I'm using Camel within a Spring boot application and integrate with RabbitMQ but am encountering strange behaviour.
My app has Restful endpointswhich convert the http request to a RabbitMQ message and publish this to a predefined exchange. There is a separate consumer app which listens to a queue and processes the messages.
I have deliberately entered an incorrect rabbitmq exchange name (invalidxchangename)to check that the application will fail if the exchange does not exist however the camel context starts without error and when I send in a first request is does not report any error. This message gets lost as there is no matching RabbitMQ exchange. When I submit a second request I receive the following exception which I would have expected on route startup.
com.rabbitmq.client.AlreadyClosedException: channel is already closed due to channel error; protocol method: #method<channel.close>(reply-code=404, reply-text=NOT_FOUND - no exchange 'invalidxchangename' in vhost
EDIT:
I've tried a more simple example to show the issue in Camel.
I've created a simple route as follows:
from("file:in?fileName=in.txt").log(LoggingLevel.DEBUG, "in here!").to("rabbitmq://localhost:5762/invalidexchange?declare=false");
where there is an existing RabbitMQ exchange called validexchange (so I have deliberately made a typo in the RabbitMQ uri). I would expect the camel route to fail at startup since the exchange doesn't exist, or even the first time it tries to process a new in.txt file.
What I am actually seeing in the logs is that on start up it reports no error and only on the 2nd invocation of the route does it report an error.
2015-03-11 16:17:04.356 INFO 9756 : ID-SBMELW7W-06220-59960-1426051020468-0-2 >>> (route2) from(file://in?fileName=in.txt) --> log[in here!] <<< Pattern:InOnly, Headers:...
2015-03-11 16:17:04.360 INFO 9756 : ID-SBMELW7W-06220-59960-1426051020468-0-2 >>> (route2) log[in here!] --> rabbitmq://localhost:5762/customerchannel.exchang?declare=false <<< Pattern:InOnly, Headers:...
2015-03-11 16:17:45.073 INFO 9756 : ID-SBMELW7W-06220-59960-1426051020468-0-4 >>> (route2) from(file://in?fileName=in.txt) --> log[in here!] <<< Pattern:InOnly, Headers: ...
2015-03-11 16:17:45.079 INFO 9756 : ID-SBMELW7W-06220-59960-1426051020468-0-4 >>> (route2) log[in here!] --> rabbitmq://localhost:5762/customerchannel.exchang?declare=false <<< Pattern:InOnly, Headers:...
2015-03-11 16:17:45.092 ERROR 9756 : Failed delivery for (MessageId: ID-SBMELW7W-06220-59960-1426051020468-0-3 on ExchangeId: ID-SBMELW7W-06220-59960-1426051020468-0-4). Exhausted after delivery attempt: 1 caught: com.rabbitmq.client.AlreadyClosedException: channel is already closed due to channel error; protocol method: #method<channel.close>(reply-code=404, reply-text=NOT_FOUND - no exchange 'customerchannel.exchang' in vhost '/', class-id=60, method-id=40)
It looks like the first request is causing an error which closes the connection and logs the reason, and when you try to use the channel the second time it's returning an AlreadyClosedException with the message that caused the channel to close in the first call.
You can test this by trying to publish the second message to a different exchange name in the same channel and checking which exchange is in the error. E.g. publish the second message to invalidxchangename2 and you should still see invalidxchangename as the exchange in the error.
To fix, you should handle the publish result when you publish and re-establish the connection if there's an error.
If you want to be sure that a message got delivered to a RabbitMQ queue, then you have to use publisher confirms: https://www.rabbitmq.com/confirms.html
That you are able to publish a message it doesn't mean that the message will reach a queue. You could go to a mailbox and leave a letter inside, but between the time you left the letter there and a postman picked up, many things could have happened, for example, the mailbox catching fire and so on.
Related
My camel route tries to pick up some files from sftp, transfer them to network, and delete them from sftp. If the sftp is unreachable after 3 attempts, I want the route to send an email warning the admin about the problem.
