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">
Related
<int:channel id="emailInputChannel"/>
<!-- Email Poller. Only one poller thread -->
<task:executor id="emailPollingExecutor" pool-size="1" />
<int-mail:inbound-channel-adapter id="pop3EmailAdapter" store-uri="pop3://${pop3.user}:${pop3.pwd}#${pop3.server.host}/Inbox"
channel="emailInputChannel" should-delete-messages="true" auto-startup="true" java-mail-properties="javaMailProperties">
<int:poller max-messages-per-poll="1" fixed-delay="${email.poller.delay}" task-executor="emailPollingExecutor"/>
</int-mail:inbound-channel-adapter>
<!-- Java Mail POP3 properties -->
<util:properties id="javaMailProperties">
<beans:prop key="mail.debug">true</beans:prop>
<beans:prop key="mail.pop3.port">${pop3.server.port}</beans:prop>
</util:properties>
This application polls for emails containing application file attachments which contain the data to process. The email attachments are sent typically a few a day and are relatively sporadic. Since the files contain data for bulk load, we resorted to this configuration with a single poller for the Inbound POP3 mail adapter. Having multiple pollers caused duplicate poller invocations to pull the same email while another poller is processing it. With this configuration, however, the single poller hangs after some time with no indications of the problem in the logs. Please review what is wrong with this configuration. Also, is there is an alternative way to trigger the email adapter (e.g cron etc at a periodic interval)? I am using Spring Integration 2.1
A hung poller is most likely caused by the the thread stuck in user code. I see you have mail.debug=true. If that shows no activity then a hung thread is probably the cause. Use us jstack to take a thread dump.
Yes, you can use a cron expression but that's unlikely to change things.
2.1 is extremely old but I still think a hung thread is the cause.
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.
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.
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.
I have a spring integration configuration where I am polling files from a directory and then processing those files in later steps.
I am using a dispatcher channel for processing steps which allows the poller thread to be released and return back to continue to do polling while processing steps are happening.
This works fine until the thread pool limit is reached, at that point because of CALLER_RUNS rejection policy when the poller submits the file to processing step it ends up doing the processing in the same thread as the poller which stops the polling process to be put on halt until this step is completed.
How can I c*ompletely decouple the two stages* of this process?
My thinking was to use two task-executors, one for polling and another for dispatcher but that doesn't seems to help.
<!-- Poll files from landing zone directory -->
<int-file:inbound-channel-adapter id="files" directory="${lz.dir.${ft}}" filename-regex=".*\.txt$">
<int:poller fixed-delay="3000" max-messages-per-poll="2" task-executor="pollingExecutor" />
</int-file:inbound-channel-adapter>
<int:bridge input-channel="files" output-channel="sourceFiles" />
<!-- Dispatch retrieved files -->
<int:channel id="sourceFiles">
<int:dispatcher task-executor="processingExecutor" />
</int:channel>
Basically I want the polling process to never stop. ANy help would be appreciated.
Thanks
Use a QueueChannel; the poller dumps the file into the queue an you have a poller on the other side pulling messages out of the queue.
The queue is unbounded by default.
Or, of course, you can use an unbounded queue in your executor.
But if your consumer(s) can't keep up, you'll eventually get into trouble.