| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You 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.apache.solr.handler; |
| |
| import java.lang.invoke.MethodHandles; |
| |
| import org.apache.solr.common.cloud.SolrZkClient; |
| import org.apache.solr.core.SolrCore; |
| import org.apache.zookeeper.CreateMode; |
| import org.apache.zookeeper.KeeperException; |
| import org.apache.zookeeper.WatchedEvent; |
| import org.apache.zookeeper.Watcher; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| /** |
| * <p> |
| * Manage the life-cycle state of the CDCR process. It is responsible of synchronising the state |
| * through Zookeeper. The state of the CDCR process is stored in the zk node defined by {@link #getZnodePath()}. |
| * </p> |
| * <p> |
| * It takes care of notifying the {@link CdcrReplicatorManager} in case |
| * of a process state change. |
| * </p> |
| * @deprecated since 8.6 |
| */ |
| @Deprecated(since = "8.6") |
| class CdcrProcessStateManager extends CdcrStateManager { |
| |
| private CdcrParams.ProcessState state = DEFAULT_STATE; |
| |
| private ProcessStateWatcher wrappedWatcher; |
| private Watcher watcher; |
| |
| private SolrCore core; |
| |
| /** |
| * The default state must be STOPPED. See comments in |
| * {@link #setState(org.apache.solr.handler.CdcrParams.ProcessState)}. |
| */ |
| static CdcrParams.ProcessState DEFAULT_STATE = CdcrParams.ProcessState.STOPPED; |
| |
| private static final Logger log = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass()); |
| |
| CdcrProcessStateManager(final SolrCore core) { |
| this.core = core; |
| |
| // Ensure that the status znode exists |
| this.createStateNode(); |
| |
| // Register the watcher at startup |
| try { |
| SolrZkClient zkClient = core.getCoreContainer().getZkController().getZkClient(); |
| watcher = this.initWatcher(zkClient); |
| this.setState(CdcrParams.ProcessState.get(zkClient.getData(this.getZnodePath(), watcher, null, true))); |
| } catch (KeeperException | InterruptedException e) { |
| log.warn("Failed fetching initial state", e); |
| } |
| } |
| |
| /** |
| * SolrZkClient does not guarantee that a watch object will only be triggered once for a given notification |
| * if we does not wrap the watcher - see SOLR-6621. |
| */ |
| private Watcher initWatcher(SolrZkClient zkClient) { |
| wrappedWatcher = new ProcessStateWatcher(); |
| return zkClient.wrapWatcher(wrappedWatcher); |
| } |
| |
| private String getZnodeBase() { |
| return "/collections/" + core.getCoreDescriptor().getCloudDescriptor().getCollectionName() + "/cdcr/state"; |
| } |
| |
| private String getZnodePath() { |
| return getZnodeBase() + "/process"; |
| } |
| |
| void setState(CdcrParams.ProcessState state) { |
| if (this.state != state) { |
| this.state = state; |
| this.callback(); // notify the observers of a state change |
| } |
| } |
| |
| CdcrParams.ProcessState getState() { |
| return state; |
| } |
| |
| /** |
| * Synchronise the state to Zookeeper. This method must be called only by the handler receiving the |
| * action. |
| */ |
| void synchronize() { |
| SolrZkClient zkClient = core.getCoreContainer().getZkController().getZkClient(); |
| try { |
| zkClient.setData(this.getZnodePath(), this.getState().getBytes(), true); |
| // check if nobody changed it in the meantime, and set a new watcher |
| this.setState(CdcrParams.ProcessState.get(zkClient.getData(this.getZnodePath(), watcher, null, true))); |
| } catch (KeeperException | InterruptedException e) { |
| log.warn("Failed synchronising new state", e); |
| } |
| } |
| |
| private void createStateNode() { |
| SolrZkClient zkClient = core.getCoreContainer().getZkController().getZkClient(); |
| try { |
| if (!zkClient.exists(this.getZnodePath(), true)) { |
| if (!zkClient.exists(this.getZnodeBase(), true)) { // Should be a no-op if the node exists |
| zkClient.makePath(this.getZnodeBase(), null, CreateMode.PERSISTENT, null, false, true); |
| } |
| zkClient.create(this.getZnodePath(), DEFAULT_STATE.getBytes(), CreateMode.PERSISTENT, true); |
| if (log.isInfoEnabled()) { |
| log.info("Created znode {}", this.getZnodePath()); |
| } |
| } |
| } catch (KeeperException.NodeExistsException ne) { |
| // Someone got in first and created the node. |
| } catch (KeeperException | InterruptedException e) { |
| log.warn("Failed to create CDCR process state node", e); |
| } |
| } |
| |
| void shutdown() { |
| if (wrappedWatcher != null) { |
| wrappedWatcher.cancel(); // cancel the watcher to avoid spurious warn messages during shutdown |
| } |
| } |
| |
| private class ProcessStateWatcher implements Watcher { |
| |
| private boolean isCancelled = false; |
| |
| /** |
| * Cancel the watcher to avoid spurious warn messages during shutdown. |
| */ |
| void cancel() { |
| isCancelled = true; |
| } |
| |
| @Override |
| public void process(WatchedEvent event) { |
| if (isCancelled) return; // if the watcher is cancelled, do nothing. |
| String collectionName = core.getCoreDescriptor().getCloudDescriptor().getCollectionName(); |
| String shard = core.getCoreDescriptor().getCloudDescriptor().getShardId(); |
| |
| log.info("The CDCR process state has changed: {} @ {}:{}", event, collectionName, shard); |
| // session events are not change events, and do not remove the watcher |
| if (Event.EventType.None.equals(event.getType())) { |
| return; |
| } |
| SolrZkClient zkClient = core.getCoreContainer().getZkController().getZkClient(); |
| try { |
| CdcrParams.ProcessState state = CdcrParams.ProcessState.get(zkClient.getData(CdcrProcessStateManager.this.getZnodePath(), watcher, null, true)); |
| log.info("Received new CDCR process state from watcher: {} @ {}:{}", state, collectionName, shard); |
| CdcrProcessStateManager.this.setState(state); |
| } catch (KeeperException | InterruptedException e) { |
| log.warn("Failed synchronising new state @ {}: {}", collectionName, shard, e); |
| } |
| } |
| |
| } |
| |
| } |
| |