Jdbc based Queue Channel without poller. Possible? - spring-integration

I have a scenario where I would like to separate the flow into a number of transactions. I am using queue channels based on a JdbcChannelMessageStore to do so and that works excellent. Its robust and it just works. But because these Jdbc based queues (the database) are polled by the executors, I get a natural limitation on the throughput (I don't really want to configure the poller to poll every 1 millisecond). So my question is this, is there a way for the queue channel to notify the consumer of that channel that a new messages has been queued, and then trigger the "poller" to have a look in the database to see what has to be consumed?
So the simple scenario:
1. A queue channel where someone puts a message
2. A service activator that will process that message (in parallel)
<int:channel id="InputChannel">
<int:queue message-store="jdbcChannelStore"/>
</int:channel>
<task:executor id="TradeTransformerExecutor" pool-size="2-20" queue-capacity="20" rejection-policy="CALLER_RUNS"/>
<int:service-activator id="TradeConverter" input-channel="InputChannel" output-channel="TradeChannel" method="transform">
<beans:bean class="com.service.TradeConverter"/>
<int:poller task-executor="TradeTransformerExecutor" max-messages-per-poll="-1" receive-timeout="0" fixed-rate="100">
<int:transactional transaction-manager="dbTransactionManager"/>
</int:poller>
</int:service-activator>
<int:channel id="TradeChannel"></int:channel>
So how could I make this InputChannel notify the poller (or something else) to start executing the message right away and not wait for 100ms?
Also I don't want to use DirectChannels as I do want some persistence between defined flows for robustness reasons.
Cheers guys.
Jonas

There's no way to change a trigger on demand; you can have a dynamic trigger, but changes only take effect after the next poll.
Instead of using a JDBC-backed channel, consider using an outbound channel adapter to store the data and a JDBC outbound gateway (with just a query, no update).
Use a pub-sub channel and, after storing, send the message (perhaps via a bridged ExecutorChannel) to the gateway.
Alternatively, simply inject your queue channel into a service and invoke it via a <service-activator/>. You would need a pub-sub channel bridged to your queue channel, with the second subscriber being the service activator which, when it receives the message calls receive() on the channel.
Finally, consider using a JMS, or RabbitMQ backed-channel for high performance persistence instead - they are much better a queueing than a database.

Related

Acknowledeging a spring message

I have a spring integration application and I am using message driven channel adapter for consuming the messages. This is the definition of the adapter -
<jms:message-driven-channel-adapter id="messageAdapter" destination="inQueue"
connection-factory="connectionFactory"
error-channel="errorChannel"
concurrent-consumers="${consumer.concurrent-consumers}"
acknowledge="transacted"
transaction-manager="transactionManager"
channel="channel"
auto-startup="true"
receive-timeout="50000"/>
So this message goes to my core channel and then goes through a series of service activators. In between if there is a error than this message is moved to errorChannel where I handle the errors and decide on what needs to be done with this message. For one scenario I want the message to not rollback to the queue, is it possible? I am using 'transacted' in my adapter definition so I am not sure how to drive this behaviour. Any help is greatly appreciated!
You don't describe what the transactionManager bean is. If it's a JmsTransactionManager, remove it and the container will just use local transactions.
Then, the transaction will only roll back if the flow on the error-channel throws an exception. If that error flow exits normally ("consuming" the error), the transaction will not roll back.
If it's some other transaction manager (e.g. JDBC) then remove it and start the JDBC transaction later in the flow (i.e. don't synchronize the JMS and JDBC transactions; again using a local JMS transaction).

Should JmsTransactionManager be used when persisting from one JMS Queue to another JMS Queue

Requirement:
We need to retrieve a message from a JMS Queue(published by a different application) and persist the message in our JMS Queue. Need the entire flow to be transactional so in case a message cannot be persisted in the downstream JMS queue, message received from upstream JMS Queue should not be acknowledged.
My configuration is as below
<int-jms:message-driven-channel-adapter
id="MessageDrivenAdapter" channel=" jmsMessageChannel " destination="sourceDestination"
connectionFactory="CF1"
acknowledge="transacted"
/>
<int:channel id=" jmsMessageChannel " />
<int-jms:outbound-channel-adapter id="sendsomemsg"
channel=" jmsMessageChannel " destination=”finalDestination”
connectionFactory="CF2"
session-transacted="true" />
Do I need to use JmsTransactionManager in this scenario or should be above configuration suffice. We can handle duplicate messages so I believe we do not need an XA transaction.
You definitely need XA transaction here because you are using several separate transactional resources. Even if they both are JMS, that doesn't mean that they can share transaction.
OTOH you can try a solution like ChainedTransactionManager and chain two JmsTransactionManagers - one for each your JMS resource.
More info is in Dave Syer's article.
As long as you don't hand off to another thread (queue channel, task executor), and both components are using the same connection factory, the outbound operation will run in the same transaction as the inbound - the underlying JmsTemplatein the outbound adapter will use the same session that the listener container delivered the message on.

