Hello,
I'm after some advice from people more experienced in Camel than
myself on what the correct way is to structure my route(s). My
program essentially does the following:
1. Downloads file from FTP server
2. Saves a copy of the file (for auditing purposes)
3. Does some additional (time consuming) processing on the data
Therefore my code is like:
from("ftp://myserver/toProcess?move=processed";)
.to("file://recievedData")
.to("direct://additionalProcessing");
I use the "move" option on the FTP component to move the file after
processing so it will not be processed again. My problem is often by
the time the processing (step 3) has completed the FTP connection is
closed, so the file can not be moved resulting in the following
exception stack trace:
org.apache.camel.component.file.GenericFileOperationFailedException:
File operation failed: null Connection is not open. Code: 221
at
org.apache.camel.component.file.remote.FtpOperations.buildDirectory(FtpOperations.java:290)
at
org.apache.camel.component.file.strategy.GenericFileProcessStrategySupport.renameFile(GenericFileProcessStrategySupport.java:106)
at
org.apache.camel.component.file.strategy.GenericFileRenameProcessStrategy.commit(GenericFileRenameProcessStrategy.java:88)
at
org.apache.camel.component.file.GenericFileOnCompletion.processStrategyCommit(GenericFileOnCompletion.java:124)
at
org.apache.camel.component.file.GenericFileOnCompletion.onCompletion(GenericFileOnCompletion.java:80)
at
org.apache.camel.component.file.GenericFileOnCompletion.onComplete(GenericFileOnCompletion.java:54)
at
org.apache.camel.util.UnitOfWorkHelper.doneSynchronizations(UnitOfWorkHelper.java:100)
at org.apache.camel.impl.DefaultUnitOfWork.done(DefaultUnitOfWork.java:228)
at org.apache.camel.util.UnitOfWorkHelper.doneUow(UnitOfWorkHelper.java:61)
at
org.apache.camel.processor.CamelInternalProcessor$UnitOfWorkProcessorAdvice.after(CamelInternalProcessor.java:613)
at
org.apache.camel.processor.CamelInternalProcessor$UnitOfWorkProcessorAdvice.after(CamelInternalProcessor.java:581)
at
org.apache.camel.processor.CamelInternalProcessor$InternalCallback.done(CamelInternalProcessor.java:240)
at org.apache.camel.impl.MDCUnitOfWork$MDCCallback.done(MDCUnitOfWork.java:205)
at org.apache.camel.processor.Pipeline.process(Pipeline.java:106)
at
org.apache.camel.processor.CamelInternalProcessor.process(CamelInternalProcessor.java:191)
at
org.apache.camel.component.seda.SedaConsumer.sendToConsumers(SedaConsumer.java:291)
at org.apache.camel.component.seda.SedaConsumer.doRun(SedaConsumer.java:200)
at org.apache.camel.component.seda.SedaConsumer.run(SedaConsumer.java:147)
at
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:722)
Caused by: java.io.IOException: Connection is not open
at org.apache.commons.net.ftp.FTP.sendCommand(FTP.java:474)
at org.apache.commons.net.ftp.FTP.sendCommand(FTP.java:608)
at org.apache.commons.net.ftp.FTP.sendCommand(FTP.java:582)
at org.apache.commons.net.ftp.FTP.pwd(FTP.java:1454)
at
org.apache.commons.net.ftp.FTPClient.printWorkingDirectory(FTPClient.java:2658)
at
org.apache.camel.component.file.remote.FtpOperations.buildDirectory(FtpOperations.java:267)
... 20 more
Therefore my thinking was I can just restructure the code so the file
is moved on the FTP server after I've saved a copy of it. I hoped I
would be able to achieve this by putting in a SEDA component:
from("ftp://myserver/toProcess?move=processed";)
.to("file://recievedData")
.to("seda://dataQueue")
from("seda://dataQueue")
.to("direct://additionalProcessing")
However this does not achieve what I want. The file will still not be
renamed on the FTP server until "additionalProcessing" completes. I
tried setting the SEDA component options "waitForTaskToComplete=Never"
and "exchangePattern=InOnly" in the hope that this may help but it
doesn't.
I thought of 2 ideas how I can achieve what I want (with my current
understanding of Camel), but I don't think either is the correct
solution (and I have not tested either yet). Solution 1 is to divide
it into 2 routes and write it to a temporary location:
from("ftp://myserver/toProcess?move=processed";)
.to("file://tempLocation");
from("file://tempLocation")
.to("file://recievedData")
.to("direct://aditionalProcessing")
This seems wrong as it adds the extra IO overhead. Solution 2 is to
use wiretap EIP as follows:
from("ftp://myserver/toProcess?move=processed";)
.to("file://recievedData")
.wiretap("direct:additionalProcessing");
However I keep getting the feeling the above solution would be a
misuse of the wiretap EIP. Does any one have any idea what the
correct way to do this in Camel would be?
Thanks in advance for any advice any one can give me.
Neil
