When I use RabbitMQ as Flink DataStream Source,just as the Flink Documentation said.
final StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
// checkpointing is required for exactly-once or at-least-once guarantees
env.enableCheckpointing(...);
final RMQConnectionConfig connectionConfig = new RMQConnectionConfig.Builder()
.setHost("localhost")
.setPort(5000)
...
.build();
final DataStream<String> stream = env
.addSource(new RMQSource<String>(
connectionConfig, // config for the RabbitMQ connection
"queueName", // name of the RabbitMQ queue to consume
true, // use correlation ids; can be false if only at-least-once is required
new SimpleStringSchema())) // deserialization schema to turn messages into Java objects
.setParallelism(1); // non-parallel source is only required for exactly-once
This code will connect to RabbitMQ and auto create Queue "queueName".So I have got a problem. The RabbitMQ Queue already exist,I created it before. I don't want Flink try to create again. And the problem is Flink create the Queue without some paramters, that is conflict with the Queue I created before. Here is the Exception:
Caused by: com.rabbitmq.client.ShutdownSignalException: channel error; protocol method: #method<channel.close>(reply-code=406, reply-text=PRECONDITION_FAILED - inequivalent arg 'x-message-ttl' for queue 'queueName' in vhost '/': received none but current is the value '604800000' of type 'long', class-id=50, method-id=10)
at com.rabbitmq.utility.ValueOrException.getValue(ValueOrException.java:66)
at com.rabbitmq.utility.BlockingValueOrException.uninterruptibleGetValue(BlockingValueOrException.java:36)
at com.rabbitmq.client.impl.AMQChannel$BlockingRpcContinuation.getReply(AMQChannel.java:443)
at com.rabbitmq.client.impl.AMQChannel.privateRpc(AMQChannel.java:263)
at com.rabbitmq.client.impl.AMQChannel.exnWrappingRpc(AMQChannel.java:136)
... 10 more
How to make Flink just subscribe a RabbitMQ queue without try to create a new one? Thank you all.
You can write your own class extending RMQSource and override setupQueue method in order to not create queue
Related
there:
I got the error when use ignite cache.
My system select a master node use zookeeper,and has many slave nodes.The master process ignite cache expired values and put in an ignite queue.The slave node provide data into ignite cache use streamer.addData(k,v) and consume the ignite queue.
My code is:
ignite cache and streamer :
// use zookeeper IpFinder
ignite = Ignition.getOrStart(igniteConfiguration);
igniteCache = ignite.getOrCreateCache(cacheConfiguration);
igniteCache.registerCacheEntryListener(new MutableCacheEntryListenerConfiguration<>(
(Factory<CacheEntryListener<K, CountValue>>)() -> (CacheEntryExpiredListener<K, CountValue>)this
::onCacheExpired, null, true, true));
//onCacheExpired master resolve the expired entry and put in igniteQueue
cacheConfiguration.setExpiryPolicyFactory(CreatedExpiryPolicy.factoryOf(Duration.ONE_MINUTE));
igniteDataStreamer = ignite.dataStreamer(igniteCache.getName());
igniteDataStreamer.deployClass(BaseIgniteStreamCount.class);
igniteDataStreamer.allowOverwrite(true);
igniteDataStreamer.receiver(StreamTransformer.from((CacheEntryProcessor<K, CountValue, Object>)(e, arg) -> {
// process the value.
return null;
}));
master process the entry expired from the cache,and put in ignite queue:
CollectionConfiguration collectionConfiguration = new CollectionConfiguration().setCollocated(true);
queue = ignite.queue(igniteQueueName, 0, collectionConfiguration);
the slaves consume the queue.
but i got error log below after running hours later:
2017-09-14 17:06:45,256 org.apache.ignite.logger.java.JavaLogger warning
WARNING: >>> Possible starvation in striped pool.