Spring Integration - Having 1 Message-driven-channel-adapter active in a cluster

Issue:
Have 1 active MDP (jmsIn below) attached to a single queue and keep the second clustered MDP on server 2 passive. I require only a single active process because I want to perform aggregation and not lose messages.
I have been reading about the control bus but since its a clustered environment , the channel id and jms:message-driven-channel-adapter id would have the save name on both servers. Is it possible for the control bus to deactivate on another server using JMX even though they have the id's? Or possibly have a check done first by the message-driven-channel-adapter to determine if there is already a connection active on the queue itself.
Message-driven-channel-adapter Sample Code:
<jms:message-driven-channel-adapter id="jmsIn"
destination="requestQueue"
channel="jmsInChannel" />
<channel id="jmsInChannel" />
<beans:beans profile="default">
<stream:stdout-channel-adapter id="stdout" channel="jmsInChannel" append-newline="true"/>
</beans:beans>
<beans:beans profile="testCase">
<bridge input-channel="jmsInChannel" output-channel="queueChannel"/>
<channel id="queueChannel">
<queue />
</channel>
</beans:beans>
There is no reason to worry about clustered singleton for the <message-driven-channel-adapter>, just because any queuing system (like JMS) is designed for the single consumer for the particular message. In other words independently of the number of processes on the queue, only one of them picks up the message and process it.
The Transaction semantics on JMS help you do not lose messages. If there is some Exception, the TX rallbacks and the message is returned to the queue and can be picked up by another consumer.
For the aggregator you really can use some distributed persistent MessageStore. Where all your consumer send their messages to the same <aggregator> component which just deals with the shared MS to do its own aggregation logic.

Using Control bus to stop message-driven-channel-adapter that uses transactional session

My requirement is to use transactional session with message-driven-channel-adapter (JmsMessageDrivenEndpoint). I am able to setup the configuration buy using sessionTransacted = true for DefaultMessageListenerContainer.
Work flow: receive a message -> call the service activator -> service activator calls dao class
On successful commit to database a commit() is called by spring framework and on any runtime exception a rollback() is called by spring framework. Which works just fine. When a rollback happens JMS Broker sends the message back again to my application.
For a specific type of exception in dao I want to add a message header (i.e redelivery time) so that JMS Broker will not send the message again right away. How can I do it?
For another specific type of exception in dao I want to use control bus to stop the end point (message-driven-channel-adapter) and before stopping it rollback the previous transaction. How can I do it?
Any one can help me out?
There is no wonder, how to use Control Bus for start/stop endpoints:
<int:control-bus input-channel="controlChannel"/>
<int-jms:message-driven-channel-adapter id="jmsInboundEndpoint"/>
<int:transformer input-channel="stopImsInboundEndpointChannel"
outbound-channel="controlChannel"
expression="'#jmsInboundEndpoint.stop()'"/>
Or you can send to the controlChannel the same command string from any place of your code.
But it doesn't matter that the last transaction will be rollbacked. It depends on your 'unit of work' (in other words - the behaviour of your service).
However you can, at the same time when you send 'stop command', mark current transaction for rollback:
TransactionAspectSupport.currentTransactionStatus().setRollbackOnly();
Another your question about 'adding some message header' is abnormal for Messaging at all.
If you change the message it will be a new one and you can't rollback message to the queue with some new info.
Of course, you can do it anyway and have new message. But you should resend it, not rollback. So, you should commit transaction anyway and send that new message somewhere (or to the same queue), but it will be new message as for Broker as well for your application. And one more time: for this case you have to commit transaction.
Not sure that it is very clear and I go right way in my asnwer, but hope it helps you a bit.
You cannot modify the message (add a header) before rollback. You could, of course, requeue it as a new message after catching the exception. Some brokers (e.g. ActiveMQ) provide a back-off retry policy after a rollback. That might be a better solution if your broker supports it.
You can use the control bus to stop the container, but you will probably have to do it asynchronously (invoke the stop on another thread, e.g. by using an ExecutorChannel on the control bus). Otherwise, depending on your environment you might have problems with the stop waiting for the container thread to exit, so you shouldn't execute the stop on the container thread itself.
Best thing to do is experiment.
Thanks Gary and Artem. The solution is working. I am using the below configuration:
<jms:message-driven-channel-adapter id="jmsMessageDrivenChannelAdapter" connection-factory="connectionFactory"
destination="destination" transaction-manager="jmsTransactionManager" channel="serviceChannel" error-channel="ultimateErrorChannel" />
<si:service-activator input-channel="ultimateErrorChannel" output-channel="controlChannel">
<bean class="play.spring.integration.TestErrorHandler">
<property name="adapterNeedToStop" value="jmsMessageDrivenChannelAdapter" />
<property name="exceptionWhenNeedToStop" value="play.spring.integration.ShutdownException" />
</bean>
</si:service-activator>
<si:channel id="controlChannel">
<si:dispatcher task-executor="controlBusExecutor" />
</si:channel>
<task:executor id='controlBusExecutor' pool-size='10' queue-capacity='50' />
<si:control-bus input-channel="controlChannel" />
Now my question is if I want to stop multiple inbound adapters how can I send a single message to control-bus for all these adapters?
I am going to study SpEL. Would appreciate if someone already know it.
Thanks

Competing Consumers

I want to configure a spring integration application so that if I put a number of tasks, each represented by one message, on a channel then one of a group of endpoints will pick the next task and process it. This would entail some thread pool executor service I guess.
Yes, use a dispatcher + task executor with the channel (aka ExecutorChannel). That way any endpoint (e.g. service-activator) consuming from the channel will be invoked asynchronously using dispatcher's thread pool.
In the following example, any messages landing on channel channel01 will be consumed by the jobLauncher service within one of the taskExecutor threads.
<int:channel id="channel01">
<int:dispatcher task-executor="taskExecutor">
</int:channel>
<task:executor id="taskExecutor" pool-size="2"/>
<int:service-activator input-channel="channel01" ref="jobLauncher">

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