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

/**
 * Tries to delete empty parent znodes.
 *
 * <p>IMPORTANT: This method can be removed once all supported ZooKeeper versions
 * support the container {@link org.apache.zookeeper.CreateMode}.
 *
 * @throws Exception if the deletion fails for other reason than {@link KeeperException.NotEmptyException}
 */
private void tryDeleteEmptyParentZNodes() throws Exception {
	// try to delete the parent znodes if they are empty
	String remainingPath = getParentPath(getNormalizedPath(client.getNamespace()));
	final CuratorFramework nonNamespaceClient = client.usingNamespace(null);

	while (!isRootPath(remainingPath)) {
		try {
			nonNamespaceClient.delete().forPath(remainingPath);
		} catch (KeeperException.NotEmptyException ignored) {
			// We can only delete empty znodes
			break;
		}

		remainingPath = getParentPath(remainingPath);
	}
}
 

/**
 * Tries to delete empty parent znodes.
 *
 * <p>IMPORTANT: This method can be removed once all supported ZooKeeper versions
 * support the container {@link org.apache.zookeeper.CreateMode}.
 *
 * @throws Exception if the deletion fails for other reason than {@link KeeperException.NotEmptyException}
 */
private void tryDeleteEmptyParentZNodes() throws Exception {
	// try to delete the parent znodes if they are empty
	String remainingPath = getParentPath(getNormalizedPath(client.getNamespace()));
	final CuratorFramework nonNamespaceClient = client.usingNamespace(null);

	while (!isRootPath(remainingPath)) {
		try {
			nonNamespaceClient.delete().forPath(remainingPath);
		} catch (KeeperException.NotEmptyException ignored) {
			// We can only delete empty znodes
			break;
		}

		remainingPath = getParentPath(remainingPath);
	}
}
 

private void deleteBranch(final String key) throws KeeperException, InterruptedException {
    deleteChildren(key, false);
    Stack<String> pathStack = getProvider().getDeletingPaths(key);
    while (!pathStack.empty()) {
        String node = pathStack.pop();
        // contrast cache
        if (getProvider().exists(node)) {
            try {
                getProvider().delete(node);
            } catch (KeeperException.NotEmptyException e) {
                log.warn("deleteBranch {} exist other children: {}", node, this.getChildren(node));
                return;
            }
        }
        log.info("deleteBranch node not exist: {}", node);
    }
}
 

/**
 * Deletes the given ZK path.
 *
 * @param path path to delete
 * @return true if the path was deleted, false if failed to delete due to {@link KeeperException.NotEmptyException}.
 * @throws Exception if failed to delete the path
 */
private boolean delete(String path) throws Exception {
  try {
    LOG.info("Removing ZK path: {}{}", zkClient.getConnectString(), path);
    zkClient.delete(path).get(TIMEOUT_SECONDS, TimeUnit.SECONDS);
    return true;
  } catch (ExecutionException e) {
    if (e.getCause() instanceof KeeperException.NotEmptyException) {
      return false;
    }
    if (e.getCause() instanceof KeeperException.NoNodeException) {
      // If the node to be deleted was not created or is already gone, it is the same as delete successfully.
      return true;
    }
    throw e;
  }
}
 

/**
 * Delete a path and all of its sub nodes
 * @param filter for node to be deleted
 */
public static void clean(SolrZkClient zkClient, String path, Predicate<String> filter) throws InterruptedException, KeeperException {
  if (filter == null) {
    clean(zkClient, path);
    return;
  }

  TreeSet<String> paths = new TreeSet<>(Comparator.comparingInt(String::length).reversed());

  traverseZkTree(zkClient, path, VISIT_ORDER.VISIT_POST, znode -> {
    if (!znode.equals("/") && filter.test(znode)) paths.add(znode);
  });

  for (String subpath : paths) {
    if (!subpath.equals("/")) {
      try {
        zkClient.delete(subpath, -1, true);
      } catch (KeeperException.NotEmptyException | KeeperException.NoNodeException e) {
        // expected
      }
    }
  }
}
 

/**
 * Releases the lock for the given state node and tries to remove the state node if it is no longer locked.
 * It returns the {@link RetrievableStateHandle} stored under the given state node if any.
 *
 * @param pathInZooKeeper Path of state handle to remove
 * @return True if the state handle could be released
 * @throws Exception If the ZooKeeper operation or discarding the state handle fails
 */
@Nullable
public boolean releaseAndTryRemove(String pathInZooKeeper) throws Exception {
	checkNotNull(pathInZooKeeper, "Path in ZooKeeper");

	final String path = normalizePath(pathInZooKeeper);