For this reason my sftp address has the following parameters:
maximumReconnectAttempts=2&throwExceptionOnConnectFailed=true&consumer.bridgeErrorHandler=true
In case the network location is not available, i want the route to notify the admin and not delete the files from sftp.
For this reason i have set .handled(false) in onException.
However, when connecting to sftp fails, aggregation also fails and no emails are coming. I have made a minimalist example below:
/configure
onException(Throwable.class)
.retryAttemptedLogLevel(LoggingLevel.WARN)
.redeliveryDelay(1000)
.handled(false)
.log(LoggingLevel.ERROR, LOG, "XXX - Error moving files")
.to(AGGREGATEROUTE)
.end();
from(downloadFrom)
.to(to)
.log(LoggingLevel.INFO, LOG, "XXX - Moving file OK")
.to(AGGREGATEROUTE);
from(AGGREGATEROUTE)
.log(LoggingLevel.INFO, LOG, "XXX - Starting aggregation.")
.aggregate(constant(true), new GroupedExchangeAggregationStrategy())
.completionFromBatchConsumer()
.completionTimeout(10000)
.log(LoggingLevel.INFO, LOG, "XXX - Aggregation completed, sending mail.");
In the logs i see:
16:02| ERROR | CamelLogger.java 156 | XXX - Error moving files
Then the logs for the Exception occurring during connection.
And then this:
16:02| ERROR | FatalFallbackErrorHandler.java 174 | Exception occurred while trying to handle previously thrown exception on exchangeId: ID-LP0641-1552662095664-0-2 using: [Pipeline[[Channel[Log(proefjes.camel_cursus.routebuilders.MoveWithPickupExceptions)[XXX - Error moving files]], Channel[sendTo(direct://aggregate)]]]].
16:02| ERROR | FatalFallbackErrorHandler.java 172 | \--> New exception on exchangeId: ID-LP0641-1552662095664-0-2
org.apache.camel.component.file.GenericFileOperationFailedException: Cannot connect to sftp://user#mycompany.nl:22
at org.apache.camel.component.file.remote.SftpOperations.connect(SftpOperations.java:149)
I do not see "XXX - Starting aggregation." which i would expect to see in the log. Does some kind of error occur befor aggregation? The breakpoint on aggregate(*, *) is never reached.
First, I just want to clarify something. You write "In case the network location is not available, i want the route to notify the admin and not delete the files from sftp", but shouldn't that be obvious anyhow? I mean, if the network location is not available, wouldn't deleting the files from sftp be impossible?
It's a little confusing that your exception handler is also routing .to(AGGREGATEROUTE). Given that you want to email an admin, shouldn't that be in the exception handler, not in the happy path? Why would you and how would you "aggregate" a connection failure?
Finally, and here I think is a real problem with your implementation, you may have misunderstood what handled(false) does. Setting this to false means routing should stop and propagate the exception returned to the caller. I'm not sure what having to the .to(AGGREGATEROUTE) would do in this case, but I'm not surprised it's not being called.
I suggest trying a few things. I don't have your code so I'm not sure which will work best. These are all related and any might work:
Change handled(false) to handled(true).
Replace handled with continued(true).
Use a Dead Letter Channel.
Reference:
Handle and Continue Exceptions
Dead Letter Channel
Since errorhandling is different depending on which endpoint causes the error, i have solved this by having two different versions of onException:
//configure exception on sft end
onException(Throwable.class)
.maximumRedeliveries(2)
.retryAttemptedLogLevel(LoggingLevel.WARN)
.redeliveryDelay(1000)
.onWhen(new hasSFTPErrorPredicate())
// .continued(true) // tries to connect once, mails and continues to aggregation with empty exchange
//.handled(false) // tries to connect twice but does not reach mail
.handled(true) // tries to connect once, does reach mail
// handled not defined: tries to connect twice but does not reach mail
.log(LoggingLevel.INFO, LOG, "XXX - SFTP exception")
.to(MAIL_ROUTE)
.end();
// exception anywhere else
onException(Throwable.class)
.maximumRedeliveries(2)
.retryAttemptedLogLevel(LoggingLevel.WARN)
.redeliveryDelay(1000)
.log(LoggingLevel.ERROR, LOG, "XXX - Error moving file ${file:name}: ${exception}")
.to(AGGREGATEROUTE)
.handled(false)
.end();
Exceptions occuring at the sftp end are handled in the first onException, because there the hasSFTPErrorPredicate returns 'true'. All this predicate does is check if any exception or their cause has "Cannot connect to sftp:" in the message.
