發現問題
下面部分是io.moquette.spi.impl.BrokerInterceptor.java部分源碼
@Override
public void notifyClientConnected(final MqttConnectMessage msg) {
for (final InterceptHandler handler : this.handlers.get(InterceptConnectMessage.class)) {
LOG.debug("Sending MQTT CONNECT message to interceptor. CId={}, interceptorId={}",
msg.payload().clientIdentifier(), handler.getID());
executor.execute(() -> handler.onConnect(new InterceptConnectMessage(msg)));
}
}
@Override
public void notifyClientDisconnected(final String clientID, final String username) {
for (final InterceptHandler handler : this.handlers.get(InterceptDisconnectMessage.class)) {
LOG.debug("Notifying MQTT client disconnection to interceptor. CId={}, username={}, interceptorId={}",
clientID, username, handler.getID());
executor.execute(() -> handler.onDisconnect(new InterceptDisconnectMessage(clientID, username)));
}
}
@Override
public void notifyClientConnectionLost(final String clientID, final String username) {
for (final InterceptHandler handler : this.handlers.get(InterceptConnectionLostMessage.class)) {
LOG.debug("Notifying unexpected MQTT client disconnection to interceptor CId={}, username={}, " +
"interceptorId={}", clientID, username, handler.getID());
executor.execute(() -> handler.onConnectionLost(new InterceptConnectionLostMessage(clientID, username)));
}
}
@Override
public void notifyTopicPublished(final MqttPublishMessage msg, final String clientID, final String username) {
msg.retain();
executor.execute(() -> {
try {
int messageId = msg.variableHeader().messageId();
String topic = msg.variableHeader().topicName();
for (InterceptHandler handler : handlers.get(InterceptPublishMessage.class)) {
LOG.debug("Notifying MQTT PUBLISH message to interceptor. CId={}, messageId={}, topic={}, "
+ "interceptorId={}", clientID, messageId, topic, handler.getID());
handler.onPublish(new InterceptPublishMessage(msg, clientID, username));
}
} finally {
ReferenceCountUtil.release(msg);
}
});
}
@Override
public void notifyTopicSubscribed(final Subscription sub, final String username) {
for (final InterceptHandler handler : this.handlers.get(InterceptSubscribeMessage.class)) {
LOG.debug("Notifying MQTT SUBSCRIBE message to interceptor. CId={}, topicFilter={}, interceptorId={}",
sub.getClientId(), sub.getTopicFilter(), handler.getID());
executor.execute(() -> handler.onSubscribe(new InterceptSubscribeMessage(sub, username)));
}
}
可以發現在除了notifyTopicPublished(),其它方法中,在for循環中每次for循環,對於InterceptHandler的調用都是在線程池中每次都是新執行一個任務,但是在notifyTopicPublished()方法中是在一個線程中for循環依次調用,這樣處理首先沒有用到線程池的多線程,其次是一旦某個InterceptHandler的notifyTopicPublished方法是阻塞的,那麼後面的InterceptHandler的notifyTopicPublished()都會被阻塞。
優化邏輯
優化方向:向啓動方法一樣,每次調用InterceptHandler的notifyTopicPublished方法都是在線程池中新建一個任務
具體代碼:
public class PublishTask implements Runnable {
final MqttPublishMessage msg;
final InterceptHandler interceptHandler;
final String clientId;
final String username;
PublishTask(MqttPublishMessage msg, InterceptHandler interceptHandler, String clientId, String username) {
this.msg = msg;
this.interceptHandler = interceptHandler;
this.clientId = clientId;
this.username = username;
}
@Override
public void run() {
try {
interceptHandler.onPublish(new InterceptPublishMessage(msg, clientId, username));
} finally {
ReferenceCountUtil.release(msg);
}
}
@Override
public String toString() {
return "PublishTask{" +
"msg=" + msg +
", interceptHandler=" + interceptHandler +
", clientId='" + clientId + '\'' +
", username='" + username + '\'' +
'}';
}
public InterceptHandler getInterceptHandler() {
return interceptHandler;
}
}
@Override
public void notifyTopicPublished(final MqttPublishMessage msg, final String clientID, final String username) {
msg.retain();
try {
for (InterceptHandler handler : handlers.get(InterceptPublishMessage.class)) {
executor.execute(new PublishTask(msg.retainedDuplicate(), handler, clientID, username));
}
} finally {
ReferenceCountUtil.release(msg);
}
// executor.execute(() -> {
// try {
// int messageId = msg.variableHeader().messageId();
// String topic = msg.variableHeader().topicName();
// for (InterceptHandler handler : handlers.get(InterceptPublishMessage.class)) {
// LOG.debug("Notifying MQTT PUBLISH message to interceptor. CId={}, messageId={}, topic={}, "
// + "interceptorId={}", clientID, messageId, topic, handler.getID());
// handler.onPublish(new InterceptPublishMessage(msg, clientID, username));
// }
// } finally {
// ReferenceCountUtil.release(msg);
// }
// });
}
解釋:
(1)新建一個PublishTask用來實現調用handler.onPublish()方法。其中要注意
new PublishTask(msg.retainedDuplicate(), handler, clientID, username)中的msg.retainedDuplicate()
還要主要在兩個finally中ReferenceCountUtil.release(msg);
(2)PublishTask的toString()和getInterceptHandler()可以先不用管,會在其它地方用到,下一篇文章會講到。