| /* |
| * 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.ratis.conf; |
| |
| import org.apache.ratis.conf.ReconfigurationStatus.PropertyChange; |
| import org.apache.ratis.util.Daemon; |
| import org.apache.ratis.util.Timestamp; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| import java.io.IOException; |
| import java.util.Collection; |
| import java.util.HashMap; |
| import java.util.Map; |
| import java.util.Objects; |
| |
| /** |
| * Base class for implementing the {@link Reconfigurable} interface. |
| * Subclasses must override |
| * (1) {@link #getReconfigurableProperties()} to return all properties that can be reconfigurable at runtime, |
| * (2) {@link #getNewProperties()} to return the new {@link RaftProperties} to be reconfigured to, and |
| * (3) {@link #reconfigureProperty(String, String)} to change individual properties. |
| */ |
| public abstract class ReconfigurationBase implements Reconfigurable { |
| private static final Logger LOG = LoggerFactory.getLogger(ReconfigurationBase.class); |
| |
| public static Collection<PropertyChange> getChangedProperties( |
| RaftProperties newProperties, RaftProperties oldProperties) { |
| final Map<String, PropertyChange> changes = new HashMap<>(); |
| |
| // iterate over old properties |
| for (Map.Entry<String, String> oldEntry: oldProperties.entrySet()) { |
| final String prop = oldEntry.getKey(); |
| final String oldVal = oldEntry.getValue(); |
| final String newVal = newProperties.getRaw(prop); |
| |
| if (!Objects.equals(newVal, oldVal)) { |
| changes.put(prop, new PropertyChange(prop, newVal, oldVal)); |
| } |
| } |
| |
| // now iterate over new properties in order to look for properties not present in old properties |
| for (Map.Entry<String, String> newEntry: newProperties.entrySet()) { |
| final String prop = newEntry.getKey(); |
| final String newVal = newEntry.getValue(); |
| if (newVal != null && oldProperties.get(prop) == null) { |
| changes.put(prop, new PropertyChange(prop, newVal, null)); |
| } |
| } |
| |
| return changes.values(); |
| } |
| |
| class Context { |
| /** The current reconfiguration status. */ |
| private ReconfigurationStatus status = new ReconfigurationStatus(null, null, null, null); |
| /** Is this context stopped? */ |
| private boolean isStopped; |
| |
| synchronized ReconfigurationStatus getStatus() { |
| return status; |
| } |
| |
| synchronized void start() { |
| if (isStopped) { |
| throw new IllegalStateException(name + " is stopped."); |
| } |
| final Daemon previous = status.getDaemon(); |
| if (previous != null) { |
| throw new IllegalStateException(name + ": a reconfiguration task " + previous + " is already running."); |
| } |
| final Timestamp startTime = Timestamp.currentTime(); |
| final Daemon task = Daemon.newBuilder() |
| .setName("started@" + startTime) |
| .setRunnable(ReconfigurationBase.this::batchReconfiguration) |
| .build(); |
| status = new ReconfigurationStatus(startTime, null, null, task); |
| task.start(); |
| } |
| |
| synchronized void end(Map<PropertyChange, Throwable> results) { |
| status = new ReconfigurationStatus(status.getStartTime(), Timestamp.currentTime(), results, null); |
| } |
| |
| synchronized Daemon stop() { |
| isStopped = true; |
| final Daemon task = status.getDaemon(); |
| status = new ReconfigurationStatus(status.getStartTime(), null, null, null); |
| return task; |
| } |
| } |
| |
| private final String name; |
| private final RaftProperties properties; |
| private final Context context; |
| |
| /** |
| * Construct a ReconfigurableBase with the {@link RaftProperties} |
| * @param properties raft properties. |
| */ |
| protected ReconfigurationBase(String name, RaftProperties properties) { |
| this.name = name; |
| this.properties = properties; |
| this.context = new Context(); |
| } |
| |
| @Override |
| public RaftProperties getProperties() { |
| return properties; |
| } |
| |
| /** @return the new {@link RaftProperties} to be reconfigured to. */ |
| protected abstract RaftProperties getNewProperties(); |
| |
| /** |
| * Start a reconfiguration task to reload raft property in background. |
| * @throws IOException raised on errors performing I/O. |
| */ |
| public void startReconfiguration() throws IOException { |
| context.start(); |
| } |
| |
| public ReconfigurationStatus getReconfigurationStatus() { |
| return context.getStatus(); |
| } |
| |
| public void shutdown() throws InterruptedException { |
| context.stop().join(); |
| } |
| |
| /** |
| * Run a batch reconfiguration to change the current properties |
| * to the properties returned by {@link #getNewProperties()}. |
| */ |
| private void batchReconfiguration() { |
| LOG.info("{}: Starting batch reconfiguration {}", name, Thread.currentThread()); |
| final Collection<PropertyChange> changes = getChangedProperties(getNewProperties(), properties); |
| final Map<PropertyChange, Throwable> results = new HashMap<>(); |
| for (PropertyChange change : changes) { |
| LOG.info("Change property: " + change); |
| try { |
| singleReconfiguration(change.getProperty(), change.getNewValue()); |
| results.put(change, null); |
| } catch (Throwable t) { |
| results.put(change, t); |
| } |
| } |
| context.end(results); |
| } |
| |
| /** Run a single reconfiguration to change the given property to the given value. */ |
| private void singleReconfiguration(String property, String newValue) throws ReconfigurationException { |
| if (!isPropertyReconfigurable(property)) { |
| throw new ReconfigurationException("Property is not reconfigurable.", |
| property, newValue, properties.get(property)); |
| } |
| final String effective = reconfigureProperty(property, newValue); |
| LOG.info("{}: changed property {} to {} (effective {})", name, property, newValue, effective); |
| if (effective != null) { |
| properties.set(property, effective); |
| } else { |
| properties.unset(property); |
| } |
| } |
| } |