| /* |
| * 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.sling.discovery.impl.cluster.voting; |
| |
| import java.util.Calendar; |
| import java.util.Date; |
| import java.util.HashMap; |
| import java.util.Iterator; |
| import java.util.Map; |
| import java.util.Set; |
| |
| import javax.jcr.Property; |
| import javax.jcr.RepositoryException; |
| import javax.jcr.ValueFormatException; |
| |
| import org.apache.sling.api.resource.ModifiableValueMap; |
| import org.apache.sling.api.resource.PersistenceException; |
| import org.apache.sling.api.resource.Resource; |
| import org.apache.sling.api.resource.ResourceResolver; |
| import org.apache.sling.api.resource.ValueMap; |
| import org.apache.sling.discovery.commons.providers.util.ResourceHelper; |
| import org.apache.sling.discovery.impl.Config; |
| import org.apache.sling.discovery.impl.common.View; |
| import org.apache.sling.discovery.impl.common.ViewHelper; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| /** |
| * DAO for an ongoing voting, providing a few helper methods |
| */ |
| public class VotingView extends View { |
| |
| /** |
| * use static logger to avoid frequent initialization as is potentially the |
| * case with ClusterViewResource. |
| **/ |
| private final static Logger logger = LoggerFactory |
| .getLogger(VotingView.class); |
| |
| /** |
| * Create a new voting with the given list of instances, the given |
| * voting/view id and the given slingid of the initiator. |
| * @param newViewId the new voting/view id |
| * @param initiatorId the slingid of the initiator |
| * @param liveInstances the list of live instances to add to the voting |
| * @return a DAO object representing the voting |
| */ |
| public static VotingView newVoting(final ResourceResolver resourceResolver, |
| final Config config, |
| final String newViewId, String initiatorId, final Set<String> liveInstances) throws PersistenceException { |
| if (!liveInstances.contains(initiatorId)) { |
| // SLING-4617 : a voting, on a single instance, was created without the local instance |
| // this should in no case happen - the local instance should always be part of the live |
| // instances. if that's not the case, then something's fishy and we should not create |
| // the new voting - and instead rely on a retry later. |
| logger.warn("newVoting: liveInstances does not include initiatorId (local instance) - not creating new, invalid, voting"); |
| return null; |
| } |
| final Resource votingResource = ResourceHelper.getOrCreateResource( |
| resourceResolver, config.getOngoingVotingsPath() + "/" |
| + newViewId); |
| final ModifiableValueMap votingMap = votingResource.adaptTo(ModifiableValueMap.class); |
| votingMap.put("votingStart", Calendar.getInstance()); |
| |
| String clusterId = null; |
| Calendar clusterIdDefinedAt = null; |
| String clusterIdDefinedBy = null; |
| final View currentlyEstablishedView = ViewHelper.getEstablishedView(resourceResolver, config); |
| if (currentlyEstablishedView != null) { |
| final ValueMap establishedViewValueMap = currentlyEstablishedView.getResource().adaptTo(ValueMap.class); |
| clusterId = establishedViewValueMap.get(VIEW_PROPERTY_CLUSTER_ID, String.class); |
| if (clusterId == null || clusterId.length() == 0) { |
| clusterId = currentlyEstablishedView.getResource().getName(); |
| } |
| Date date = establishedViewValueMap.get(VIEW_PROPERTY_CLUSTER_ID_DEFINED_AT, Date.class); |
| if (date!=null) { |
| clusterIdDefinedAt = Calendar.getInstance(); |
| clusterIdDefinedAt.setTime(date); |
| } |
| clusterIdDefinedBy = establishedViewValueMap.get(VIEW_PROPERTY_CLUSTER_ID_DEFINED_BY, String.class); |
| } |
| if (clusterId == null || clusterId.length() == 0) { |
| clusterId = newViewId; |
| clusterIdDefinedAt = Calendar.getInstance(); |
| } |
| votingMap.put(VIEW_PROPERTY_CLUSTER_ID, clusterId); |
| if (clusterIdDefinedAt != null) { |
| votingMap.put(VIEW_PROPERTY_CLUSTER_ID_DEFINED_AT, clusterIdDefinedAt); |
| } |
| if (clusterIdDefinedBy == null || clusterIdDefinedBy.length() == 0) { |
| clusterIdDefinedBy = initiatorId; |
| } |
| votingMap.put(VIEW_PROPERTY_CLUSTER_ID_DEFINED_BY, clusterIdDefinedBy); |
| |
| final Resource membersResource = resourceResolver.create(votingResource, "members", null); |
