43,14 +43,13 @@ public final class DirectMemoryMonitor {
     private static final String PROP_PREFIX = "zuul.directmemory";
     private static final DynamicIntProperty TASK_DELAY_PROP = new DynamicIntProperty(PROP_PREFIX + ".task.delay", 10);
 
-    // TODO(carl-mastrangelo): this should be passed in as a dependency, so it can be shutdown and waited on for
-    //    termination.
-    private final ScheduledExecutorService service =
-            Executors.newSingleThreadScheduledExecutor(
-                    new ThreadFactoryBuilder().setDaemon(true).setNameFormat("dmm-%d").build());
+    private final ScheduledExecutorService service;
 
     @Inject
     public DirectMemoryMonitor(Registry registry) {
+        service = Executors.newSingleThreadScheduledExecutor(
+                new ThreadFactoryBuilder().setDaemon(true).setNameFormat("dmm-%d").build());
+
         PolledMeter.using(registry)
                    .withName(PROP_PREFIX + ".reserved")
                    .withDelay(Duration.ofSeconds(TASK_DELAY_PROP.get()))
@@ -65,6 +64,11 @@ public DirectMemoryMonitor(Registry registry) {
 
     }
 
+    public DirectMemoryMonitor() {
+        //no-op constructor
+        this.service = null;
+    }
+
     private static double getReservedMemory(Object discard) {
         try {
             return PlatformDependent.usedDirectMemory();

diff --git a/zuul-core/src/main/java/com/netflix/zuul/netty/server/Server.java b/zuul-core/src/main/java/com/netflix/zuul/netty/server/Server.java
@@ -120,7 +120,7 @@ public class Server
 
     private final EventLoopGroupMetrics eventLoopGroupMetrics;
 
-    private final Thread jvmShutdownHook = new Thread(this::stop, "Zuul-JVM-shutdown-hook");
+    private final Thread jvmShutdownHook;
     private final Registry registry;
     private ServerGroup serverGroup;
     private final ClientConnectionsShutdown clientConnectionsShutdown;
@@ -144,6 +144,7 @@ public class Server
      * EventLoopConfig)}
      * instead.
      */
+    @SuppressWarnings("rawtypes")
     @Deprecated
     public Server(Map<Integer, ChannelInitializer> portsToChannelInitializers, ServerStatusManager serverStatusManager,
                   ClientConnectionsShutdown clientConnectionsShutdown, EventLoopGroupMetrics eventLoopGroupMetrics)
@@ -157,7 +158,7 @@ public Server(Map<Integer, ChannelInitializer> portsToChannelInitializers, Serve
      * EventLoopConfig)}
      * instead.
      */
-    @SuppressWarnings("unchecked") // Channel init map has the wrong generics and we can't fix without api breakage.
+    @SuppressWarnings({"unchecked", "rawtypes"}) // Channel init map has the wrong generics and we can't fix without api breakage.
     @Deprecated
     public Server(Map<Integer, ChannelInitializer> portsToChannelInitializers, ServerStatusManager serverStatusManager,
                   ClientConnectionsShutdown clientConnectionsShutdown, EventLoopGroupMetrics eventLoopGroupMetrics,
@@ -177,24 +178,34 @@ public Server(Registry registry, ServerStatusManager serverStatusManager,
         this.clientConnectionsShutdown = checkNotNull(clientConnectionsShutdown, "clientConnectionsShutdown");
         this.eventLoopConfig = checkNotNull(eventLoopConfig, "eventLoopConfig");
         this.eventLoopGroupMetrics = checkNotNull(eventLoopGroupMetrics, "eventLoopGroupMetrics");
+        this.jvmShutdownHook = new Thread(this::stop, "Zuul-JVM-shutdown-hook");
     }
 
+    public Server(Registry registry, ServerStatusManager serverStatusManager,
+            Map<NamedSocketAddress, ? extends ChannelInitializer<?>> addressesToInitializers,
+            ClientConnectionsShutdown clientConnectionsShutdown, EventLoopGroupMetrics eventLoopGroupMetrics,
+            EventLoopConfig eventLoopConfig, Thread jvmShutdownHook) {
+        this.registry = Objects.requireNonNull(registry);
+        this.addressesToInitializers = Collections.unmodifiableMap(new LinkedHashMap<>(addressesToInitializers));
+        this.serverStatusManager = checkNotNull(serverStatusManager, "serverStatusManager");
+        this.clientConnectionsShutdown = checkNotNull(clientConnectionsShutdown, "clientConnectionsShutdown");
+        this.eventLoopConfig = checkNotNull(eventLoopConfig, "eventLoopConfig");
+        this.eventLoopGroupMetrics = checkNotNull(eventLoopGroupMetrics, "eventLoopGroupMetrics");
+        this.jvmShutdownHook = jvmShutdownHook;
+    }
+
+
     public void stop() {
         LOG.info("Shutting down Zuul.");
         serverGroup.stop();
-
-        // remove the shutdown hook that was added when the proxy was started, since it has now been stopped
-        try {
-            Runtime.getRuntime().removeShutdownHook(jvmShutdownHook);
-        } catch (IllegalStateException e) {
-            // This can happen if the VM is already shutting down
-            LOG.debug("Failed to remove shutdown hook", e);
-        }
         LOG.info("Completed zuul shutdown.");
     }
 
-    public void start()
-    {
+    public void start() {
+        if(jvmShutdownHook != null) {
+            Runtime.getRuntime().addShutdownHook(jvmShutdownHook);
+        }
+
         serverGroup = new ServerGroup(
                 "Salamander", eventLoopConfig.acceptorCount(), eventLoopConfig.eventLoopCount(), eventLoopGroupMetrics);
         serverGroup.initializeTransport();
@@ -317,7 +328,6 @@ private final class ServerGroup
         private final int acceptorThreads;
         private final int workerThreads;
         private final EventLoopGroupMetrics eventLoopGroupMetrics;
-        private final Thread jvmShutdownHook = new Thread(this::stop, "Zuul-ServerGroup-JVM-shutdown-hook");
 
         private EventLoopGroup clientToProxyBossPool;
         private EventLoopGroup clientToProxyWorkerPool;
@@ -337,8 +347,6 @@ public void uncaughtException(final Thread t, final Throwable e) {
                     LOG.error("Uncaught throwable", e);
                 }
             });
-
-            Runtime.getRuntime().addShutdownHook(jvmShutdownHook);
         }
 
         private void initializeTransport()
@@ -446,12 +454,6 @@ synchronized private void stop()
                     LOG.warn("Interrupted while shutting down event loop");
                 }
             }
-            try {
-                Runtime.getRuntime().removeShutdownHook(jvmShutdownHook);
-            } catch (IllegalStateException e) {
-                // This can happen if the VM is already shutting down
-                LOG.debug("Failed to remove shutdown hook", e);
-            }
 
             stopped = true;
             LOG.info("Done shutting down");