| /* |
| * Copyright 2014-2015 Open Networking Laboratory |
| * |
| * Licensed 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.onosproject.event.impl; |
| |
| import org.apache.felix.scr.annotations.Activate; |
| import org.apache.felix.scr.annotations.Component; |
| import org.apache.felix.scr.annotations.Deactivate; |
| import org.apache.felix.scr.annotations.Service; |
| import org.onlab.util.SharedExecutors; |
| import org.onosproject.event.AbstractEvent; |
| import org.onosproject.event.DefaultEventSinkRegistry; |
| import org.onosproject.event.Event; |
| import org.onosproject.event.EventDeliveryService; |
| import org.onosproject.event.EventSink; |
| import org.slf4j.Logger; |
| |
| import java.util.TimerTask; |
| import java.util.concurrent.BlockingQueue; |
| import java.util.concurrent.ExecutorService; |
| import java.util.concurrent.Future; |
| import java.util.concurrent.LinkedBlockingQueue; |
| |
| import static com.google.common.base.Preconditions.checkArgument; |
| import static java.util.concurrent.Executors.newSingleThreadExecutor; |
| import static org.onlab.util.Tools.groupedThreads; |
| import static org.slf4j.LoggerFactory.getLogger; |
| |
| /** |
| * Simple implementation of an event dispatching service. |
| */ |
| @Component(immediate = true) |
| @Service |
| public class CoreEventDispatcher extends DefaultEventSinkRegistry |
| implements EventDeliveryService { |
| |
| private final Logger log = getLogger(getClass()); |
| |
| // Default number of millis a sink can take to process an event. |
| private static final long DEFAULT_EXECUTE_MS = 5_000; // ms |
| private static final long WATCHDOG_MS = 250; // ms |
| |
| private final BlockingQueue<Event> events = new LinkedBlockingQueue<>(); |
| |
| private final ExecutorService executor = |
| newSingleThreadExecutor(groupedThreads("onos/event", "dispatch-%d")); |
| |
| @SuppressWarnings("unchecked") |
| private static final Event KILL_PILL = new AbstractEvent(null, 0) { |
| }; |
| |
| private DispatchLoop dispatchLoop; |
| private long maxProcessMillis = DEFAULT_EXECUTE_MS; |
| |
| // Means to detect long-running sinks |
| private TimerTask watchdog; |
| private EventSink lastSink; |
| private long lastStart = 0; |
| private Future<?> dispatchFuture; |
| |
| @Override |
| public void post(Event event) { |
| if (!events.add(event)) { |
| log.error("Unable to post event {}", event); |
| } |
| } |
| |
| @Activate |
| public void activate() { |
| dispatchLoop = new DispatchLoop(); |
| dispatchFuture = executor.submit(dispatchLoop); |
| watchdog = new Watchdog(); |
| SharedExecutors.getTimer().schedule(watchdog, WATCHDOG_MS, WATCHDOG_MS); |
| log.info("Started"); |
| } |
| |
| @Deactivate |
| public void deactivate() { |
| dispatchLoop.stop(); |
| watchdog.cancel(); |
| post(KILL_PILL); |
| log.info("Stopped"); |
| } |
| |
| @Override |
| public void setDispatchTimeLimit(long millis) { |
| checkArgument(millis >= WATCHDOG_MS, |
| "Time limit must be greater than %s", WATCHDOG_MS); |
| maxProcessMillis = millis; |
| } |
| |
| @Override |
| public long getDispatchTimeLimit() { |
| return maxProcessMillis; |
| } |
| |
| // Auxiliary event dispatching loop that feeds off the events queue. |
| private class DispatchLoop implements Runnable { |
| private volatile boolean stopped; |
| |
| @Override |
| public void run() { |
| stopped = false; |
| log.info("Dispatch loop initiated"); |
| while (!stopped) { |
| try { |
| // Fetch the next event and if it is the kill-pill, bail |
| Event event = events.take(); |
| if (event == KILL_PILL) { |
| break; |
| } |
| process(event); |
| } catch (InterruptedException e) { |
| log.warn("Dispatch loop interrupted"); |
| } catch (Exception | Error e) { |
| log.warn("Error encountered while dispatching event:", e); |
| } |
| } |
| log.info("Dispatch loop terminated"); |
| } |
| |
| // Locate the sink for the event class and use it to process the event |
| @SuppressWarnings("unchecked") |
| private void process(Event event) { |
| EventSink sink = getSink(event.getClass()); |
| if (sink != null) { |
| lastSink = sink; |
| lastStart = System.currentTimeMillis(); |
| sink.process(event); |
| lastStart = 0; |
| } else { |
| log.warn("No sink registered for event class {}", |
| event.getClass().getName()); |
| } |
| } |
| |
| void stop() { |
| stopped = true; |
| } |
| } |
| |
| // Monitors event sinks to make sure none take too long to execute. |
| private class Watchdog extends TimerTask { |
| @Override |
| public void run() { |
| long delta = System.currentTimeMillis() - lastStart; |
| if (lastStart > 0 && delta > maxProcessMillis) { |
| lastStart = 0; |
| log.warn("Event sink {} exceeded execution time limit: {} ms; spawning new dispatch loop", |
| lastSink.getClass().getName(), delta); |
| |
| // Notify the sink that it has exceeded its time limit. |
| lastSink.onProcessLimit(); |
| |
| // Cancel the old dispatch loop and submit a new one. |
| dispatchLoop.stop(); |
| dispatchLoop = new DispatchLoop(); |
| dispatchFuture.cancel(true); |
| dispatchFuture = executor.submit(dispatchLoop); |
| } |
| } |
| } |
| } |