Thread name: sys-stripe-6-#7%ignite%
Queue: []
Deadlock: false
Completed: 77168
Thread [name="sys-stripe-6-#7%ignite%", id=134, state=WAITING, blockCnt=0, waitCnt=68842]
at sun.misc.Unsafe.park(Native Method)
at java.util.concurrent.locks.LockSupport.park(LockSupport.java:304)
at o.a.i.i.util.future.GridFutureAdapter.get0(GridFutureAdapter.java:176)
at o.a.i.i.util.future.GridFutureAdapter.get(GridFutureAdapter.java:139)
at o.a.i.i.processors.continuous.GridContinuousProcessor.addNotification(GridContinuousProcessor.java:935)
at o.a.i.i.processors.cache.query.continuous.CacheContinuousQueryHandler.onEntryUpdate(CacheContinuousQueryHandler.java:850)
at o.a.i.i.processors.cache.query.continuous.CacheContinuousQueryHandler.access$700(CacheContinuousQueryHandler.java:82)
at o.a.i.i.processors.cache.query.continuous.CacheContinuousQueryHandler$1.onEntryUpdated(CacheContinuousQueryHandler.java:413)
at o.a.i.i.processors.cache.query.continuous.CacheContinuousQueryManager.onEntryExpired(CacheContinuousQueryManager.java:429)
at o.a.i.i.processors.cache.GridCacheMapEntry.onExpired(GridCacheMapEntry.java:3046)
at o.a.i.i.processors.cache.GridCacheMapEntry.onTtlExpired(GridCacheMapEntry.java:2961)
at o.a.i.i.processors.cache.GridCacheTtlManager$1.applyx(GridCacheTtlManager.java:61)
at o.a.i.i.processors.cache.GridCacheTtlManager$1.applyx(GridCacheTtlManager.java:52)
at o.a.i.i.util.lang.IgniteInClosure2X.apply(IgniteInClosure2X.java:38)
at o.a.i.i.processors.cache.IgniteCacheOffheapManagerImpl.expire(IgniteCacheOffheapManagerImpl.java:1007)
at o.a.i.i.processors.cache.GridCacheTtlManager.expire(GridCacheTtlManager.java:198)
at o.a.i.i.processors.cache.GridCacheTtlManager.expire(GridCacheTtlManager.java:160)
at o.a.i.i.processors.cache.GridCacheUtils.unwindEvicts(GridCacheUtils.java:854)
at o.a.i.i.processors.cache.GridCacheIoManager.processMessage(GridCacheIoManager.java:1073)
at o.a.i.i.processors.cache.GridCacheIoManager.onMessage0(GridCacheIoManager.java:561)
at o.a.i.i.processors.cache.GridCacheIoManager.handleMessage(GridCacheIoManager.java:378)
at o.a.i.i.processors.cache.GridCacheIoManager.handleMessage(GridCacheIoManager.java:304)
at o.a.i.i.processors.cache.GridCacheIoManager.access$100(GridCacheIoManager.java:99)
at o.a.i.i.processors.cache.GridCacheIoManager$1.onMessage(GridCacheIoManager.java:293)
at o.a.i.i.managers.communication.GridIoManager.invokeListener(GridIoManager.java:1556)
at o.a.i.i.managers.communication.GridIoManager.processRegularMessage0(GridIoManager.java:1184)
at o.a.i.i.managers.communication.GridIoManager.access$4200(GridIoManager.java:126)
at o.a.i.i.managers.communication.GridIoManager$9.run(GridIoManager.java:1097)
at o.a.i.i.util.StripedExecutor$Stripe.run(StripedExecutor.java:483)
at java.lang.Thread.run(Thread.java:745)
Striped pool is responsible for messages processing. This warning tells you that there is no progress happening on some of the stripes. It may happen due to a bad network connection or when you put massive objects to a cache or a queue.
You may find more information about it in these threads:
http://apache-ignite-users.70518.x6.nabble.com/Possible-starvation-in-striped-pool-td14892.html
http://apache-ignite-users.70518.x6.nabble.com/Possible-starvation-in-striped-pool-message-td15993.html
Can we enable delayed retries with nservicebus and MSMQ transport.
When i do it it will throw a warning and move the message to error queue.
"Recoverability policy requested DelayedRetry however delayed delivery capability is not available with the current endpoint configuration. Moving message to error queue instead."
But according to nservicebus documentation it tells delayed retry can be performed if delayed delivery is supported. And i have below about delayed delivery.