No rollback is required in this case because nothing has happened yet.
Any other exception is handled by the second onException.
Apache Camel is throwing Invalid Correlation Key exception when trying to aggregate messages from my AWS SQS queue.
The messages were placed in the queue using ZipSplitter and they all appear in the queue with matching "parentId" values (which I added using a random uuid as part of the splitting -I've tried CamelSourceFile as well). I get the Exception repeatedly until the retries are exhausted.
My aggregate expression:
from(--queue--).aggregate(header("parentId"), customAggregationStrategy).completionTimeout(3000).processor(new Processor() {...}.to(--next queue--);
There is no logging emitted from my customAggregationStrategy nor from any of the subsequent processors. It fails to aggregate:
... DeadLetterChannel - Failed delivery for (MessageId: ...). On Delivery attempt: 0 caught ...CamelExchangeException: Invalid correlation key. Exchange[ID...]
The delivery attempt is 0 through 9 for my retry attempts.
The infuriating thing is that the code works everywhere but locally...which you think would narrow things down, but neither the exception nor anything else logged sheds any light onto what is going on here.
You could try to use Camel simple language when expressing the correlation key, ie:
.aggregate(simple("${headers.parentId}", customAggregationStrategy)
This way, the exceptions might be silently ignored ?
Did you activate Camel tracer (http://camel.apache.org/tracer.html) to analyse your exchanges and ease the debugging ?
I suspect you have an Exchange which does NOT have the "parentId" header. If you want to skip them, just activate the ignoreInvalidCorrelationKeys option (see http://camel.apache.org/aggregator2.html)
I am using Apache Camel to assist with capturing message data emitted by a third party software package. In this particular instance, I only need to capture what is produced by the software, there is no receiver on the other end (really no "end" to go to).
So, I tried to set up a route with just the "from" endpoint and no "to" endpoint. Apparently this is incorrect usage as I received the following exception:
[2018-08-15 11:08:03.205] ERROR: string.Launcher:191 - Exception
org.apache.camel.FailedToCreateRouteException: Failed to create route route1 at: >>> From[mina:udp://localhost:9877?sync=false] <<< in route: Route(route1)[[From[mina:udp://localhost:9877?sync=false]] -... because of Route route1 has no output processors. You need to add outputs to the route such as to("log:foo").
at org.apache.camel.model.RouteDefinition.addRoutes(RouteDefinition.java:1063)
at org.apache.camel.model.RouteDefinition.addRoutes(RouteDefinition.java:196)
at org.apache.camel.impl.DefaultCamelContext.startRoute(DefaultCamelContext.java:974)
at org.apache.camel.impl.DefaultCamelContext.startRouteDefinitions(DefaultCamelContext.java:3301)
at org.apache.camel.impl.DefaultCamelContext.doStartCamel(DefaultCamelContext.java:3024)
at org.apache.camel.impl.DefaultCamelContext.access$000(DefaultCamelContext.java:175)
at org.apache.camel.impl.DefaultCamelContext$2.call(DefaultCamelContext.java:2854)
at org.apache.camel.impl.DefaultCamelContext$2.call(DefaultCamelContext.java:2850)
at org.apache.camel.impl.DefaultCamelContext.doWithDefinedClassLoader(DefaultCamelContext.java:2873)
at org.apache.camel.impl.DefaultCamelContext.doStart(DefaultCamelContext.java:2850)
at org.apache.camel.support.ServiceSupport.start(ServiceSupport.java:61)
at org.apache.camel.impl.DefaultCamelContext.start(DefaultCamelContext.java:2819)
at {removed}.Launcher.startCamel(Launcher.java:189)
at {removed}.Launcher.main(Launcher.java:125)
Caused by: java.lang.IllegalArgumentException: Route route1 has no output processors. You need to add outputs to the route such as to("log:foo").
