我有一个用 Java 编写的服务器 - （在 REQ-REP 和 PUB-SUB 模式中使用 ZeroMQ。）我使用 Apache Commons Daemon (prunsrv/procrun) 将它包装为 Windows 服务
有时对 ZContext.destroy 的调用会挂起。当上下文没有被破坏时，我已经设法获得堆栈跟踪。如果我理解正确， ZContext.destroy() 应该管理所有套接字的终止。可能是什么问题呢？
我已经粘贴了上下文没有被破坏时收到的堆栈跟踪 - 但我们必须结束该过程。
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.zeromq.ZContext;
import org.zeromq.ZMQ;
/**
* This is the driver for starting and stopping the PowerLoggerService
*
*/
public class PowerLoggerService {
static PreferenceManager prefMgr;
static ModuleServer moduleServer;
static DiscoveryServer discoveryServer;
static LoggerRequestServer loggerRequestServer;
static NotificationServer notificationServer;
static ScheduledExecutorService scheduler;
static ZContext zContext;
private static final Logger log = LoggerFactory.getLogger("PowerLoggerService");
private volatile static boolean shouldStop;
private volatile static boolean contextWasDestroyed = false;
public static void start(String [] args) {
zContext = new ZContext();
zContext.setLinger(0);
scheduler = Executors.newScheduledThreadPool(1);
log.trace("Entered startPMServer");
notificationServer = new NotificationServer(zContext);
notificationServer.publishStatus(MessageType.STARTED, "Server started");
if(prefMgr.ensureValidDBPrefs()) {
moduleServer = new ModuleServer();
moduleServer.start();
discoveryServer = new DiscoveryServer();
discoveryServer.start();
loggerRequestServer = new LoggerRequestServer(zContext);
loggerRequestServer.start();
scheduler.scheduleAtFixedRate(notificationServer, 0, 10, TimeUnit.SECONDS);
}
else {
log.error("Could not ensure that we have valid DB preferences ... need to exit.");
System.exit(1);
}
while(!PowerLoggerService.shouldStop){
log.trace("Value of boolean stop in start function: {}", PowerLoggerService.shouldStop);
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
log.error("PowerLoggerService main thread interrupted while sleeping");
}
log.trace("PowerLoggerService is running.");
//printAllStackTraces();
}
//Sometimes the ZContext is not destroyed and the process goes to STOP_PENDING
//the root cause needs to be found out and fixed - for now we are brute forcing
//a System.exit
if(contextWasDestroyed == false) {
log.error("The context was not destroyed cleanly so we are doing a forced exit");
printAllStackTraces();
System.exit(-1);
}
log.debug("Stop was set to true and we are now exiting the start function!");
}
private static void printAllStackTraces() {
StringBuilder sb = new StringBuilder();
log.trace("=========================START TRACE");
Map liveThreads = Thread.getAllStackTraces();
sb.append("\n");
for (Iterator i = liveThreads.keySet().iterator(); i.hasNext(); ) {
Thread key = (Thread)i.next();
sb.append("==============>Thread ").append(key.getName()).append("\n");
StackTraceElement[] trace = (StackTraceElement[])liveThreads.get(key);
for (StackTraceElement trace1 : trace) {
sb.append("\tat ").append(trace1).append("\n");
}
}
log.trace(sb.toString());
log.trace("=========================END TRACE");
}
public static void stop() {
try {
log.info("Going to stop the PowerLoggerService");
discoveryServer.shutDown();
moduleServer.shutDown();
loggerRequestServer.shutDown();
notificationServer.shutDown();
log.trace("In stop method after shutting down notification server");
scheduler.shutdown();
try {
log.trace("Terminated ?: {}",scheduler.awaitTermination(3, TimeUnit.SECONDS));
} catch (InterruptedException ex) {
log.error("Interrupted when awaiting termination",ex);
}
List<Runnable> waiters = scheduler.shutdownNow();
log.debug("Notification scheduled tasks that were waiting to be cancelled: {}", waiters.size());
log.debug("Going to destroy the context");
log.trace("going to set stop to true");
PowerLoggerService.shouldStop = true;
log.trace("stop is set to {}", PowerLoggerService.shouldStop);
//printAllStackTraces();
zContext.destroy();
contextWasDestroyed = true;
log.trace("AFTER context is destroyed");
}
catch (Exception e) {
log.error("Unhandled exception when trying to shut down server ... We are going to have an unclean exit", e);
PowerLoggerService.shouldStop = true;
}
log.trace("Value of stop is set to {}", PowerLoggerService.shouldStop);
}
