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本文主要研究一下artemis的FederatedQueue
FederatedQueue
activemq-artemis-2.11.0/artemis-server/src/main/java/org/apache/activemq/artemis/core/server/federation/queue/FederatedQueue.java
public class FederatedQueue extends FederatedAbstract implements ActiveMQServerConsumerPlugin, Serializable {
private static final Logger logger = Logger.getLogger(FederatedQueue.class);
private final Set<Matcher> includes;
private final Set<Matcher> excludes;
private final Filter metaDataFilter;
private final int priorityAdjustment;
private final FederationQueuePolicyConfiguration config;
public FederatedQueue(Federation federation, FederationQueuePolicyConfiguration config, ActiveMQServer server, FederationUpstream federationUpstream) throws ActiveMQException {
super(federation, server, federationUpstream);
Objects.requireNonNull(config.getName());
this.config = config;
this.priorityAdjustment = federationUpstream.getPriorityAdjustment() + (config.getPriorityAdjustment() == null ? -1 : config.getPriorityAdjustment());
String metaDataFilterString = config.isIncludeFederated() ? null : "hyphenated_props:" + FederatedQueueConsumer.FEDERATION_NAME + " IS NOT NULL";
metaDataFilter = FilterImpl.createFilter(metaDataFilterString);
if (config.getIncludes().isEmpty()) {
includes = Collections.emptySet();
} else {
includes = new HashSet<>(config.getIncludes().size());
for (FederationQueuePolicyConfiguration.Matcher include : config.getIncludes()) {
includes.add(new Matcher(include, wildcardConfiguration));
}
}
if (config.getExcludes().isEmpty()) {
excludes = Collections.emptySet();
} else {
excludes = new HashSet<>(config.getExcludes().size());
for (FederationQueuePolicyConfiguration.Matcher exclude : config.getExcludes()) {
excludes.add(new Matcher(exclude, wildcardConfiguration));
}
}
}
@Override
public void start() {
super.start();
server.getPostOffice()
.getAllBindings()
.values()
.stream()
.filter(b -> b instanceof QueueBinding)
.map(b -> (QueueBinding) b)
.forEach(b -> conditionalCreateRemoteConsumer(b.getQueue()));
}
/**
* After a consumer has been created
*
* @param consumer the created consumer
*/
@Override
public synchronized void afterCreateConsumer(ServerConsumer consumer) {
conditionalCreateRemoteConsumer(consumer);
}
public FederationQueuePolicyConfiguration getConfig() {
return config;
}
private void conditionalCreateRemoteConsumer(ServerConsumer consumer) {
if (server.hasBrokerFederationPlugins()) {
final AtomicBoolean conditionalCreate = new AtomicBoolean(true);
try {
server.callBrokerFederationPlugins(plugin -> {
conditionalCreate.set(conditionalCreate.get() && plugin.federatedQueueConditionalCreateConsumer(consumer));
});
} catch (ActiveMQException t) {
ActiveMQServerLogger.LOGGER.federationPluginExecutionError(t, "federatedQueueConditionalCreateConsumer");
throw new IllegalStateException(t.getMessage(), t.getCause());
}
if (!conditionalCreate.get()) {
return;
}
}
createRemoteConsumer(consumer);
}
private void conditionalCreateRemoteConsumer(Queue queue) {
queue.getConsumers()
.stream()
.filter(consumer -> consumer instanceof ServerConsumer)
.map(c -> (ServerConsumer) c).forEach(this::conditionalCreateRemoteConsumer);
}
private void createRemoteConsumer(ServerConsumer consumer) {
//We check the session meta data to see if its a federation session, if so by default we ignore these.
//To not ignore these, set include-federated to true, which will mean no meta data filter.
ServerSession serverSession = server.getSessionByID(consumer.getSessionID());
if (metaDataFilter != null && serverSession != null && metaDataFilter.match(serverSession.getMetaData())) {
return;
}
if (match(consumer)) {
FederatedConsumerKey key = getKey(consumer);
Transformer transformer = getTransformer(config.getTransformerRef());
Transformer fqqnTransformer = message -> message == null ? null : message.setAddress(key.getFqqn());
createRemoteConsumer(key, mergeTransformers(fqqnTransformer, transformer), null);
}
}
//......