"NServiceBus provides delayed deliver feature for transports that don't have native support for delayed message delivery, i.e. for MSMQ and SQL Server transports. "
endpointConfiguration.SendFailedMessagesTo("error");
endpointConfiguration.AuditProcessedMessagesTo("audit");
endpointConfiguration.DisableFeature<TimeoutManager>();
var messageProcessingConcurrency = ConfigurationManager.AppSettings["NservicebusMessageProcessingConcurrency"];
endpointConfiguration.LimitMessageProcessingConcurrencyTo(int.Parse(messageProcessingConcurrency));
//configuring delayed retries
var recoverability = endpointConfiguration.Recoverability();
//recoverability.CustomPolicy(OrderRecoverability.CustomRetryPolicy);
recoverability.Delayed(
delayed =>
{
delayed.NumberOfRetries(2);
delayed.TimeIncrease(TimeSpan.FromMinutes(30));
});
//no imediate retries
recoverability.Immediate(
immediate =>
{
immediate.NumberOfRetries(0);
});
endpointConfiguration.UsePersistence<MsmqPersistence>();
var transport = endpointConfiguration.UseTransport<MsmqTransport>();
transport.Transactions(TransportTransactionMode.SendsAtomicWithReceive);
var conventions = endpointConfiguration.Conventions();
conventions
.DefiningEventsAs(
t =>
t.Namespace != null
&& t.Namespace.StartsWith("Dodo.Fibre.Provisioning.Messages"));
As requested i have commented out the timeout manager disable line as below.
// endpointConfiguration.DisableFeature();
But i can not start endpoint as i am getting below error.
2017-08-01 08:45:28.074 FATAL NServiceBus.Hosting.Windows.WindowsHost Start fail
ure
System.Exception: The selected persistence doesn't have support for timeout stor
age. Select another persistence or disable the timeout manager feature using end
pointConfiguration.DisableFeature<TimeoutManager>()
at NServiceBus.Features.TimeoutManager.Setup(FeatureConfigurationContext cont
ext) in C:\BuildAgent\work\3206e2123f54fce4\src\NServiceBus.Core\DelayedDelivery
\TimeoutManager\TimeoutManager.cs:line 34
at NServiceBus.Features.FeatureActivator.ActivateFeature(FeatureInfo featureI
nfo, List`1 featuresToActivate, IConfigureComponents container, PipelineSettings
pipelineSettings, RoutingComponent routing) in C:\BuildAgent\work\3206e2123f54f
ce4\src\NServiceBus.Core\Features\FeatureActivator.cs:line 194
at NServiceBus.Features.FeatureActivator.SetupFeatures(IConfigureComponents c
ontainer, PipelineSettings pipelineSettings, RoutingComponent routing) in C:\Bui
ldAgent\work\3206e2123f54fce4\src\NServiceBus.Core\Features\FeatureActivator.cs:
line 57
at NServiceBus.InitializableEndpoint.<Initialize>d__1.MoveNext() in C:\BuildA
gent\work\3206e2123f54fce4\src\NServiceBus.Core\InitializableEndpoint.cs:line 60
From your configuration code I can see that you have disabled TimeoutManager and that's the reason the delayed retries are not working as expected e.g.
endpointConfiguration.DisableFeature<TimeoutManager>();
Any reason for that? While some transport like Azure ServiceBus / RabbitMQ have built-in delayed-delivery, MSMQ does not have that and that work is managed by the timeout manager.
I have got 10 queues on activemq server.
I have producer which want to push messages on one of the queue (the producer will select the queue randomly run time to put message on queue), how can I pass destination name in createProducer method.
I understand that I need to pass an object of type Destination. the producer would know the queues name on the server. Is it possible to pass (or convert) a string to Destination object type and pass that to createproducer method.
Thanks
If I understand your problem correctly;
If you're running Java and have a valid session, you could use Session.createQueue();
// Create a Destination using the queue name
Destination destination = session.createQueue("queue name");
// Create a MessageProducer from the Session to the Queue
MessageProducer producer = session.createProducer(destination);
Here is a complete example of doing this at the Apache site.
I'm trying to build RPC service at PHP using RabbitMQ similar to this example: http://www.rabbitmq.com/tutorials/tutorial-six-java.html
I'm using this PECL extension: http://pecl.php.net/package/amqp (version 1.0.3)
The problem is that my Callback Queue (declared at Client script) is locked for a Server when I add flag AMQP_EXCLUSIVE to it.