	RetrievableStateHandle<T> stateHandle = null;

	try {
		stateHandle = get(path, false);
	} catch (Exception e) {
		LOG.warn("Could not retrieve the state handle from node {}.", path, e);
	}

	release(pathInZooKeeper);

	try {
		client.delete().forPath(path);
	} catch (KeeperException.NotEmptyException ignored) {
		LOG.debug("Could not delete znode {} because it is still locked.", path);
		return false;
	}

	if (stateHandle != null) {
		stateHandle.discardState();
	}

	return true;
}
 

/**
 * Releases the lock for the given state node and tries to remove the state node if it is no longer locked.
 * It returns the {@link RetrievableStateHandle} stored under the given state node if any.
 *
 * @param pathInZooKeeper Path of state handle to remove
 * @return True if the state handle could be released
 * @throws Exception If the ZooKeeper operation or discarding the state handle fails
 */
public boolean releaseAndTryRemove(String pathInZooKeeper) throws Exception {
	checkNotNull(pathInZooKeeper, "Path in ZooKeeper");

	final String path = normalizePath(pathInZooKeeper);

	RetrievableStateHandle<T> stateHandle = null;

	try {
		stateHandle = get(path, false);
	} catch (Exception e) {
		LOG.warn("Could not retrieve the state handle from node {}.", path, e);
	}

	release(pathInZooKeeper);

	try {
		client.delete().forPath(path);
	} catch (KeeperException.NotEmptyException ignored) {
		LOG.debug("Could not delete znode {} because it is still locked.", path);
		return false;
	}

	if (stateHandle != null) {
		stateHandle.discardState();
	}

	return true;
}
 

protected final void deleteNamespace() throws KeeperException, InterruptedException {
    try {
        holder.getZooKeeper().delete(rootNode, ZookeeperConstants.VERSION);
    } catch (final KeeperException.NodeExistsException | KeeperException.NotEmptyException ex) {
        log.info("delete root :{}", ex.getMessage());
    }
    rootExist = false;
}
 

private void deleteRecursively(final String path) throws KeeperException, InterruptedException {
    int index = path.lastIndexOf(ZookeeperConstants.PATH_SEPARATOR);
    if (index == 0) {
        deleteOnlyCurrent(path);
        return;
    }
    String superPath = path.substring(0, index);
    try {
        deleteOnlyCurrent(path);
        deleteRecursively(superPath);
    } catch (final KeeperException.NotEmptyException ex) {
        log.info("deleteRecursively exist children: {}, ex: {}", path, ex.getMessage());
    }
}
 

public void run() {
    try {
        List<String> list = client.getChildren().forPath(path);
        if (list == null || list.isEmpty()) {
            client.delete().forPath(path);
        }
    } catch (KeeperException.NoNodeException e1) {
        //nothing
    } catch (KeeperException.NotEmptyException e2) {
        //nothing
    } catch (Exception e) {
        log.error(e.getMessage(), e);//准备删除时,正好有线程创建锁
    }
}
 

public void run() {
    try {
        List list = client.getChildren().forPath(path);
        if (list == null || list.isEmpty()) {
            client.delete().forPath(path);
        }
    } catch (KeeperException.NoNodeException e1) {
        //nothing
    } catch (KeeperException.NotEmptyException e2) {
        //nothing
    } catch (Exception e) {
        log.error(e.getMessage(), e);//准备删除时,正好有线程创建锁
    }
}
 

/** Deletes a node below the given directory root */
private void deleteNode(String pathString, boolean deleteChildren, Node root, Listeners listeners)
        throws KeeperException.NoNodeException, KeeperException.NotEmptyException {
    validatePath(pathString);
    Path path = Path.fromString(pathString);
    Node parent = root.getNode(Paths.get(path.getParentPath().toString()), false);
    if (parent == null) throw new KeeperException.NoNodeException(path.toString());
    Node node = parent.children().get(path.getName());
    if (node == null) throw new KeeperException.NoNodeException(path.getName() + " under " + parent);
    if ( ! node.children().isEmpty() && ! deleteChildren)
        throw new KeeperException.NotEmptyException(path.toString());
    parent.remove(path.getName());
    listeners.notify(path, new byte[0], PathChildrenCacheEvent.Type.CHILD_REMOVED);
}
 

@Override
protected void shutDown() throws Exception {
  super.shutDown();

  // Deletes ZK nodes created for the application execution.
  // We don't have to worry about a race condition if another instance of the same app starts at the same time
  // as when removal is performed. This is because we always create nodes with "createParent == true",
  // which takes care of the parent node recreation if it is removed from here.

