My req. is to poll a directory for a specified time interval say 10 mins. If a file of a particular extension say *.xml is found in the directory then the it just consumes (i.e. picks and deletes) the file and prints the name else after the specified time (say 10 mins.) interval it sends out a mail that the file has not been picked (i.e. consumed) or the file has not come.
There are 2 options either I do it through Spring integration OR WatchService of Core Java. Following is the code in Spring Integration which I have written till now:
<int:channel id="fileChannel" />
<int:channel id="processedFileChannel" />
<context:property-placeholder location="localProps.properties" />
<int:poller default="true" fixed-rate="10000" id="poller"></int:poller>
<int-file:inbound-channel-adapter
directory="file:${inbound.folder}" channel="fileChannel"
filename-pattern="*.xml" />
<int:service-activator input-channel="fileChannel"
ref="fileHandlerService" method="processFile" output-channel="processedFileChannel"/>
<bean id="fileHandlerService" class="com.practice.cmrs.springintegration.Poll" />
The above code is successfully polling the folder for a particular file pattern. Now I have 2 things to do:
1) Stop polling after a particular time interval (configurable) say 10 mins.
2) Check whether a file with a particular extension is there in the folder ... if the file is there (it consumes and then deletes) else it sends an email to a group of people (email part is done.)
Please help me in the above 2 points.
You can use a Smart Poller to do things like that.
You can adjust the poller and/or take different actions if/when the poll results in a message.
Version 4.2 introduced the AbstractMessageSourceAdvice. Any Advice objects in the advice-chain that subclass this class, are applied to just the receive operation. Such classes implement the following methods:
beforeReceive(MessageSource<?> source)
This method is called before the MessageSource.receive() method. It enables you to examine and or reconfigure the source at this time. Returning false cancels this poll (similar to the PollSkipAdvice mentioned above).
Message<?> afterReceive(Message<?> result, MessageSource<?> source)
This method is called after the receive() method; again, you can reconfigure the source, or take any action perhaps depending on the result (which can be null if there was no message created by the source). You can even return a different message!
Related
I am working with a project which is using JMS listener to receive incoming message, and then route to different destination, currently the process only pick one destination among below 3 for each incoming message. so the xml configuration is written as below
<integration:router ref="jmsRouter" input-channel="jmsFilterOutput" default-output-channel="jmsRouterOutput" />
<integration:service-activator id="serviceActivator1" input-channel="input1"
ref="messageProcessService" method="callMsgProcessor1" />
<integration:service-activator id="serviceActivator2" input-channel="input2"
ref="messageProcessService" method="callMsgProcessor2" />
<integration:service-activator id="serviceActivator3" input-channel="sharedInput"
ref="messageProcessService" method="callMsgProcessor3" output-channel="reqChannel" />
among above 3 serviceActivator, the output-channel of the last one is defined as IBM mq in another xml configuration file.
now my job is to generate a different message from sharedInput, and send to a different queue in parallel
so I add a line as below
<integration:service-activator id="serviceActivator4" input-channel="sharedInput"
ref="messageProcessService" method="callMsgProcessorNew" output-channel="reqChannelNew" />
however when running JMS, the message from sharedInput only goes to callMsgProcessor3, and the populated message is sent to reqChannel only as well, and ignore my new destination. if I comment out the third service activator, sharedInput can go to callMsgProcessorNew, and route to new queue.
can anyone advise how I should configure to push the sharedInput go to two processors (callMsgProcessor3 and callMsgProcessorNew), and also sent to their corresponding output mq channel in parallel?
I googled online, seems router splitter or recipient list router can solve my problem? but still feeling confused after reading the related doc, and not sure how to configure it in my case. appreciate if someone can help provide a sample
please let me know if I need to provide more info to clarify the issue.
You can make a sharedInput as a PublishSubscribeChannel and have another service activator subscribed to it so the same message will go to both of them. After that you can make absolutely different flows and do whatever logic you need to parallel. See docs for more info: https://docs.spring.io/spring-integration/docs/current/reference/html/core.html#channel-implementations-publishsubscribechannel.
Also respective EIP determination : https://www.enterpriseintegrationpatterns.com/patterns/messaging/PublishSubscribeChannel.html
thanks for your reply, #Artem! I realized one thing, sharedInput only go to one destination is because it is one message. if I can duplicate the message, it will go to two destination. so I add recipient-list-router, and made change as below, and it worked!