}
- FederatedQueue继承了FederatedAbstract，其start方法遍历QueueBinding，然后挨个执行conditionalCreateRemoteConsumer；conditionalCreateRemoteConsumer方法通过父类的createRemoteConsumer来创建remoteQueueConsumer
FederatedAbstract
activemq-artemis-2.11.0/artemis-server/src/main/java/org/apache/activemq/artemis/core/server/federation/FederatedAbstract.java
public abstract class FederatedAbstract implements ActiveMQServerBasePlugin {
//......
public synchronized void createRemoteConsumer(FederatedConsumerKey key, Transformer transformer, ClientSessionCallback callback) {
if (started) {
FederatedQueueConsumer remoteQueueConsumer = remoteQueueConsumers.get(key);
if (remoteQueueConsumer == null) {
if (server.hasBrokerFederationPlugins()) {
try {
server.callBrokerFederationPlugins(plugin -> plugin.beforeCreateFederatedQueueConsumer(key));
} catch (ActiveMQException t) {
ActiveMQServerLogger.LOGGER.federationPluginExecutionError(t, "beforeCreateFederatedQueueConsumer");
throw new IllegalStateException(t.getMessage(), t.getCause());
}
}
remoteQueueConsumer = new FederatedQueueConsumerImpl(federation, server, transformer, key, upstream, callback);
remoteQueueConsumer.start();
remoteQueueConsumers.put(key, remoteQueueConsumer);
if (server.hasBrokerFederationPlugins()) {
try {
final FederatedQueueConsumer finalConsumer = remoteQueueConsumer;
server.callBrokerFederationPlugins(plugin -> plugin.afterCreateFederatedQueueConsumer(finalConsumer));
} catch (ActiveMQException t) {
ActiveMQServerLogger.LOGGER.federationPluginExecutionError(t, "afterCreateFederatedQueueConsumer");
throw new IllegalStateException(t.getMessage(), t.getCause());
}
}
}
remoteQueueConsumer.incrementCount();
}
}
//......
}
- FederatedAbstract的createRemoteConsumer创建FederatedQueueConsumerImpl并执行其start方法
FederatedQueueConsumerImpl
activemq-artemis-2.11.0/artemis-server/src/main/java/org/apache/activemq/artemis/core/server/federation/FederatedQueueConsumerImpl.java
public class FederatedQueueConsumerImpl implements FederatedQueueConsumer, SessionFailureListener {
private static final Logger logger = Logger.getLogger(FederatedQueueConsumerImpl.class);
private final ActiveMQServer server;
private final Federation federation;
private final FederatedConsumerKey key;
private final Transformer transformer;
private final FederationUpstream upstream;
private final AtomicInteger count = new AtomicInteger();
private final ScheduledExecutorService scheduledExecutorService;
private final int intialConnectDelayMultiplier = 2;
private final int intialConnectDelayMax = 30;
private final ClientSessionCallback clientSessionCallback;
private ClientSessionFactoryInternal clientSessionFactory;
private ClientSession clientSession;
private ClientConsumer clientConsumer;
public FederatedQueueConsumerImpl(Federation federation, ActiveMQServer server, Transformer transformer, FederatedConsumerKey key, FederationUpstream upstream, ClientSessionCallback clientSessionCallback) {
this.federation = federation;
this.server = server;
this.key = key;
this.transformer = transformer;
this.upstream = upstream;
this.scheduledExecutorService = server.getScheduledPool();
this.clientSessionCallback = clientSessionCallback;
}
@Override
public FederationUpstream getFederationUpstream() {
return upstream;
}
@Override
public Federation getFederation() {
return federation;
}
@Override
public FederatedConsumerKey getKey() {
return key;
}
@Override
public ClientSession getClientSession() {
return clientSession;
}
@Override
public int incrementCount() {
return count.incrementAndGet();
}
@Override
public int decrementCount() {
return count.decrementAndGet();
}
@Override
public void start() {
scheduleConnect(0);
}
private void scheduleConnect(int delay) {
scheduledExecutorService.schedule(() -> {
try {
connect();
} catch (Exception e) {
scheduleConnect(FederatedQueueConsumer.getNextDelay(delay, intialConnectDelayMultiplier, intialConnectDelayMax));
}
}, delay, TimeUnit.SECONDS);
}
private void connect() throws Exception {
try {
if (clientConsumer == null) {
synchronized (this) {
this.clientSessionFactory = (ClientSessionFactoryInternal) upstream.getConnection().clientSessionFactory();
this.clientSession = clientSessionFactory.createSession(upstream.getUser(), upstream.getPassword(), false, true, true, clientSessionFactory.getServerLocator().isPreAcknowledge(), clientSessionFactory.getServerLocator().getAckBatchSize());