| final Iterator<String> it = liveInstances.iterator(); |
| while (it.hasNext()) { |
| String memberId = it.next(); |
| Map<String, Object> properties = new HashMap<String, Object>(); |
| if (memberId.equals(initiatorId)) { |
| properties.put("initiator", true); |
| properties.put("vote", true); |
| properties.put("votedAt", Calendar.getInstance()); |
| } |
| Resource instanceResource = ResourceHelper.getOrCreateResource( |
| resourceResolver, config.getClusterInstancesPath() + "/" |
| + memberId); |
| String leaderElectionId = instanceResource.adaptTo(ValueMap.class) |
| .get("leaderElectionId", String.class); |
| properties.put("leaderElectionId", leaderElectionId); |
| |
| resourceResolver.create(membersResource, memberId, properties); |
| } |
| logger.debug("newVoting: committing new voting: newViewId="+newViewId+", initiatorId="+initiatorId+", resource="+votingResource+", #members: "+liveInstances.size()+", members: "+liveInstances); |
| resourceResolver.commit(); |
| logger.info("newVoting: new voting started: newViewId="+newViewId+", initiatorId="+initiatorId+", resource="+votingResource+", #members: "+liveInstances.size()+", members: "+liveInstances); |
| return new VotingView(votingResource); |
| } |
| |
| /** |
| * Construct a voting view based on the given resource |
| * @param viewResource the resource which is the place the voting is kept |
| */ |
| public VotingView(final Resource viewResource) { |
| super(viewResource); |
| } |
| |
| public String getVotingId() { |
| return getResource().getName(); |
| } |
| |
| @Override |
| public String toString() { |
| try { |
| final Resource members = getResource().getChild("members"); |
| String initiatorId = null; |
| final StringBuilder sb = new StringBuilder(); |
| if (members != null) { |
| Iterator<Resource> it = members.getChildren().iterator(); |
| while (it.hasNext()) { |
| Resource r = it.next(); |
| if (sb.length() != 0) { |
| sb.append(", "); |
| } |
| sb.append(r.getName()); |
| ValueMap properties = r.adaptTo(ValueMap.class); |
| if (properties != null) { |
| Boolean initiator = properties.get("initiator", |
| Boolean.class); |
| if (initiator != null && initiator) { |
| initiatorId = r.getName(); |
| } |
| } |
| } |
| } |
| return "a VotingView[viewId=" + getViewId() |
| + ", id=" + getResource().getName() + ", initiator=" |
| + initiatorId + ", members=" + sb + "]"; |
| } catch(Exception e) { |
| return "a VotingView["+super.toString()+"]"; |
| } |
| } |
| |
| /** |
| * Checks whether this voting is still ongoing - that is, whether |
| * a valid votingStart is set and whether that's within the heartbeat timeout configured |
| * @param config |
| * @return |
| */ |
| public boolean isOngoingVoting(final Config config) { |
| final long votingStart = getVotingStartTime(); |
| if (votingStart==-1) { |
| return false; |
| } |
| final long now = System.currentTimeMillis(); |
| final long diff = now - votingStart; |
| return diff < config.getHeartbeatTimeoutMillis(); |
| } |
| |
| /** |
| * Checks whether this voting has timed out - that is, whether |
| * there is a valid votingStart set and whether that has timed out |
| */ |
| public boolean isTimedoutVoting(final Config config) { |
| final long votingStart = getVotingStartTime(); |
| if (votingStart==-1) { |
| return false; |
| } |
| final long now = System.currentTimeMillis(); |
| final long diff = now - votingStart; |
| return diff > config.getHeartbeatTimeoutMillis(); |
| } |
| |
| /** Get the value of the votingStart property - or -1 if anything goes wrong reading that **/ |
| private long getVotingStartTime() { |
| ValueMap properties = null; |
| try{ |
| properties = getResource().adaptTo(ValueMap.class); |
| } catch(RuntimeException e) { |
| logger.info("getVotingStartTime: could not get properties of "+getResource()+". Likely in creation: "+e, e); |
| return -1; |
| } |
| if (properties == null) { |
| // no properties, odd. then it's not a valid voting. |
| return -1; |
| } |
| final Date votingStartDate = properties.get("votingStart", Date.class); |
| if (votingStartDate == null) { |
| if (logger.isDebugEnabled()) { |
| logger.debug("getVotingStartTime: got a voting without votingStart. Likely in creation: " |