Here is my Server
// connect to server
$cnn = new AMQPConnection('...');
$cnn->connect();
$channel = new AMQPChannel($cnn);
// create exchange
$exchangeName = 'k-exchange';
$exchange = new AMQPExchange($channel);
$exchange->setName($exchangeName);
$exchange->setType(AMQP_EX_TYPE_DIRECT);
$exchange->declare();
// declare queue to consume messages from
$queue = new \AMQPQueue($channel);
$queue->setName('tempQueue');
$queue->declare();
// start consuming messages
$queue->consume(function($envelope, $queue)
use ($channel, $exchange) {
// create callback queue
$callbackQueue = new \AMQPQueue($channel);
$callbackQueue->setName($envelope->getReplyTo());
$callbackQueue->setFlags(AMQP_EXCLUSIVE); // set EXCLUSIVE flag
/* WARNING: Following code line causes error. See rabbit logs below:
* connection <0.1224.10>, channel 1 - error:
* {amqp_error,resource_locked,
* "cannot obtain exclusive access to locked queue 'amq.gen-Q6J...' in vhost '/'",
* 'queue.bind'}
*/
$callbackQueue->bind($exchange->getName(), 'rpc_reply');
// trying to publish response back to client's callback queue
$exchange->publish(
json_encode(array('processed by remote service!')),
'rpc_reply',
AMQP_MANDATORY & AMQP_IMMEDIATE
);
$queue->ack($envelope->getDeliveryTag());
});
And here is my Client.php
// connect to server
$cnn = new AMQPConnection('...');
$cnn->connect();
$channel = new AMQPChannel($cnn);
// create exchange
$exchangeName = 'k-exchange';
$exchange = new AMQPExchange($channel);
$exchange->setName($exchangeName);
$exchange->setType(AMQP_EX_TYPE_DIRECT);
$exchange->declare();
// create a queue which we send messages to server via
$queue = new \AMQPQueue($channel);
$queue->setName('tempQueue');
$queue->declare();
// binding exchange to queue
$queue->bind($exchangeName, 'temp_action');
// create correlation_id
$correlationId = sha1(time() . rand(0, 1000000));
// create anonymous callback queue to get server response response via
$callbackQueue = new \AMQPQueue($channel);
$callbackQueue->setFlags(AMQP_EXCLUSIVE); // set EXCLUSIVE flag
$callbackQueue->declare();
// publishing message to exchange (passing it to server)
$exchange->publish(
json_encode(array('process me!')),
'temp_action',
AMQP_MANDATORY,
array(
'reply_to' => $callbackQueue->getName(), // pass callback queue name
'correlation_id' => $correlationId
)
);
// going to wait for remote service complete tasks. tick once a second
$attempts = 0;
while ($attempts < 5)
{
echo 'Attempt ' . $attempts . PHP_EOL;
$envelope = $callbackQueue->get();
if ($envelope) {
echo 'Got response! ';
print_r($envelope->getBody());
echo PHP_EOL;
exit;
}
sleep(1);
$attempts++;
}
So in the end I just see error in RabbitMQ's logs:
connection <0.1224.10>, channel 1 - error:
{amqp_error,resource_locked,
"cannot obtain exclusive access to locked queue 'amq.gen-Q6J...' in vhost '/'",
'queue.bind'}
Question:
What is the proper way to create a callbackQueue object in a Server.php?
It appears that my Server.php has a different from Client.php connection to a RabbitMQ server. What should I do here?
How should I "share" the same (to Client.php's) connection at Server.php side.
UPDATE
Here are some more RabbitMQ Logs
My Server.php connection (Id is: <0.22322.27>)
=INFO REPORT==== 20-Jun-2012::13:30:22 ===
accepting AMQP connection <0.22322.27> (127.0.0.1:58457 -> 127.0.0.1:5672)
My Client.php connection (Id is: <0.22465.27>)
=INFO REPORT==== 20-Jun-2012::13:30:38 ===
accepting AMQP connection <0.22465.27> (127.0.0.1:58458 -> 127.0.0.1:5672)
Now I see Server.php causes error:
=ERROR REPORT==== 20-Jun-2012::13:30:38 ===
connection <0.22322.27>, channel 1 - error:
{amqp_error,resource_locked,
"cannot obtain exclusive access to locked queue 'amq.gen-g6Q...' in vhost '/'",
'queue.bind'}
My Assumption
I suspect since Client.php and Server.php do not share connection with the same Id it's impossible for them both to use exclusive queue declared in Client.php
There are a few issues with your implementation:
Exchange Declaration
Manually setting the reply queue opposed to
using a temporary queue
Use of AMQP_EXCLUSIVE in both directions
Exchange Declaration
You don't need to declare an exchange (AMQPExchange) to publish messages. In this RPC example, you need to use it as a way of broadcasting a message (e.g. temporary queue or temporary exchange). All communication will occur directly on the QUEUE and theoretically bypasses the exchange.