<integration:recipient-list-router id="duplicateMsgRouter" input-channel="sharedInput"
timeout="1234"
ignore-send-failures="true"
apply-sequence="true">
<integration:recipient channel="channel1"/>
<integration:recipient channel="channel2"/>
</integration:recipient-list-router>
<integration:service-activator id="serviceActivator3" input-channel="channel1"
ref="messageProcessService" method="callMsgProcessor3" output-channel="reqChannel" />
<integration:service-activator id="serviceActivator4" input-channel="channel2"
ref="messageProcessService" method="callMsgProcessorNew" output-channel="reqChannelNew" />
I have the following configuration which uses Redis as message store. I don't have java code for this module, but only this configuration file. This configuration has the following functionality: When this module receives a message from input channel, it will check the Redis store, if the message doesn't exist (the expression will be evaluated to TRUE), the message will be sent to the output channel which will be put into Redis; if the message already exists (the expression is evaluated to False), the message will be discarded.
Suppose this module is called RedisModule, so i have a stream:
RedisMdule | log
The problem is that: when I sent messages to this module, in the log file, it shows the messages #2, #4, #6 etc, the first message is missing, so are the odd number messages. Are there anything I have missed in this configuration file ? Many Thanks.
<int:channel id="input"/>
<int:channel id="output"/>
<int:filter input-channel="input"
output-channel="output"
discard-channel="nullChannel"
expression="#metadataStore.get(payload) == null"/>
<int:outbound-channel-adapter channel="output"
expression="#metadataStore.put(payload, '')"/>
From big height it looks like you need Idempotent Receiver, which does exactly similar logic but in the atomic manner. See MetadataStoreSelector source code:
return this.metadataStore.putIfAbsent(key, value) == null;
So, you can configure an <idempotent-receiver> with your RedisMetadataStore and use payload as a key-expression option.
It isn't clear by your post how you get logs, because <int:outbound-channel-adapter> is one-way component.
Maybe you are there in the Spring XD? Where you use the output channel for your own purpose, but that really should be an output of your module.
That's really may the reason why you see only even messages, because odd are sent to your <int:outbound-channel-adapter> and the DirectChannel uses round-robin balancing strategy by default.
With the <idempotent-receiver> you should have only <bridge input-channel="input" output-channel="output"/> in your RedisMdule.
How to process files in separate threads?
There is a /local dir where files are being put by other means and new files with same name replace old ones.
I want move files from /local to /processing dir and activate some service. Further in the end of filter chain a cleanup task will remove files from /processing.
I made it working 1 by 1, but processing takes minutes so I'd like to
Add multithreading: i.e. Several files are moved and processed simultaneously.
If there is a file that was not yet processed say "File1.abc" and a new version of this file has been put to /local then no need to process old message with old version of file. I.e. messages should be sent only for version of files in the moment they are moved from /local to /processing
I am trying something like this:
<file:inbound-channel-adapter channel="processingChannel"
directory="#{localDir}"
prevent-duplicates="false" filter="acceptAllFileListFilter">
<int:poller fixed-rate="20" max-messages-per-poll="3" task-executor="executor"/>
</file:inbound-channel-adapter>
<task:executor id="executor" pool-size="3" queue-capacity="0" rejection-policy="ABORT"/>
<file:outbound-gateway request-channel="processingChannel" reply-channel="serviceChannel"
directory="#{processing}"
auto-create-directory="true"
filename-generator-expression="payload.name + '_' + { T(java.lang.System).currentTimeMillis()}"
delete-source-files="true"
mode="FAIL" />
<int:service-activator input-channel="serviceChannel" output-channel="furtherChannels"
ref="someService" method="process">
</int:service-activator>
<bean id="someService" class="com.dot.SomeService"/>
But it does not work and I cannot figure out how to fix it. I tried different ways but there are always errors like messages are generated for already deleted files or some other problems. The task itself seems simple. How to make files process in say 3 threads and send messages only for actual versions of files? Maybe problem here with polling consumer but inbound adapter is used only with this consumer, right?
I don't see solution for you yet, but maybe you just don't explain the challenge properly... Try just share the business requirements.
Plus I don't see reason for the <file:outbound-gateway>. You can just read files from the /local dir and process them. For the concurrency and some discard in-flight processes logic you could use some custom FileListFilter, from where you should determine the new file version and by its key cancel() the ran process to start a new one in the end of current poll().
There might be some other solution, but let's start just from the business requirements!
I'm writing a file polling implementation and am trying to determine if I need to use a AcceptOnceFileListFilter.
The first step the FileProcessor will perform is to move the file to another directory.
