/*
* 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.axis2.clustering.tribes;
import org.apache.axis2.clustering.ClusteringConstants;
import org.apache.axis2.clustering.control.wka.MemberJoinedCommand;
import org.apache.axis2.clustering.control.wka.MemberListCommand;
import org.apache.axis2.clustering.management.GroupManagementAgent;
import org.apache.axis2.context.ConfigurationContext;
import org.apache.catalina.tribes.Channel;
import org.apache.catalina.tribes.Member;
import org.apache.catalina.tribes.RemoteProcessException;
import org.apache.catalina.tribes.group.Response;
import org.apache.catalina.tribes.group.RpcChannel;
import org.apache.catalina.tribes.group.interceptors.StaticMembershipInterceptor;
import org.apache.catalina.tribes.membership.MemberImpl;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
/**
* Responsible for managing the membership. Handles membership changes.
*/
public class MembershipManager {
private static final Log log = LogFactory.getLog(MembershipManager.class);
private RpcChannel rpcMembershipChannel;
private StaticMembershipInterceptor staticMembershipInterceptor;
/**
* The domain corresponding to the membership handled by this MembershipManager
*/
private byte[] domain;
private GroupManagementAgent groupManagementAgent;
private ConfigurationContext configContext;
/**
* List of current members in the cluster. Only the members who are alive will be in this
* list
*/
private final List<Member> members = new ArrayList<Member>();
/**
* List of Well-Known members. These members may or may not be alive at a given moment.
*/
private final List<Member> wkaMembers = new ArrayList<Member>();
/**
* The member representing this node
*/
private Member localMember;
public MembershipManager(ConfigurationContext configContext) {
this.configContext = configContext;
}
public MembershipManager() {
}
public void setRpcMembershipChannel(RpcChannel rpcMembershipChannel) {
this.rpcMembershipChannel = rpcMembershipChannel;
}
public RpcChannel getRpcMembershipChannel() {
return rpcMembershipChannel;
}
public void setStaticMembershipInterceptor(
StaticMembershipInterceptor staticMembershipInterceptor) {
this.staticMembershipInterceptor = staticMembershipInterceptor;
}
public void setGroupManagementAgent(GroupManagementAgent groupManagementAgent) {
this.groupManagementAgent = groupManagementAgent;
}
public void setDomain(byte[] domain) {
this.domain = domain;
}
public byte[] getDomain() {
return domain;
}
public Member getLocalMember() {
return localMember;
}
public void setLocalMember(Member localMember) {
this.localMember = localMember;
}
public void addWellKnownMember(Member wkaMember) {
wkaMembers.add(wkaMember);
}
public void removeWellKnownMember(Member wkaMember) {
wkaMembers.remove(wkaMember);
}
/**
* A new member is added
*
* @param member The new member that joined the cluster
* @return true If the member was added to the <code>members</code> array; false, otherwise.
*/
public boolean memberAdded(Member member) {
if (log.isDebugEnabled()) {
log.debug("members.contains(member) =" + members.contains(member));
log.debug("Is in my domain: " + TribesUtil.isInDomain(member, domain));
}
// If this member already exists or if the member belongs to another domain,
// there is no need to add it
if (members.contains(member) || !TribesUtil.isInDomain(member, domain)) {
return false;
}
if (staticMembershipInterceptor != null) { // this interceptor is null when multicast based scheme is used
staticMembershipInterceptor.addStaticMember(member);
if (log.isDebugEnabled()) {
log.debug("Added static member " + TribesUtil.getName(member));
}
}
boolean shouldAddMember = localMember == null ||
TribesUtil.areInSameDomain(localMember, member);
// If this member is a load balancer, notify the respective load balance event handler?
