Java Code Examples for org.apache.zookeeper.KeeperException#SessionExpiredException

@Override
public void abort(String why,Throwable e){
    if(e instanceof KeeperException.SessionExpiredException){
        try{
            LOG.info("Lost connection with ZooKeeper, attempting reconnect");
            watcher=null;
            initialize(HConfiguration.getConfiguration());
            LOG.info("Successfully reconnected to ZooKeeper");
        }catch(RuntimeException zce){
            LOG.error("Could not reconnect to zookeeper after session expiration, aborting");
            e=zce;
        }
    }
    if(e!=null)
        LOG.error(why,e);
    else
        LOG.error(why);
    this.isAborted=true;
}
 

private void handleSessionExpiredError(Throwable error) {
    if (!(error instanceof KeeperException.SessionExpiredException)) {
        return;
    }
    try {
        restartZooKeeper();
    } catch (IOException | InterruptedException err) {
        LOGGER.log(Level.SEVERE, "Error handling session expired", err);
    }
}
 

@Test
public void testSessionExpired() throws Exception {
    try (ZookeeperMetadataStorageManager man = new ZookeeperMetadataStorageManager(testEnv.getAddress(),
            testEnv.getTimeout(), testEnv.getPath())) {
        man.start();

        TableSpace tableSpace = TableSpace
                .builder()
                .leader("test")
                .replica("test")
                .name(TableSpace.DEFAULT)
                .build();
        man.registerTableSpace(tableSpace);
        assertEquals(1, man.listTableSpaces().size());
        ZooKeeper actual = man.getZooKeeper();
        long sessionId = actual.getSessionId();
        byte[] passwd = actual.getSessionPasswd();
        expireZkSession(sessionId, passwd);
        for (int i = 0; i < 10; i++) {
            try {
                man.listTableSpaces();
                fail("session should be expired or not connected");
            } catch (MetadataStorageManagerException ok) {
                System.out.println("ok: " + ok);
                assertTrue(ok.getCause() instanceof KeeperException.ConnectionLossException
                        || ok.getCause() instanceof KeeperException.SessionExpiredException);
                if (ok.getCause() instanceof KeeperException.SessionExpiredException) {
                    break;
                }
            }
            Thread.sleep(500);
        }
        assertNotSame(actual, man.getZooKeeper());
        assertEquals(1, man.listTableSpaces().size());

        assertNotNull(tableSpace = man.describeTableSpace(TableSpace.DEFAULT));
        man.dropTableSpace(TableSpace.DEFAULT, tableSpace);
    }
}
 

private boolean areAllReplicasParticipating() throws InterruptedException {
  final String shardsElectZkPath = electionPath + LeaderElector.ELECTION_NODE;
  final DocCollection docCollection = zkController.getClusterState().getCollectionOrNull(collection);

  if (docCollection != null && docCollection.getSlice(shardId) != null) {
    final Slice slices = docCollection.getSlice(shardId);
    int found = 0;
    try {
      found = zkClient.getChildren(shardsElectZkPath, null, true).size();
    } catch (KeeperException e) {
      if (e instanceof KeeperException.SessionExpiredException) {
        // if the session has expired, then another election will be launched, so
        // quit here
        throw new SolrException(ErrorCode.SERVER_ERROR,
            "ZK session expired - cancelling election for " + collection + " " + shardId);
      }
      SolrException.log(log, "Error checking for the number of election participants", e);
    }

    if (found >= slices.getReplicasMap().size()) {
      log.debug("All replicas are ready to participate in election.");
      return true;
    }
  } else {
    log.warn("Shard not found: {} for collection {}", shardId, collection);
    return false;
  }
  return false;
}
 

@Override
public boolean allowRetry(Throwable exception)
{
    if ( exception instanceof KeeperException.SessionExpiredException )
    {
        return false;
    }
    else
    {
        return delegatePolicy.allowRetry(exception);
    }
}
 

public <T> T execute(Command<T> command) throws InterruptedException, KeeperException{
    try{
        return command.execute(getRecoverableZooKeeper());
    }catch(ZooKeeperConnectionException e){
        throw new KeeperException.SessionExpiredException();
    }
}
 

private boolean waitForReplicasToComeUp(int timeoutms) throws InterruptedException {
  long timeoutAt = System.nanoTime() + TimeUnit.NANOSECONDS.convert(timeoutms, TimeUnit.MILLISECONDS);
  final String shardsElectZkPath = electionPath + LeaderElector.ELECTION_NODE;