| + getResource()); |
| } |
| return -1; |
| } |
| final long votingStart = votingStartDate.getTime(); |
| return votingStart; |
| } |
| |
| /** |
| * Checks whether there are any no votes on this voting |
| * @return true if there are any no votes on this voting |
| */ |
| public boolean hasNoVotes() { |
| Resource m = getResource().getChild("members"); |
| if (m==null) { |
| // the vote is being created. wait. |
| return false; |
| } |
| final Iterator<Resource> it = m.getChildren() |
| .iterator(); |
| while (it.hasNext()) { |
| Resource aMemberRes = it.next(); |
| ValueMap properties = aMemberRes.adaptTo(ValueMap.class); |
| if (properties == null) { |
| continue; |
| } |
| Boolean vote = properties.get("vote", Boolean.class); |
| if (vote != null && !vote) { |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| /** |
| * Checks whether the given slingId has voted yes for this voting |
| * @param slingId the sling id to check for |
| * @return true if the given slingId has voted yes for this voting |
| */ |
| public boolean hasVotedYes(final String slingId) { |
| final Boolean vote = getVote(slingId); |
| return vote != null && vote; |
| } |
| |
| /** |
| * Get the vote of the instance with the given slingId |
| * @param slingId |
| * @return null if that instance did not vote yet (or the structure |
| * is faulty), true if the instance voted yes, false if it voted no |
| */ |
| public Boolean getVote(String slingId) { |
| Resource members = getResource().getChild("members"); |
| if (members==null) { |
| return null; |
| } |
| final Resource memberResource = members.getChild( |
| slingId); |
| if (memberResource == null) { |
| return null; |
| } |
| final ValueMap properties = memberResource.adaptTo(ValueMap.class); |
| if (properties == null) { |
| return null; |
| } |
| final Boolean vote = properties.get("vote", Boolean.class); |
| return vote; |
| } |
| |
| /** |
| * Checks whether this voting was initiated by the given slingId |
| * @return whether this voting was initiated by the given slingId |
| */ |
| public boolean isInitiatedBy(final String slingId) { |
| Resource r = getResource(); |
| if (r == null) { |
| return false; |
| } |
| Resource members = r.getChild("members"); |
| if (members == null) { |
| if (logger.isDebugEnabled()) { |
| logger.debug("isInitiatedBy: slingId=" + slingId + ", members null!"); |
| } |
| return false; |
| } |
| final Resource memberResource = members.getChild( |
| slingId); |
| if (memberResource == null) { |
| if (logger.isDebugEnabled()) { |
| logger.debug("isInitiatedBy: slingId=" + slingId + ", memberResource null!"); |
| } |
| return false; |
| } |
| final ValueMap properties = memberResource.adaptTo(ValueMap.class); |
| if (properties == null) { |
| if (logger.isDebugEnabled()) { |
| logger.debug("isInitiatedBy: slingId=" + slingId + ", properties null!"); |
| } |
| return false; |
| } |
| final Boolean initiator = properties.get("initiator", Boolean.class); |
| boolean result = initiator != null && initiator; |
| if (logger.isDebugEnabled()) { |
| logger.debug("isInitiatedBy: slingId=" + slingId + ", initiator=" + initiator + ", result=" + result); |
| } |
| return result; |
| } |
| |
| /** |
| * add a vote from the given slingId to this voting |
| * @param slingId the slingId which is voting |
| * @param vote true for a yes-vote, false for a no-vote |
| */ |
| public void vote(final String slingId, final Boolean vote, |
| final String leaderElectionId) { |
| if (logger.isDebugEnabled()) { |
| logger.debug("vote: slingId=" + slingId + ", vote=" + vote); |
| } |
| Resource r = getResource(); |
| if (r == null) { |
| logger.error("vote: no resource set. slingId = " + slingId + ", vote=" + vote); |
| return; |
| } |
| Resource members = r.getChild("members"); |
| if (members == null) { |
| logger.error("vote: no members resource available for " + r + ". slingId = " + slingId + ", vote=" + vote); |
| return; |
| } |
| final Resource memberResource = members.getChild( |
| slingId); |
| if (memberResource == null) { |
| if (vote == null || !vote) { |
| // if I wanted to vote no or empty, then it's no big deal |
| // that I can't find my entry .. |
| logger.debug("vote: no memberResource found for slingId=" + slingId |