$exchange = new AMQPExchange($channel);
$exchange->publish(...);
QUEUEs & Reply To:
When you use AMQPQueue::setName() along with AMQPQueue::declare(), you are binding to a queue with a user defined name. If you declare the queue without a name, this is known as a temporary queue. This is useful when you need to receive a broadcasted message from a specific routing key. For this reason, RabbitMQ / AMQP generates a random temporary name. Since the queue name is made for a given instance to consume information exclusively, for its own sake, it is disposed of when the connection is closed.
When an RPC client wants to publish a message (AMQPExchange::publish()), it must specify a reply-to as one of the publish parameters. In this way, the RPC server can fetch the randomly generated name when it receives a request. It uses the reply-to name as the name of the QUEUE on which server will reply to the given client. Along with the temporary queue name, the instance must send a correlationId to ensure that the reply message it receives is unique to the request instance.
Client
$exchange = new AMQPExchange($channel);
$rpcServerQueueName = 'rpc_queue';
$client_queue = new AMQPQueue($this->channel);
$client_queue->setFlags(AMQP_EXCLUSIVE);
$client_queue->declareQueue();
$callbackQueueName = $client_queue->getName(); //e.g. amq.gen-JzTY20BRgKO-HjmUJj0wLg
//Set Publish Attributes
$corrId = uniqid();
$attributes = array(
'correlation_id' => $corrId,
'reply_to' => $this->callbackQueueName
);
$exchange->publish(
json_encode(['request message']),
$rpcServerQueueName,
AMQP_NOPARAM,
$attributes
);
//listen for response
$callback = function(AMQPEnvelope $message, AMQPQueue $q) {
if($message->getCorrelationId() == $this->corrId) {
$this->response = $message->getBody();
$q->nack($message->getDeliveryTag());
return false; //return false to signal to consume that you're done. other wise it continues to block
}
};
$client_queue->consume($callback);
Server
$exchange = new AMQPExchange($channel);
$rpcServerQueueName = 'rpc_queue';
$srvr_queue = new AMQPQueue($channel);
$srvr_queue->setName($rpcServerQueueName); //intentionally declares the rpc_server queue name
$srvr_queue->declareQueue();
...
$srvr_queue->consume(function(AMQPEnvelope $message, AMQPQueue $q) use (&$exchange) {
//publish with the exchange instance to the reply to queue
$exchange->publish(
json_encode(['response message']), //reponse message
$message->getReplyTo(), //get the reply to queue from the message
AMQP_NOPARAM, //disable all other params
$message->getCorrelationId() //obtain and respond with correlation id
);
//acknowledge receipt of the message
$q->ack($message->getDeliveryTag());
});
AMQP_EXCLUSIVE
In this case, EXCLUSIVE is only used on the Rpc client's temporary queue for each instance so that it can publish a message. In other words, the client creates a disposable temporary queue for it self to receive an answer from the RPC server exclusively. This insures no other channel thread can post on that queue. It is locked for the client and its responder only. It's important to note that AQMP_EXCLUSIVE does not prevent the RPC server from responding on the client's reply-to queue. AMQP_EXCLUSIVE pertains to two separate threads (channels instances) trying to publish to the same queue resource. When this occurs, the queue is essentially locked for subsequent connections. The same behavior occurs with an exchange declaration.
#Denis: Your implementation in this case is correct up to a point
Bad - don't re-declare the Queue in the server. That's the client's job
$callbackQueue = new \AMQPQueue($channel);
$callbackQueue->setName($envelope->getReplyTo());
$callbackQueue->setFlags(AMQP_EXCLUSIVE); // set EXCLUSIVE flag
...