Does the poller "batchFilePoller" use multiple threads when polling? Can a race condition occur where a file will be read by multiple threads? In this case I assume I need to use the AcceptOnceFileListFilter.
However if the poller is only using one thread from the pool.
Then if the file is moved before the next poll time and it succeeds I assume there is no posability of the file been processed twice?
<int-file:inbound-channel-adapter id="batchFileInAdapter" directory="/somefolder" auto-create-directory="true" auto-startup="false" channel="batchFileInChannel" >
<int:poller id="batchFilePoller" fixed-rate="6000" task-executor="batchTaskExecutor" max-messages-per-poll="1" error-channel="batchPollingErrorChannel" />
</int-file:inbound-channel-adapter>
<int:channel id="batchFileInChannel"/>
<int:service-activator input-channel="batchFileInChannel" >
<bean class="com.foo.FileProcessor" />
</int:service-activator>
<task:executor id="batchTaskExecutor" pool-size="5" queue-capacity="20"/>
The <int-file:inbound-channel-adapter> has prevent-duplicates option which is true by default and it is your case since you don't provide any other options which prevent prevent-duplicates to be true.
And yes: any polling adapter is multi-threaded, if you use fixed-rate. In this case the new polling task can be run before a finish of previous one.
Even if it will be a single-threaded (using fixed-delay), the AcceptOnceFileListFilter must be there, because a new polling task doesn't know if file has been processed or not. And it reads the same file again.
AcceptOnceFileListFilter is exactly for those cases when you don't like to read the same file one more time. You can overcome that with <int:transactional synchronization-factory=""/> for the <poller> of the <int-file:inbound-channel-adapter>:
<int:transaction-synchronization-factory id="txSyncFactory">
<int:after-commit expression="payload.delete()"/>
</int:transaction-synchronization-factory>
and PseudoTransactionManager.
More info you can find in the Spring Integration Reference Manual.
I am using spring integration to download files and to process them.
<int-sftp:inbound-channel-adapter channel="FileDownloadChannel"
session-factory="SftpSessionFactory"
remote-directory="/home/sshaji/from_disney/files"
filter = "modifiedFileListFilter"
local-directory="/home/sshaji/to_disney/downloads"
auto-create-local-directory="true" >
<integration:poller cron="*/10 * * * * *" default="true"/>
</int-sftp:inbound-channel-adapter>
<integration:transformer input-channel="FileDownloadChannel"
ref="ErrorTransformer"
output-channel="EndChannel"/>
The execution is started by the poller.
It calls the "FileDownloadChannel" and then tries to download files from the sftp server.
I want to specify an output channel for this inbound-channel-adaptor but it doesnot have any output-channel attribute.
So i named the transformer with the same name as that of inbound-channel-adaptor so that it will also be called once poller starts.
My issue is that the transformer gets called before the download happens and hence transformer wont get any inputs to process and causes error.
Is there any way we can specify "order" attribute for this two tasks. or is there any workaround for the output-channel for the inbound-channel adaptor?.
I would really appreciate any help on this.
You need to read the Spring Integration Reference Manual and work through some sample applications.
Channel adapters don't have input and output channels, they have channels. Channel adapters either produce or consume a message (inbound Vs outbound) on their channel. Elements such as transformers, service activators etc, that receive a message and produce a reply, have input and output channels.
"My issue is that the transformer gets called before the download happens and hence transformer wont get any inputs to process and causes error."
This statement makes no sense to me; if there's no file yet, there's nothing to "call" the transformer with.
"attribute for this two tasks."
There are not two "tasks".
The poller thread invokes the inbound adapter; then, when a file arrives, it is sent as a message to the configured channel which, with your configuration, means the poller thread invokes the transformer with the message.
A Channel Adapter is a Message Endpoint that enables connecting a single sender or receiver to a Message Channel.
In your case, output channel is 'FileDownloadChannel'
<integration:channel id="FileDownloadChannel"/>
<int-sftp:inbound-channel-adapter channel="FileDownloadChannel" ...>
<integration:poller fixed-rate="10000"/>
</int-sftp:inbound-channel-adapter>
In order to execute your tasks in order, you can use the Message Handler chain as follows:
<integration:channel id="outputChannel"/>
<chain input-channel="FileDownloadChannel" output-channel="outputChannel">
<filter ref="someSelector" throw-exception-on-rejection="true"/>
<transformer ref="ErrorTransformer"/>
<service-activator ref="someService" method="someMethod"/>
</chain>