聊聊artemis的gracefulShutdownEnabled

• Z时代
• 2024-01-10
• 分类：综合

gracefulShutdownEnabled

activemq-artemis-2.11.0/artemis-server/src/main/java/org/apache/activemq/artemis/core/config/impl/ConfigurationImpl.java

public class ConfigurationImpl implements Configuration, Serializable {
   //......
   private boolean gracefulShutdownEnabled = ActiveMQDefaultConfiguration.isDefaultGracefulShutdownEnabled();
   private long gracefulShutdownTimeout = ActiveMQDefaultConfiguration.getDefaultGracefulShutdownTimeout();
   //......
   @Override
   public boolean isGracefulShutdownEnabled() {
      return gracefulShutdownEnabled;
   }
   @Override
   public ConfigurationImpl setGracefulShutdownEnabled(final boolean enabled) {
      gracefulShutdownEnabled = enabled;
      return this;
   }
   @Override
   public long getGracefulShutdownTimeout() {
      return gracefulShutdownTimeout;
   }
   @Override
   public ConfigurationImpl setGracefulShutdownTimeout(final long timeout) {
      gracefulShutdownTimeout = timeout;
      return this;
   }
   //......
}

• ConfigurationImpl定义了两个关于gracefulShutdown的属性，分别是gracefulShutdownEnabled(默认为true)及gracefulShutdownTimeout(默认为-1)

ActiveMQServerImpl

activemq-artemis-2.11.0/artemis-server/src/main/java/org/apache/activemq/artemis/core/server/impl/ActiveMQServerImpl.java

public class ActiveMQServerImpl implements ActiveMQServer {
   //......
   public final void stop(boolean failoverOnServerShutdown, boolean isExit) throws Exception {
      stop(failoverOnServerShutdown, false, false, isExit);
   }
   public void stop(boolean failoverOnServerShutdown, final boolean criticalIOError, boolean restarting) {
      this.stop(failoverOnServerShutdown, criticalIOError, restarting, false);
   }
   void stop(boolean failoverOnServerShutdown, final boolean criticalIOError, boolean restarting, boolean isShutdown) {
      logger.debug("Stopping server");
      synchronized (this) {
         if (state == SERVER_STATE.STOPPED || state == SERVER_STATE.STOPPING) {
            return;
         }
         state = SERVER_STATE.STOPPING;
         if (fileStoreMonitor != null) {
            fileStoreMonitor.stop();
            fileStoreMonitor = null;
         }
         if (failoverOnServerShutdown) {
            activation.sendLiveIsStopping();
         }
         stopComponent(connectorsService);
         // we stop the groupingHandler before we stop the cluster manager so binding mappings
         // aren"t removed in case of failover
         if (groupingHandler != null) {
            managementService.removeNotificationListener(groupingHandler);
            stopComponent(groupingHandler);
         }
         stopComponent(federationManager);
         stopComponent(clusterManager);
         if (remotingService != null) {
            remotingService.pauseAcceptors();
         }
         // allows for graceful shutdown
         if (remotingService != null && configuration.isGracefulShutdownEnabled()) {
            long timeout = configuration.getGracefulShutdownTimeout();
            try {
               if (timeout == -1) {
                  remotingService.getConnectionCountLatch().await();
               } else {
                  remotingService.getConnectionCountLatch().await(timeout);
               }
            } catch (InterruptedException e) {
               ActiveMQServerLogger.LOGGER.interruptWhilstStoppingComponent(remotingService.getClass().getName());
            }
         }
         freezeConnections();
      }
      //......
    }
   static void stopComponent(ActiveMQComponent component) {
      try {
         if (component != null) {
            component.stop();
         }
      } catch (Throwable t) {
         ActiveMQServerLogger.LOGGER.errorStoppingComponent(t, component.getClass().getName());
      }
   }
   //......
}    

• ActiveMQServerImpl在remotingService不为null且configuration.isGracefulShutdownEnabled()为true时会读取configuration.getGracefulShutdownTimeout()；若timeout为-1，则执行remotingService.getConnectionCountLatch().await()，否则执行remotingService.getConnectionCountLatch().await(timeout)

connectionCountLatch

activemq-artemis-2.11.0/artemis-server/src/main/java/org/apache/activemq/artemis/core/remoting/server/impl/RemotingServiceImpl.java

public class RemotingServiceImpl implements RemotingService, ServerConnectionLifeCycleListener {
   //......
   private final ReusableLatch connectionCountLatch = new ReusableLatch(0);
   //......
   public synchronized ReusableLatch getConnectionCountLatch() {
      return connectionCountLatch;
   }
   public void connectionCreated(final ActiveMQComponent component,
                                 final Connection connection,
                                 final ProtocolManager protocol) {
      if (server == null) {
         throw new IllegalStateException("Unable to create connection, server hasn"t finished starting up");
      }
      ConnectionEntry entry = protocol.createConnectionEntry((Acceptor) component, connection);
      try {
         if (server.hasBrokerConnectionPlugins()) {
            server.callBrokerConnectionPlugins(plugin -> plugin.afterCreateConnection(entry.connection));
         }
      } catch (ActiveMQException t) {
         logger.warn("Error executing afterCreateConnection plugin method: {}", t.getMessage(), t);
         throw new IllegalStateException(t.getMessage(), t.getCause());
      }
      if (logger.isTraceEnabled()) {
         logger.trace("Connection created " + connection);
      }
      connections.put(connection.getID(), entry);
      connectionCountLatch.countUp();
      totalConnectionCount.incrementAndGet();
   }
   public RemotingConnection removeConnection(final Object remotingConnectionID) {
      ConnectionEntry entry = connections.remove(remotingConnectionID);
      if (entry != null) {
         logger.debug("RemotingServiceImpl::removing connection ID " + remotingConnectionID);
         connectionCountLatch.countDown();
         return entry.connection;
      } else {
         logger.debug("The connectionID::" + remotingConnectionID + " was already removed by some other module");
         return null;
      }
   }
   //......
}         

• getConnectionCountLatch返回的是connectionCountLatch；connectionCreated方法会执行connectionCountLatch.countUp()；removeConnection方法会执行connectionCountLatch.countDown()

小结

ConfigurationImpl定义了两个关于gracefulShutdown的属性，分别是gracefulShutdownEnabled(默认为true)及gracefulShutdownTimeout(默认为-1)；ActiveMQServerImpl在remotingService不为null且configuration.isGracefulShutdownEnabled()为true时会读取configuration.getGracefulShutdownTimeout()；若timeout为-1，则执行remotingService.getConnectionCountLatch().await()，否则执行remotingService.getConnectionCountLatch().await(timeout)

doc

• ConfigurationImpl

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