$callbackQueue->bind($exchange->getName(), 'rpc_reply');
You're trying to bind to a QUEUE called tempQueue. But you've already created a queue called tempQueue in the client.php. Depending on which service is started first, the other will throw an error. So you can cut out all of that and just keep the last part:
// trying to publish response back to client's callback queue
$exchange->publish(
json_encode(array('processed by remote service!')),
'rpc_reply', //<--BAD Should be: $envelope->getReplyTo()
AMQP_MANDATORY & AMQP_IMMEDIATE
);
Then modify the above by replacing:
'rpc_reply'
with
$envelope->getReplyTo()
Don't Declare a Queue Name on the client side
// create a queue which we send messages to server via
$queue = new \AMQPQueue($channel);
//$queue->setName('tempQueue'); //remove this line
//add exclusivity
$queue->setFlags(AMQP_EXCLUSIVE);
$queue->declare();
//no need for binding... we're communicating on the queue directly
//there is no one listening to 'temp_action' so this implementation will send your message into limbo
//$queue->bind($exchangeName, 'temp_action'); //remove this line
My answer from this question replied on the RabbitMQ Official mailing list
While not using the same library here you have the official tutorials ported to PHP
https://github.com/rabbitmq/rabbitmq-tutorials/tree/master/php
The problem in your code is that you declare queues with different options.
So as one reply say, if you declare queue A as durable, then every other declaration of that queue must be durable. The same for the exclusive flag.
Also you don't need to redeclare a queue to publish messages to it. As an RPC server you assume that the address sent in the 'reply_to' property is already present. I think is the responsibility of the RpcClient to make sure the queue where it is waiting for replies exists already.
Addendum:
Exclusivity in queues means that the only the channel that declared the queue can access it.
On your server you should also declare your queue as exclusive. Remember, RabbitMQ queues should have the same flag. For example if you declare queue that is set to "durable" the other end should also declare the queue a "durable" So on your server put a flag $callbackQueue->setFlags(AMQP_EXCLUSIVE); somewhat like that from your client.
Want to know the behavior of rabbitmq multiple publisher and consumer.
Does rabbitmq server gives one message to any one of the consumer at a time and other consumers are ideal at that time?
OR
Consumers pick any unattended message from queue, so that at a time, more than one consumers are consuming the message from queue?
Basically I am designing a database queue and do not want more than one inserts at a time.
A message from the queue will be delivered to one consumer only. Ie: once the message makes its way to the queue - it won't be copied (broadcasted) to multiple consumers.
If you want to do broadcast - you have to use multiple queues.
See this tutorial for more details:
http://www.rabbitmq.com/tutorial-two-python.html
yes , RabitMQ supports multiple publisher and consumer.
Multiple Publisher
For publishing a messsge to rabbitmqyou need to declare a factory and do a connection to the rabbitmq server.
then decare a chennel to rabbitmq
ConnectionFactory FACTORY = new ConnectionFactory
FACTORY.setUsername ("guest")
FACTORY.setPassword ("guest")
FACTORY.setVirtualHost ("\")
FACTORY.setPort (5572)
FACTORY.setHost ("localhost")
Connection connection=FACTORY.newConnection
Channel channel = connection.createChannel
the basic key to route a message is a routing key
channel.basicPublish(EXCHANGE_NAME, "Queue1", MessageProperties.PERSISTENT_TEXT_PLAIN, "msg1".getBytes)
channel.basicPublish(EXCHANGE_NAME, "Queue2", MessageProperties.PERSISTENT_TEXT_PLAIN, "msg2".getBytes)
these two messages will be published to a seperate queue as per the routing key as mention queue1 and queue2
2.Multiple Consumer
for multiple consumer we declare a queue and bind to a particular routing key
the the message to that routing key will be publishe to respected queue.
channel.exchangeDeclare(EXCHANGE_NAME, "direct", durable)
channel.queueDeclare("q1", durable, false, false, null)
channel queueBind ("q1", EXCHANGE_NAME,"queue1")// routing key = "queue1"
val q1Consumer = new QueueingConsumer(channel)
channel basicConsume ("q1", false, q1Consumer)
like this u can consume messages from first queue
and same goes for second queue but specify the routing key as "queue2"
channel.exchangeDeclare(EXCHANGE_NAME, "direct", durable)
channel.queueDeclare("q2", durable, false, false, null)
channel queueBind ("q2", EXCHANGE_NAME,"queue2") // routing key = "queue2"
val q2Consumer = new QueueingConsumer(channel)
channel basicConsume ("q2", false, q2Consumer)