  DocCollection docCollection = zkController.getClusterState().getCollectionOrNull(collection);
  Slice slices = (docCollection == null) ? null : docCollection.getSlice(shardId);
  int cnt = 0;
  while (!isClosed && !cc.isShutDown()) {
    // wait for everyone to be up
    if (slices != null) {
      int found = 0;
      try {
        found = zkClient.getChildren(shardsElectZkPath, null, true).size();
      } catch (KeeperException e) {
        if (e instanceof KeeperException.SessionExpiredException) {
          // if the session has expired, then another election will be launched, so
          // quit here
          throw new SolrException(ErrorCode.SERVER_ERROR,
              "ZK session expired - cancelling election for " + collection + " " + shardId);
        }
        SolrException.log(log,
            "Error checking for the number of election participants", e);
      }

      // on startup and after connection timeout, wait for all known shards
      if (found >= slices.getReplicas(EnumSet.of(Replica.Type.TLOG, Replica.Type.NRT)).size()) {
        log.info("Enough replicas found to continue.");
        return true;
      } else {
        if (cnt % 40 == 0) {
          if (log.isInfoEnabled()) {
            log.info("Waiting until we see more replicas up for shard {}: total={} found={} timeoute in={}ms"
                , shardId, slices.getReplicas(EnumSet.of(Replica.Type.TLOG, Replica.Type.NRT)).size(), found,
                TimeUnit.MILLISECONDS.convert(timeoutAt - System.nanoTime(), TimeUnit.NANOSECONDS));
          }
        }
      }

      if (System.nanoTime() > timeoutAt) {
        log.info("Was waiting for replicas to come up, but they are taking too long - assuming they won't come back till later");
        return false;
      }
    } else {
      log.warn("Shard not found: {} for collection {}", shardId, collection);

      return false;

    }

    Thread.sleep(500);
    docCollection = zkController.getClusterState().getCollectionOrNull(collection);
    slices = (docCollection == null) ? null : docCollection.getSlice(shardId);
    cnt++;
  }
  return false;
}
 

public <T> T executeUnlessExpired(Command<T> command) throws InterruptedException, KeeperException{
    /*
     * What actually happens is that, in the event of a long network partition, ZooKeeper will throw
     * ConnectionLoss exceptions, but it will NOT throw a SessionExpired exception until it reconnects, even
     * if it's been disconnected for CLEARLY longer than the session timeout.
     *
     * To deal with this, we have to basically loop through our command repeatedly until we either
     *
     * 1. Succeed.
     * 2. Get a SessionExpired event from ZooKeeper
     * 3. Spent more than 2*sessionTimeout ms attempting the request
     * 4. Get some other kind of Zk error (NoNode, etc).
     */
    RecoverableZooKeeper rzk;
    try{
        rzk=getRecoverableZooKeeper();
    }catch(ZooKeeperConnectionException e){
        throw new KeeperException.SessionExpiredException();
    }
    //multiple by 2 to make absolutely certain we're timed out.
    int sessionTimeout=2*rzk.getZooKeeper().getSessionTimeout();
    long nextTime=System.currentTimeMillis();
    long startTime=System.currentTimeMillis();
    while((int)(nextTime-startTime)<sessionTimeout){
        try{
            return command.execute(rzk);
        }catch(KeeperException ke){
            switch(ke.code()){
                case CONNECTIONLOSS:
                case OPERATIONTIMEOUT:
                    LOG.warn("Detected a Connection issue("+ke.code()+") with ZooKeeper, retrying");
                    nextTime=System.currentTimeMillis();
                    break;
                default:
                    throw ke;
            }
        }
    }

    //we've run out of time, our session has almost certainly expired. Give up and explode
    throw new KeeperException.SessionExpiredException();
}