this.clientSession.addFailureListener(this);
this.clientSession.addMetaData(FEDERATION_NAME, federation.getName().toString());
this.clientSession.addMetaData(FEDERATION_UPSTREAM_NAME, upstream.getName().toString());
this.clientSession.start();
if (clientSessionCallback != null) {
clientSessionCallback.callback(clientSession);
}
if (clientSession.queueQuery(key.getQueueName()).isExists()) {
this.clientConsumer = clientSession.createConsumer(key.getQueueName(), key.getFilterString(), key.getPriority(), false);
this.clientConsumer.setMessageHandler(this);
} else {
throw new ActiveMQNonExistentQueueException("Queue " + key.getQueueName() + " does not exist on remote");
}
}
}
} catch (Exception e) {
try {
if (clientSessionFactory != null) {
clientSessionFactory.cleanup();
}
disconnect();
} catch (ActiveMQException ignored) {
}
throw e;
}
}
@Override
public void close() {
scheduleDisconnect(0);
}
private void scheduleDisconnect(int delay) {
scheduledExecutorService.schedule(() -> {
try {
disconnect();
} catch (Exception ignored) {
}
}, delay, TimeUnit.SECONDS);
}
private void disconnect() throws ActiveMQException {
if (clientConsumer != null) {
clientConsumer.close();
}
if (clientSession != null) {
clientSession.close();
}
clientConsumer = null;
clientSession = null;
if (clientSessionFactory != null && (!upstream.getConnection().isSharedConnection() ||
clientSessionFactory.numSessions() == 0)) {
clientSessionFactory.close();
clientSessionFactory = null;
}
}
@Override
public void onMessage(ClientMessage clientMessage) {
try {
if (server.hasBrokerFederationPlugins()) {
try {
server.callBrokerFederationPlugins(plugin -> plugin.beforeFederatedQueueConsumerMessageHandled(this, clientMessage));
} catch (ActiveMQException t) {
ActiveMQServerLogger.LOGGER.federationPluginExecutionError(t, "beforeFederatedQueueConsumerMessageHandled");
throw new IllegalStateException(t.getMessage(), t.getCause());
}
}
Message message = transformer == null ? clientMessage : transformer.transform(clientMessage);
if (message != null) {
server.getPostOffice().route(message, true);
}
clientMessage.acknowledge();
if (server.hasBrokerFederationPlugins()) {
try {
server.callBrokerFederationPlugins(plugin -> plugin.afterFederatedQueueConsumerMessageHandled(this, clientMessage));
} catch (ActiveMQException t) {
ActiveMQServerLogger.LOGGER.federationPluginExecutionError(t, "afterFederatedQueueConsumerMessageHandled");
throw new IllegalStateException(t.getMessage(), t.getCause());
}
}
} catch (Exception e) {
try {
clientSession.rollback();
} catch (ActiveMQException e1) {
}
}
}
@Override
public void connectionFailed(ActiveMQException exception, boolean failedOver) {
connectionFailed(exception, failedOver, null);
}
@Override
public void connectionFailed(ActiveMQException exception, boolean failedOver, String scaleDownTargetNodeID) {
try {
clientSessionFactory.cleanup();
clientSessionFactory.close();
clientConsumer = null;
clientSession = null;
clientSessionFactory = null;
} catch (Throwable dontCare) {
}
start();
}
@Override
public void beforeReconnect(ActiveMQException exception) {
}
public interface ClientSessionCallback {
void callback(ClientSession clientSession) throws ActiveMQException;
}
}
- FederatedQueueConsumerImpl的start方法执行scheduleConnect方法，delay参数为0；scheduleConnect方法会使用scheduledExecutorService调度执行connect方法，在捕获到异常时计算新的delay再次执行scheduleConnect；其close方法执行scheduleDisconnect方法，delay参数为0；scheduleDisconnect方法则调度执行disconnect方法；connect方法通过upstream的clientSessionFactory创建clientSession并执行其start方法，之后创建clientConsumer并设置其messageHandler(
onMessage方法主要是执行server.getPostOffice().route(message, true)以及clientMessage.acknowledge())；disconnect方法则执行clientConsumer及clientSession的close
ClientSessionImpl
activemq-artemis-2.11.0/artemis-core-client/src/main/java/org/apache/activemq/artemis/core/client/impl/ClientSessionImpl.java
public final class ClientSessionImpl implements ClientSessionInternal, FailureListener {
//......
public ClientSessionImpl start() throws ActiveMQException {
checkClosed();
if (!started) {
for (ClientConsumerInternal clientConsumerInternal : cloneConsumers()) {
clientConsumerInternal.start();
}
sessionContext.sessionStart();
started = true;
}
return this;
}
//......