static void main(String [] args) {
String mode = args[0];
prefMgr = PreferenceManager.getInstance();
if(null != mode) switch (mode) {
case "start":
PowerLoggerService.shouldStop = false;
start(args);
log.trace("Exiting the service start method");
break;
case "stop":
stop();
log.debug("Got request for shutting down service");
break;
}
}
public static void logErrorAndStop(String message) {
notificationServer.publishStatus(MessageType.ERROR,message);
stop();
}
}
给出以下跟踪：
2014-08-07 14:02:27,TRACE,PowerLoggerService,PowerLoggerService.java,101,k.c.p.p.PowerLoggerService,printAllStackTraces
==============>Thread reaper-1
at sun.nio.ch.WindowsSelectorImpl$SubSelector.poll0(Native Method)
at sun.nio.ch.WindowsSelectorImpl$SubSelector.poll(Unknown Source)
at sun.nio.ch.WindowsSelectorImpl$SubSelector.access$400(Unknown Source)
at sun.nio.ch.WindowsSelectorImpl.doSelect(Unknown Source)
at sun.nio.ch.SelectorImpl.lockAndDoSelect(Unknown Source)
at sun.nio.ch.SelectorImpl.select(Unknown Source)
at zmq.Poller.run(Poller.java:207)
at java.lang.Thread.run(Unknown Source)
==============>Thread Finalizer
at java.lang.Object.wait(Native Method)
at java.lang.ref.ReferenceQueue.remove(Unknown Source)
at java.lang.ref.ReferenceQueue.remove(Unknown Source)
at java.lang.ref.Finalizer$FinalizerThread.run(Unknown Source)
==============>Thread iothread-2
at sun.nio.ch.WindowsSelectorImpl$SubSelector.poll0(Native Method)
at sun.nio.ch.WindowsSelectorImpl$SubSelector.poll(Unknown Source)
at sun.nio.ch.WindowsSelectorImpl$SubSelector.access$400(Unknown Source)
at sun.nio.ch.WindowsSelectorImpl.doSelect(Unknown Source)
at sun.nio.ch.SelectorImpl.lockAndDoSelect(Unknown Source)
at sun.nio.ch.SelectorImpl.select(Unknown Source)
at zmq.Poller.run(Poller.java:207)
at java.lang.Thread.run(Unknown Source)
==============>Thread main
at java.lang.Thread.dumpThreads(Native Method)
at java.lang.Thread.getAllStackTraces(Unknown Source)
at kr.co.powermanager.powerlogger.PowerLoggerService.printAllStackTraces(PowerLoggerService.java:89)
at kr.co.powermanager.powerlogger.PowerLoggerService.start(PowerLoggerService.java:79)
at kr.co.powermanager.powerlogger.PowerLoggerService.main(PowerLoggerService.java:148)
==============>Thread Signal Dispatcher
==============>Thread Attach Listener
==============>Thread Thread-3
at sun.nio.ch.WindowsSelectorImpl$SubSelector.poll0(Native Method)
at sun.nio.ch.WindowsSelectorImpl$SubSelector.poll(Unknown Source)
at sun.nio.ch.WindowsSelectorImpl$SubSelector.access$400(Unknown Source)
at sun.nio.ch.WindowsSelectorImpl.doSelect(Unknown Source)
at sun.nio.ch.SelectorImpl.lockAndDoSelect(Unknown Source)
at sun.nio.ch.SelectorImpl.select(Unknown Source)
at zmq.Signaler.wait_event(Signaler.java:135)
at zmq.Mailbox.recv(Mailbox.java:105)
at zmq.SocketBase.process_commands(SocketBase.java:793)
at zmq.SocketBase.recv(SocketBase.java:714)
at org.zeromq.ZMQ$Socket.recv(ZMQ.java:1247)
at org.zeromq.ZMQ$Socket.recv(ZMQ.java:1235)
at kr.co.powermanager.powerlogger.LoggerRequestServer.run(LoggerRequestServer.java:45)
==============>Thread Thread-4
at sun.nio.ch.WindowsSelectorImpl$SubSelector.poll0(Native Method)
at sun.nio.ch.WindowsSelectorImpl$SubSelector.poll(Unknown Source)
at sun.nio.ch.WindowsSelectorImpl$SubSelector.access$400(Unknown Source)
at sun.nio.ch.WindowsSelectorImpl.doSelect(Unknown Source)
at sun.nio.ch.SelectorImpl.lockAndDoSelect(Unknown Source)
at sun.nio.ch.SelectorImpl.select(Unknown Source)
at zmq.Signaler.wait_event(Signaler.java:135)
at zmq.Mailbox.recv(Mailbox.java:105)
at zmq.Ctx.terminate(Ctx.java:190)
at org.zeromq.ZMQ$Context.term(ZMQ.java:301)
at org.zeromq.ZContext.destroy(ZContext.java:98)
at kr.co.powermanager.powerlogger.PowerLoggerService.stop(PowerLoggerService.java:129)
at kr.co.powermanager.powerlogger.PowerLoggerService.main(PowerLoggerService.java:152)
==============>Thread Reference Handler
at java.lang.Object.wait(Native Method)
at java.lang.Object.wait(Unknown Source)
at java.lang.ref.Reference$ReferenceHandler.run(Unknown Source)
2014-08-07 14:02:27,TRACE,PowerLoggerService,PowerLoggerService.java,102,k.c.p.p.PowerLoggerService,printAllStackTraces =========================END TRACE