| + ", vote=" + vote + ", resource=" + getResource()); |
| } else { |
| // if I wanted to vote yes, then it is a big deal that I can't find myself |
| logger.error("vote: no memberResource found for slingId=" + slingId |
| + ", vote=" + vote + ", resource=" + getResource()); |
| } |
| return; |
| } |
| final ModifiableValueMap memberMap = memberResource.adaptTo(ModifiableValueMap.class); |
| |
| if (vote == null) { |
| if (memberMap.containsKey("vote")) { |
| logger.info("vote: removing vote (vote==null) of slingId="+slingId+" on: "+this); |
| } else { |
| logger.debug("vote: removing vote (vote==null) of slingId="+slingId+" on: "+this); |
| } |
| memberMap.remove("vote"); |
| } else { |
| boolean shouldVote = true; |
| try { |
| if (memberMap.containsKey("vote")) { |
| Object v = memberMap.get("vote"); |
| if (v instanceof Property) { |
| Property p = (Property)v; |
| if (p.getBoolean() == vote) { |
| logger.debug("vote: already voted, with same vote ("+vote+"), not voting again"); |
| shouldVote = false; |
| } |
| } else if (v instanceof Boolean) { |
| Boolean b = (Boolean)v; |
| if (b.equals(vote)) { |
| logger.debug("vote: already voted, with same vote ("+vote+"), not voting again"); |
| shouldVote = false; |
| } |
| } |
| } |
| } catch (ValueFormatException e) { |
| logger.warn("vote: got a ValueFormatException: "+e, e); |
| } catch (RepositoryException e) { |
| logger.warn("vote: got a RepositoryException: "+e, e); |
| } |
| if (shouldVote) { |
| logger.info("vote: slingId=" + slingId + " is voting vote=" + vote+" on "+getResource()); |
| memberMap.put("vote", vote); |
| memberMap.put("votedAt", Calendar.getInstance()); |
| String currentLeaderElectionId = memberMap.get("leaderElectionId", String.class); |
| if (leaderElectionId!=null && |
| (currentLeaderElectionId == null || !currentLeaderElectionId.equals(leaderElectionId))) { |
| // SLING-5030 : to ensure leader-step-down after being |
| // isolated from the cluster, the leaderElectionId must |
| // be explicitly set upon voting. |
| // for 99% of the cases not be necessary, |
| // for the rejoin-after-isolation case however it is |
| logger.info("vote: changing leaderElectionId on vote to "+leaderElectionId); |
| memberMap.put("leaderElectionId", leaderElectionId); |
| memberMap.put("leaderElectionIdCreatedAt", new Date()); |
| } |
| } |
| } |
| try { |
| getResource().getResourceResolver().commit(); |
| } catch (PersistenceException e) { |
| logger.error("vote: PersistenceException while voting: "+e, e); |
| } |
| } |
| |
| /** |
| * Checks whether this voting is winning - winning is when it has |
| * votes from each of the members and all are yes votes |
| * @return true if this voting is winning |
| */ |
| public boolean isWinning() { |
| final Resource members = getResource().getChild("members"); |
| if (members==null) { |
| // the vote is being created. wait. |
| return false; |
| } |
| try{ |
| final Iterable<Resource> children = members.getChildren(); |
| final Iterator<Resource> it = children.iterator(); |
| boolean isWinning = false; |
| while (it.hasNext()) { |
| Resource aMemberRes = it.next(); |
| try{ |
| ValueMap properties = aMemberRes.adaptTo(ValueMap.class); |
| Boolean vote = properties.get("vote", Boolean.class); |
| if (vote != null && vote) { |
| isWinning = true; |
| continue; |
| } |
| return false; |
| } catch(RuntimeException re) { |
| logger.info("isWinning: Could not check vote due to "+re); |
| return false; |
| } |
| } |
| return isWinning; |
| } catch(RuntimeException re) { |
| // SLING-2945: gracefully handle case where members node is |
| // deleted by another instance |
| logger.info("isWinning: could not check vote due to "+re); |
| return false; |
| } |
| } |
| |
| /** |
| * Checks if this voting matches the current live view |
| * @throws Exception when something failed during matching |
| */ |
| public String matchesLiveView(final Config config) throws Exception { |
| Resource clusterNodesRes = getResource().getResourceResolver() |
| .getResource(config.getClusterInstancesPath()); |
| if (clusterNodesRes == null) { |
| throw new Exception("no clusterNodesRes["+getResource()+"]"); |
| } |
| return matchesLiveView(clusterNodesRes, config); |
| } |
| |
| } |