  // Try to delete the /instances path. It may throws NotEmptyException if there are other instances of the
  // same app running, which we can safely ignore and return.
  if (!delete(Constants.INSTANCES_PATH_PREFIX)) {
    return;
  }

  // Try to delete children under /discovery. It may fail with NotEmptyException if there are other instances
  // of the same app running that has discovery services running.
  List<String> children = getChildren(Constants.DISCOVERY_PATH_PREFIX);
  List<OperationFuture<?>> deleteFutures = new ArrayList<>();
  for (String child : children) {
    String path = Constants.DISCOVERY_PATH_PREFIX + "/" + child;
    LOG.info("Removing ZK path: {}{}", zkClient.getConnectString(), path);
    deleteFutures.add(zkClient.delete(path));
  }
  Futures.successfulAsList(deleteFutures).get(TIMEOUT_SECONDS, TimeUnit.SECONDS);
  for (OperationFuture<?> future : deleteFutures) {
    try {
      future.get();
    } catch (ExecutionException e) {
      if (e.getCause() instanceof KeeperException.NotEmptyException) {
        // If any deletion of the service failed with not empty, if means there are other apps running,
        // hence just return
        return;
      }
      if (e.getCause() instanceof KeeperException.NoNodeException) {
        // If the service node is gone, it maybe deleted by another app instance that is also shutting down,
        // hence just keep going
        continue;
      }
      throw e;
    }
  }

  // Delete the /discovery. It may fail with NotEmptyException (due to race between apps),
  // which can safely ignore and return.
  if (!delete(Constants.DISCOVERY_PATH_PREFIX)) {
    return;
  }

  // Delete the ZK path for the app namespace.
  delete("/");
}
 

@Override
public void dropInstance(String clusterName, InstanceConfig instanceConfig) {
  logger.info("Drop instance {} from cluster {}.", instanceConfig.getInstanceName(), clusterName);
  String instanceName = instanceConfig.getInstanceName();

  String instanceConfigPath = PropertyPathBuilder.instanceConfig(clusterName, instanceName);
  if (!_zkClient.exists(instanceConfigPath)) {
    throw new HelixException(
        "Node " + instanceName + " does not exist in config for cluster " + clusterName);
  }

  String instancePath = PropertyPathBuilder.instance(clusterName, instanceName);
  if (!_zkClient.exists(instancePath)) {
    throw new HelixException(
        "Node " + instanceName + " does not exist in instances for cluster " + clusterName);
  }

  String liveInstancePath = PropertyPathBuilder.liveInstance(clusterName, instanceName);
  if (_zkClient.exists(liveInstancePath)) {
    throw new HelixException(
        "Node " + instanceName + " is still alive for cluster " + clusterName + ", can't drop.");
  }

  // delete config path
  String instanceConfigsPath = PropertyPathBuilder.instanceConfig(clusterName);
  ZKUtil.dropChildren(_zkClient, instanceConfigsPath, instanceConfig.getRecord());

  // delete instance path
  int retryCnt = 0;
  while (true) {
    try {
      _zkClient.deleteRecursively(instancePath);
      return;
    } catch (ZkClientException e) {
      if (retryCnt < 3 && e.getCause() instanceof ZkException && e.getCause()
          .getCause() instanceof KeeperException.NotEmptyException) {
        // Racing condition with controller's persisting node history, retryable.
        // We don't need to backoff here as this racing condition only happens once (controller
        // does not repeatedly write instance history)
        logger.warn("Retrying dropping instance {} with exception {}",
            instanceConfig.getInstanceName(), e.getCause().getMessage());
        retryCnt++;
      } else {
        String errorMessage = "Failed to drop instance: " + instanceConfig.getInstanceName()
            + ". Retry times: " + retryCnt;
        logger.error(errorMessage, e);
        throw new HelixException(errorMessage, e);
      }
    }
  }
}