}
- ClientSessionImpl的start方法主要是执行clientConsumerInternal.start()及sessionContext.sessionStart()
ClientConsumerImpl
activemq-artemis-2.11.0/artemis-core-client/src/main/java/org/apache/activemq/artemis/core/client/impl/ClientConsumerImpl.java
public final class ClientConsumerImpl implements ClientConsumerInternal {
//......
public synchronized void start() {
stopped = false;
requeueExecutors();
}
private void requeueExecutors() {
for (int i = 0; i < buffer.size(); i++) {
queueExecutor();
}
}
private void queueExecutor() {
if (logger.isTraceEnabled()) {
logger.trace(this + "::Adding Runner on Executor for delivery");
}
sessionExecutor.execute(runner);
}
private class Runner implements Runnable {
@Override
public void run() {
try {
callOnMessage();
} catch (Exception e) {
ActiveMQClientLogger.LOGGER.onMessageError(e);
lastException = e;
}
}
}
private void callOnMessage() throws Exception {
if (closing || stopped) {
return;
}
session.workDone();
// We pull the message from the buffer from inside the Runnable so we can ensure priority
// ordering. If we just added a Runnable with the message to the executor immediately as we get it
// we could not do that
ClientMessageInternal message;
// Must store handler in local variable since might get set to null
// otherwise while this is executing and give NPE when calling onMessage
MessageHandler theHandler = handler;
if (theHandler != null) {
if (rateLimiter != null) {
rateLimiter.limit();
}
failedOver = false;
synchronized (this) {
message = buffer.poll();
}
if (message != null) {
if (message.containsProperty(ClientConsumerImpl.FORCED_DELIVERY_MESSAGE)) {
//Ignore, this could be a relic from a previous receiveImmediate();
return;
}
boolean expired = message.isExpired();
flowControlBeforeConsumption(message);
if (!expired) {
if (logger.isTraceEnabled()) {
logger.trace(this + "::Calling handler.onMessage");
}
final ClassLoader originalLoader = AccessController.doPrivileged(new PrivilegedAction<ClassLoader>() {
@Override
public ClassLoader run() {
ClassLoader originalLoader = Thread.currentThread().getContextClassLoader();
Thread.currentThread().setContextClassLoader(contextClassLoader);
return originalLoader;
}
});
onMessageThread = Thread.currentThread();
try {
theHandler.onMessage(message);
} finally {
try {
AccessController.doPrivileged(new PrivilegedAction<Object>() {
@Override
public Object run() {
Thread.currentThread().setContextClassLoader(originalLoader);
return null;
}
});
} catch (Exception e) {
ActiveMQClientLogger.LOGGER.failedPerformPostActionsOnMessage(e);
}
onMessageThread = null;
}
if (logger.isTraceEnabled()) {
logger.trace(this + "::Handler.onMessage done");
}
if (message.isLargeMessage()) {
message.discardBody();
}
} else {
session.expire(this, message);
}
// If slow consumer, we need to send 1 credit to make sure we get another message
if (clientWindowSize == 0) {
startSlowConsumer();
}
}
}
}
//......
}
- ClientConsumerImpl的start方法会调度执行Runner，其run方法则是执行callOnMessage方法，该方法会通过buffer.poll()拉取信息，然后执行theHandler.onMessage(message)回调
ActiveMQSessionContext
activemq-artemis-2.11.0/artemis-core-client/src/main/java/org/apache/activemq/artemis/core/protocol/core/impl/ActiveMQSessionContext.java
public class ActiveMQSessionContext extends SessionContext {
//......
public void sessionStart() throws ActiveMQException {
sessionChannel.send(new PacketImpl(PacketImpl.SESS_START));
}
//......
}
- ActiveMQSessionContext的sessionStart方法通过sessionChannel发送PacketImpl.SESS_START消息
小结
FederatedQueueConsumerImpl的start方法执行scheduleConnect方法，delay参数为0；scheduleConnect方法会使用scheduledExecutorService调度执行connect方法，在捕获到异常时计算新的delay再次执行scheduleConnect；其close方法执行scheduleDisconnect方法，delay参数为0；scheduleDisconnect方法则调度执行disconnect方法；connect方法通过upstream的clientSessionFactory创建clientSession并执行其start方法，之后创建clientConsumer并设置其messageHandler；disconnect方法则执行clientConsumer及clientSession的close
doc
来源：oschina
链接：https://my.oschina.net/go4it/blog/3166173