Java tutorial
/* * 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 brooklyn.entity.nosql.etcd; import java.util.Collection; import java.util.Map; import java.util.concurrent.atomic.AtomicInteger; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import brooklyn.entity.Entity; import brooklyn.entity.basic.Attributes; import brooklyn.entity.basic.Entities; import brooklyn.entity.basic.EntityInternal; import brooklyn.entity.basic.EntityPredicates; import brooklyn.entity.basic.Lifecycle; import brooklyn.entity.basic.ServiceStateLogic; import brooklyn.entity.basic.ServiceStateLogic.ServiceNotUpLogic; import brooklyn.entity.group.AbstractMembershipTrackingPolicy; import brooklyn.entity.group.Cluster; import brooklyn.entity.group.DynamicCluster; import brooklyn.entity.group.DynamicClusterImpl; import brooklyn.entity.trait.Startable; import brooklyn.event.basic.DependentConfiguration; import brooklyn.event.feed.ConfigToAttributes; import brooklyn.location.Location; import brooklyn.policy.PolicySpec; import brooklyn.util.task.DynamicTasks; import brooklyn.util.time.Duration; import brooklyn.util.time.Time; import com.google.common.base.Joiner; import com.google.common.base.Optional; import com.google.common.base.Preconditions; import com.google.common.base.Predicates; import com.google.common.collect.ImmutableSet; import com.google.common.collect.Iterables; import com.google.common.collect.Maps; public class EtcdClusterImpl extends DynamicClusterImpl implements EtcdCluster { private static final Logger log = LoggerFactory.getLogger(EtcdClusterImpl.class); private transient Object mutex = new Object[0]; public void init() { super.init(); setAttribute(NODE_ID, new AtomicInteger(0)); ConfigToAttributes.apply(this, ETCD_NODE_SPEC); config().set(MEMBER_SPEC, getAttribute(ETCD_NODE_SPEC)); } @Override public void start(Collection<? extends Location> locations) { ServiceStateLogic.setExpectedState(this, Lifecycle.STARTING); connectSensors(); super.start(locations); Optional<Entity> anyNode = Iterables.tryFind(getMembers(), Predicates.and(Predicates.instanceOf(EtcdNode.class), EntityPredicates.attributeEqualTo(EtcdNode.ETCD_NODE_HAS_JOINED_CLUSTER, true), EntityPredicates.attributeEqualTo(Startable.SERVICE_UP, true))); if (config().get(Cluster.INITIAL_SIZE) == 0 || anyNode.isPresent()) { setAttribute(Startable.SERVICE_UP, true); ServiceStateLogic.setExpectedState(this, Lifecycle.RUNNING); } else { log.warn("No Etcd nodes are found on the cluster: {}. Initialization Failed", getId()); ServiceStateLogic.setExpectedState(this, Lifecycle.ON_FIRE); } } protected void connectSensors() { addPolicy(PolicySpec.create(MemberTrackingPolicy.class).displayName("EtcdCluster node tracker") .configure("sensorsToTrack", ImmutableSet.of(Attributes.HOSTNAME)).configure("group", this)); } protected void onServerPoolMemberChanged(Entity member) { synchronized (mutex) { log.debug("For {}, considering membership of {} which is in locations {}", new Object[] { this, member, member.getLocations() }); Map<Entity, String> nodes = getAttribute(ETCD_CLUSTER_NODES); if (belongsInServerPool(member)) { if (nodes == null) { nodes = Maps.newLinkedHashMap(); } String name = Preconditions.checkNotNull(getNodeName(member)); // Wait until node has been installed DynamicTasks .queueIfPossible( DependentConfiguration.attributeWhenReady(member, EtcdNode.ETCD_NODE_INSTALLED)) .orSubmitAndBlock(this).andWaitForSuccess(); // Check for first node in the cluster. Entity firstNode = getAttribute(DynamicCluster.FIRST); if (member.equals(firstNode)) { nodes.put(member, name); recalculateClusterAddresses(nodes); log.info("Adding first node {}: {}; {} to cluster", new Object[] { this, member, name }); ((EntityInternal) member).setAttribute(EtcdNode.ETCD_NODE_HAS_JOINED_CLUSTER, Boolean.TRUE); } else { int retry = 3; // TODO use a configurable Repeater instead? while (retry-- > 0 && member.getAttribute(EtcdNode.ETCD_NODE_HAS_JOINED_CLUSTER) == null && !nodes.containsKey(member)) { Optional<Entity> anyNodeInCluster = Iterables.tryFind(nodes.keySet(), Predicates.and(Predicates.instanceOf(EtcdNode.class), EntityPredicates .attributeEqualTo(EtcdNode.ETCD_NODE_HAS_JOINED_CLUSTER, Boolean.TRUE))); if (anyNodeInCluster.isPresent()) { DynamicTasks .queueIfPossible(DependentConfiguration .attributeWhenReady(anyNodeInCluster.get(), Startable.SERVICE_UP)) .orSubmitAndBlock(this).andWaitForSuccess(); Entities.invokeEffectorWithArgs(this, anyNodeInCluster.get(), EtcdNode.JOIN_ETCD_CLUSTER, name, getNodeAddress(member)).blockUntilEnded(); nodes.put(member, name); recalculateClusterAddresses(nodes); log.info("Adding node {}: {}; {} to cluster", new Object[] { this, member, name }); ((EntityInternal) member).setAttribute(EtcdNode.ETCD_NODE_HAS_JOINED_CLUSTER, Boolean.TRUE); } else { log.info("Waiting for first node in cluster {}", this); Time.sleep(Duration.seconds(15)); } } } } else { if (nodes != null && nodes.containsKey(member)) { Optional<Entity> anyNodeInCluster = Iterables.tryFind(nodes.keySet(), Predicates.and( Predicates.instanceOf(EtcdNode.class), EntityPredicates .attributeEqualTo(EtcdNode.ETCD_NODE_HAS_JOINED_CLUSTER, Boolean.TRUE), Predicates.not(Predicates.equalTo(member)))); if (anyNodeInCluster.isPresent()) { Entities.invokeEffectorWithArgs(this, anyNodeInCluster.get(), EtcdNode.LEAVE_ETCD_CLUSTER, getNodeName(member)).blockUntilEnded(); } nodes.remove(member); recalculateClusterAddresses(nodes); log.info("Removing node {}: {}; {} from cluster", new Object[] { this, member, getNodeName(member) }); ((EntityInternal) member).setAttribute(EtcdNode.ETCD_NODE_HAS_JOINED_CLUSTER, Boolean.FALSE); } } ServiceNotUpLogic.updateNotUpIndicatorRequiringNonEmptyMap(this, ETCD_CLUSTER_NODES); log.debug("Done {} checkEntity {}", this, member); } } private void recalculateClusterAddresses(Map<Entity, String> nodes) { Map<String, String> addresses = Maps.newHashMap(); for (Entity entity : nodes.keySet()) { if (entity instanceof EtcdNode) { addresses.put(getNodeName(entity), getNodeAddress(entity)); } } setAttribute(ETCD_CLUSTER_NODES, nodes); setAttribute(NODE_LIST, Joiner.on(",").withKeyValueSeparator("=").join(addresses)); } protected boolean belongsInServerPool(Entity member) { if (member.getAttribute(Attributes.HOSTNAME) == null) { log.debug("Members of {}, checking {}, eliminating because hostname not yet set", this, member); return false; } if (!getMembers().contains(member)) { log.debug("Members of {}, checking {}, eliminating because not member", this, member); return false; } log.debug("Members of {}, checking {}, approving", this, member); return true; } private String getNodeName(Entity node) { return node.getAttribute(EtcdNode.ETCD_NODE_NAME); } private String getNodeAddress(Entity node) { return "http://" + node.getAttribute(Attributes.SUBNET_HOSTNAME) + ":" + node.getAttribute(EtcdNode.ETCD_PEER_PORT); } public static class MemberTrackingPolicy extends AbstractMembershipTrackingPolicy { @Override protected void onEntityEvent(EventType type, Entity target) { ((EtcdClusterImpl) entity).onServerPoolMemberChanged(target); } } }