at org.apache.camel.model.RouteDefinition.addRoutes(RouteDefinition.java:1061)
... 13 more
How do I set up a camel route that allows me to intercept (capture) the message traffic coming from the source, and not send it "to" anything? There is no need for a receiver. What would be an appropriate "to" endpoint that just drops everything it receives?
The exception suggestion of to("log:foo"). What does this do?
You can see if the Stub component can help
http://camel.apache.org/stub.html
Example:
from("...")
.to("stub:nowhere");
The exception suggestion of to("log:foo"). What does this do?
It sends your route messages to an endpoint with a component of type log:
(http://camel.apache.org/log.html) - component which basically dumps message contents (body and/or headers and/or properties) to your log file using appropriate log category.
If you just want to drop everything received, it's a good choice:
to("log:com.company.camel.sample?level=TRACE&showAll=true&multiline=true")
Apparently if you're under Linux or Unix, you can also redirect to /dev/null like in this example:
to( "file:/dev?fileName=null")
I am not sure it can be used on Windows but I don't think so.
Note that the syntax: to( "file:/dev/null") does not work as it point to a directory called null but with the fileName option it will work.
I have a Camel rest endpoint (Jetty) which validates and processes incoming requests. Besides specific Exception handlers (onException) it uses a DLQ error handler (errorHandler(deadLetterChannel...)) which is setup to retry 3 times - if unsuccessful the message is moved to the DLQ.
My question is, how do I still return a user friendly error message back to the client if an unexpected Exception occurs rather than the full Exception body? Is there some config I'm missing on the errorHandler?
I've tried to find some examples on the camel unit tests (DeadLetterChannelHandledExampleTest) and camel in action 2 (Chapter 11) but none seemed to have specific examples for this scenario.
Code is:
.from(ROUTE_URI)
.errorHandler(deadLetterChannel("{{activemq.webhook.dlq.queue}}")
.onPrepareFailure(new FailureProcessor())
.maximumRedeliveries(3)
.redeliveryDelay(1000))
.bean(ParcelProcessor.class, "process");
Thank you for your help!
Use a 2nd route as the DLQ, eg direct:dead and then send the message first to the real DLQ, and then do the message transformation afterwards to return a friendly response.
errorHandler(deadLetterChannel("direct:dead")
from("direct:dead")
.to("{{activemq.webhook.dlq.queue}}")
.transform(constant("Sorry something was wrong"));
My code consumes jms queue and through lb redirects to external http client.
I need to log original message for every failed delivery to local directory.
Problem is that onException is caught by each failover.
Is there any way how to achieve this?
Pseudo code:
onException(Exception.class).useOriginalMessage()
.setHeader(...)
.to("file...")
.setHeader(...)
.to("file...")
from("activemq...")
.process(...)
.loadBalance().failover(...)
.to("lb-route1")
.to("lb-route2")
.end()
.process()
.to("file...")
from("lb-route1")
.recipientList("dynamic url")
.end()
from("lb-route2")
.recipientList("dynamic url")
.end()
I have not tested this logic with multiple to statements, but when I have my list of endpoints in an array this logic functions just fine. I will attempt to deliver to the first endpoint, if I cannot I will attempt to deliver this to the second endpoint. If an exception occurs at the second endpoint it will propagate back to the route's error handler. If you need it to round robin instead, change the last false on the failover statement to a true.
String[] endpointList = {"direct:end1", "direct:end2"};
from("direct:start")
.loadbalance().failover(endpointList.length-1, false, false)
.to(endpointList);