if (groupManagementAgent != null) {
log.info("Application member " + TribesUtil.getName(member) + " joined group " +
new String(member.getDomain()));
groupManagementAgent.applicationMemberAdded(TribesUtil.toAxis2Member(member));
}
if (shouldAddMember) {
if (rpcMembershipChannel != null && isLocalMemberInitialized() &&
wkaMembers.contains(member)) { // if it is a well-known member
log.info("A WKA member " + TribesUtil.getName(member) +
" just joined the group. Sending MEMBER_LIST message.");
// send the member list to it
MemberListCommand memListCmd;
try {
memListCmd = new MemberListCommand();
List<Member> members = new ArrayList<Member>(this.members);
members.add(localMember); // Need to set the local member too
memListCmd.setMembers(members.toArray(new Member[members.size()]));
Response[] responses =
rpcMembershipChannel.send(new Member[]{member}, memListCmd,
RpcChannel.ALL_REPLY,
Channel.SEND_OPTIONS_ASYNCHRONOUS |
TribesConstants.MEMBERSHIP_MSG_OPTION, 10000);
// Once a response is received from the WKA member to the MEMBER_LIST message,
// if it does not belong to this domain, simply remove it from the members
if (responses != null && responses.length > 0 && responses[0] != null) {
Member source = responses[0].getSource();
if (!TribesUtil.areInSameDomain(source, member)) {
if (log.isDebugEnabled()) {
log.debug("WKA Member " + TribesUtil.getName(source) +
" does not belong to local domain " + new String(domain) +
". Hence removing it from the list.");
}
members.remove(member);
return false;
}
}
} catch (Exception e) {
String errMsg = "Could not send MEMBER_LIST to well-known member " +
TribesUtil.getName(member);
log.error(errMsg, e);
throw new RemoteProcessException(errMsg, e);
}
}
members.add(member);
if (log.isDebugEnabled()) {
log.debug("Added group member " + TribesUtil.getName(member) + " to domain " +
new String(member.getDomain()));
}
return true;
}
return false;
}
/**
* Send the list of members to the <code>member</code>
*
* @param member The member to whom the member list has to be sent
*/
public void sendMemberList(Member member) {
try {
MemberListCommand memListCmd = new MemberListCommand();
List<Member> members = new ArrayList<Member>(this.members);
memListCmd.setMembers(members.toArray(new Member[members.size()]));
rpcMembershipChannel.send(new Member[]{member}, memListCmd, RpcChannel.ALL_REPLY,
Channel.SEND_OPTIONS_ASYNCHRONOUS |
TribesConstants.MEMBERSHIP_MSG_OPTION, 10000);
if (log.isDebugEnabled()) {
log.debug("Sent MEMBER_LIST to " + TribesUtil.getName(member));
}
} catch (Exception e) {
String errMsg = "Could not send MEMBER_LIST to member " + TribesUtil.getName(member);
log.error(errMsg, e);
throw new RemoteProcessException(errMsg, e);
}
}
/**
* Inform all members that a particular member just joined
*
* @param member The member who just joined
*/
public void sendMemberJoinedToAll(Member member) {
try {
MemberJoinedCommand cmd = new MemberJoinedCommand();
cmd.setMember(member);
ArrayList<Member> membersToSend = (ArrayList<Member>) (((ArrayList) members).clone());
membersToSend.remove(member); // Do not send MEMBER_JOINED to the new member who just joined
if (membersToSend.size() > 0) {
rpcMembershipChannel.send(membersToSend.toArray(new Member[membersToSend.size()]), cmd,
RpcChannel.ALL_REPLY,
Channel.SEND_OPTIONS_ASYNCHRONOUS |
TribesConstants.MEMBERSHIP_MSG_OPTION,
10000);
if (log.isDebugEnabled()) {
log.debug("Sent MEMBER_JOINED[" + TribesUtil.getName(member) +
"] to all members in domain " + new String(domain));
}
}
} catch (Exception e) {
String errMsg = "Could not send MEMBER_JOINED[" + TribesUtil.getName(member) +
"] to all members ";
log.error(errMsg, e);
throw new RemoteProcessException(errMsg, e);
}
}
private boolean isLocalMemberInitialized() {
if (configContext == null) {
return false;
}
Object clusterInitialized =
configContext.getPropertyNonReplicable(ClusteringConstants.CLUSTER_INITIALIZED);
return clusterInitialized != null && clusterInitialized.equals("true");
}
/**
* A member disappeared
*
* @param member The member that left the cluster
*/
public void memberDisappeared(Member member) {
members.remove(member);
// Is this an application domain member?
if (groupManagementAgent != null) {
groupManagementAgent.applicationMemberRemoved(TribesUtil.toAxis2Member(member));
}
}
/**
* Get the list of current members
*
* @return list of current members
*/
public Member[] getMembers() {
return members.toArray(new Member[members.size()]);
}
/**
* Get the member that has been alive for the longest time
*
* @return The member that has been alive for the longest time
*/
public Member getLongestLivingMember() {
Member longestLivingMember = null;
if (members.size() > 0) {
Member member0 = members.get(0);
long longestAliveTime = member0.getMemberAliveTime();
longestLivingMember = member0;
for (Member member : members) {
if (longestAliveTime < member.getMemberAliveTime()) {
longestAliveTime = member.getMemberAliveTime();
longestLivingMember = member;
}
}
}
return longestLivingMember;
}
/**
* Get a random member from the list of current members
*
* @return A random member from the list of current members
*/
public Member getRandomMember() {
if (members.size() == 0) {
return null;
}
int memberIndex = new Random().nextInt(members.size());
return members.get(memberIndex);
}
/**
* Check whether there are any members
*
* @return true if there are other members, false otherwise
*/
public boolean hasMembers() {
return members.size() > 0;
}
/**
* Get a member
*
* @param member The member to be found
* @return The member, if it is found
*/
public Member getMember(Member member) {
if (hasMembers()) {
MemberImpl result = null;
for (int i = 0; i < this.members.size() && result == null; i++) {
if (members.get(i).equals(member)) {
result = (MemberImpl) members.get(i);
}
}
return result;
}
return null;
}
}