Examples with EventSubscriber com.cloud.framework.events.EventSubscriber used on opensource projects

Example 1 with EventSubscriber

use of com.cloud.framework.events.EventSubscriber in project cosmic by MissionCriticalCloud.

the class RabbitMQEventBus method unsubscribe.

@Override
public void unsubscribe(final UUID subscriberId, final EventSubscriber subscriber) throws EventBusException {
    try {
        final String classname = subscriber.getClass().getName();
        final String queueName = UUID.nameUUIDFromBytes(classname.getBytes()).toString();
        final Ternary<String, Channel, EventSubscriber> queueDetails = s_subscribers.get(queueName);
        final Channel channel = queueDetails.second();
        channel.basicCancel(queueName);
        s_subscribers.remove(queueName, queueDetails);
    } catch (final IOException e) {
        throw new EventBusException("Failed to unsubscribe from event bus due to " + e.getMessage(), e);
    }
}

Example 2 with EventSubscriber

use of com.cloud.framework.events.EventSubscriber in project cosmic by MissionCriticalCloud.

the class RabbitMQEventBus method subscribe.

/**
 * Call to subscribe to interested set of events
 *
 * @param topic      defines category and type of the events being subscribed to
 * @param subscriber subscriber that intends to receive event notification
 * @return UUID that represents the subscription with event bus
 * @throws EventBusException
 */
@Override
public UUID subscribe(final EventTopic topic, final EventSubscriber subscriber) throws EventBusException {
    if (subscriber == null || topic == null) {
        throw new EventBusException("Invalid EventSubscriber/EventTopic object passed.");
    }
    // create a UUID, that will be used for managing subscriptions and also used as queue name
    // for on the queue used for the subscriber on the AMQP broker
    final UUID queueId = UUID.randomUUID();
    final String queueName = queueId.toString();
    try {
        final String bindingKey = createBindingKey(topic);
        // store the subscriber details before creating channel
        s_subscribers.put(queueName, new Ternary<>(bindingKey, null, subscriber));
        // create a channel dedicated for this subscription
        final Connection connection = getConnection();
        final Channel channel = createChannel(connection);
        // create a queue and bind it to the exchange with binding key formed from event topic
        createExchange(channel, amqpExchangeName);
        channel.queueDeclare(queueName, false, false, false, null);
        channel.queueBind(queueName, amqpExchangeName, bindingKey);
        // register a callback handler to receive the events that a subscriber subscribed to
        channel.basicConsume(queueName, s_autoAck, queueName, new DefaultConsumer(channel) {

            @Override
            public void handleDelivery(final String queueName, final Envelope envelope, final AMQP.BasicProperties properties, final byte[] body) throws IOException {
                RabbitMQEventBus.this.handleDelivery(queueName, envelope, body);
            }
        });
        // update the channel details for the subscription
        final Ternary<String, Channel, EventSubscriber> queueDetails = s_subscribers.get(queueName);
        queueDetails.second(channel);
        s_subscribers.put(queueName, queueDetails);
    } catch (final AlreadyClosedException | ConnectException | NoSuchAlgorithmException | KeyManagementException | TimeoutException e) {
        s_logger.warn("Connection to AMQP service is lost. Subscription:" + queueName + " will be active after reconnection", e);
    } catch (final IOException e) {
        throw new EventBusException("Failed to subscribe to event due to " + e.getMessage(), e);
    }
    return queueId;
}

Example 3 with EventSubscriber

use of com.cloud.framework.events.EventSubscriber in project cosmic by MissionCriticalCloud.

the class RabbitMQEventBus method handleDelivery.

private void handleDelivery(final String queueName, final Envelope envelope, final byte[] body) {
    final Ternary<String, Channel, EventSubscriber> queueDetails = s_subscribers.get(queueName);
    if (queueDetails != null) {
        final EventSubscriber subscriber = queueDetails.third();
        final String routingKey = envelope.getRoutingKey();
        final String eventSource = getEventSourceFromRoutingKey(routingKey);
        final String eventCategory = getEventCategoryFromRoutingKey(routingKey);
        final String eventType = getEventTypeFromRoutingKey(routingKey);
        final String resourceType = getResourceTypeFromRoutingKey(routingKey);
        final String resourceUUID = getResourceUUIDFromRoutingKey(routingKey);
        final Event event = new Event(eventSource, eventCategory, eventType, resourceType, resourceUUID);
        event.setDescription(new String(body));
        // deliver the event to call back object provided by subscriber
        subscriber.onEvent(event);
    }
}

Example 4 with EventSubscriber

use of com.cloud.framework.events.EventSubscriber in project cosmic by MissionCriticalCloud.

the class RabbitMQEventBus method stop.

@Override
public synchronized boolean stop() {
    if (s_connection.isOpen()) {
        for (final String subscriberId : s_subscribers.keySet()) {
            final Ternary<String, Channel, EventSubscriber> subscriberDetails = s_subscribers.get(subscriberId);
            final Channel channel = subscriberDetails.second();
            try {
                channel.queueDelete(subscriberId);
                channel.abort();
            } catch (final IOException ioe) {
                s_logger.warn("Failed to delete queue: " + subscriberId + " on AMQP server due to " + ioe.getMessage());
            }
        }
    }
    closeConnection();
    return true;
}