I am developing a sample route
FROM: SOURCE ENDPOINT URI
TO: TRANS ENDPOINT URI // Error or Exception occurred at this TRANS endpoint
TO: TARGET ENDPOINT URI
Now I want to catch the Error Occured endpoint and pass it to my processor.
Could anyone please help me with this?
<route>
<from uri="file:C:/MINTS/Source/"/>
<to uri="file:C:/MINTS/TRANS/"/> <!-- EXCPECTION OCCURED -->
<to uri="file:C:/MINTS/TARGET/"/>
<onException>
<exception>java.lang.Exception</exception>
<handled>
<constant>true</constant>
</handled>
<!-- NEED TO CATCH FAILURE ENDPOINT URI AND PASS TO MY PROCESSOR BELOW-->
<process ref="MyExceptionProcessor" />
</onException>
</route>
You can use exchange properties:
CamelFailureEndpoint
example xml-dsl: <exchangeProperty>CamelFailureEndpoint</exchangeProperty>
example java: exchange.getProperty(Exchange.FAILURE_ENDPOINT, String.class);
CamelToEndpoint
example xml-dsl: <exchangeProperty>CamelToEndpoint</exchangeProperty>
example java: exchange.getProperty(Exchange.TO_ENDPOINT, String.class)
The first one should print uri for the consumer endpoint (from) that failed and the second one should show the previously called producer (to) endpoint.
One handy way to debug contexts of an failed exchange is to use:
<to uri="log:loggerName?showAll=true" />
This will log all exchange properties, headers, body and exception which can help to understand what information is available within exchange. Be careful where you use it as it might also log secrets and passwords if they're within the exchange so better use it only locally during development.
For more information you'd probably need to access CamelMessageHistory exchange property through processor, bean or something.
Related
I have my camel setup along the lines of:
<route>
<from ur="servlet:///test"/>
<to uri="direct:check1"/>
<to uri="direct:check2"/>
<to uri="direct:check3"/>
<to uri="direct:myprocessor"/>
</route>
Since I'm setting this up as a request/reply (in-out) pattern, I'm confused around if there is a process-stopping issue on check1, 2, or 3 on one specific message/exchange how to 'fast fail' a response back without going through the rest of the routes?
Throwing exceptions and using the onException DSL will achieve what you need. If you throw an exception in one of the checks it will be caught in the onException block without going further through the rest of the route.
I have two routes - each in a different camel context:
<camelContext id="camelContext1" xmlns="http://camel.apache.org/schema/blueprint">
<onException>
<exception>com.me.MyException</exception>
<to uri="log:osgiExecutorLog"/>
</onException>
<route id="MyRoute">
<from uri="amq:test" />
<to uri="direct:MyDirect"/>
</route>
</camelContext>
<camelContext id="camelContext2" xmlns="http://camel.apache.org/schema/blueprint">
<route id="MyRoute">
<from uri="direct:MyDirect" />
<process ref="myProc"/>
</route>
</camelContext>
There are conditions where myProc will throw MyException and I want the onException in camel context 1 to catch that. I tried my luck hard but could not get that to work; is it like catching exceptions across camel contexts not supported or am I missing something?
Instead of trying to throw an exception back to the other context (which may or may not even be possible due to the mechanisms in camel 2.x) you could catch the exception and send a message to some sort of error handling endpoint.
This can be easily defined in a different route builder or context, as long as you know the endpoint name.
Each route then has exactly the same boilerplate exception handler at the top, for example:
onException(Exception.class).handled(true).to("direct-vm:errors")
We routinely use this sort of custom error handling between different route builders (in the same context, but the pattern can apply across contexts just as easily).
In our application, for example, we catch the exceptions, aggregate them in a list, and whenever 15 seconds goes by without a new exception we send an email via smtp - all too easy with a camel route defined as from("direct:errors")...
I want to use Camel to take a message from ActiveMQ and then, based on the message contents (a protobuf), send one or more messages to Twitter. I've written a bean that is called from within a route and which uses injection to send multiple messages to a "direct:xyz" endpoint.
However, Camel is complaining at runtime that:
2012-11-16 09:56:33,376 | WARN | ication.twitter] | DirectProducer | 160 - org.apache.camel.camel-core - 2.10.2 | No consumers available on endpoint: Endpoint[direct://twitter] to process: Exchange[Message: hello world]
If I instead inject directly to the Twitter endpoint from within the bean, it works fine. However, in order to ease testing, simplify configuration etc, I'd like to keep the actual Twitter config separate, hence wanting to send to a separate route.
The camel context config looks like:-
<camelContext id="NotificationTwitter"
trace="false" xmlns="http://camel.apache.org/schema/blueprint">
<dataFormats>
<protobuf id="notificationProto" instanceClass="org.abc.schemas.protobuf.NotificationDef$NotificationMsg" />
</dataFormats>
<route id="TwitterPreparation">
<from uri="activemq:notification.twitter" />
<unmarshal ref="notificationProto" />
<log logName="abc" loggingLevel="INFO"
message="Twitter request received: ${body}" />
<bean ref="NotificationTweeter" method="createTweets" />
</route>
<route id="Twitter">
<from uri="direct:twitter" />
<log logName="abc" loggingLevel="INFO"
message="Tweeting: ${body}" />
<to uri="twitter://timeline/user?consumerKey=itsasecret&consumerSecret=itsasecret&accessToken=itsasecret&accessTokenSecret=itsasecret" />
</route>
</camelContext>
The bean looks like:-
public class NotificationTweeter {
#EndpointInject(uri = "direct:twitter")
private ProducerTemplate producerTemplate;
public void createTweets(NotificationMsg notification) {
String tweet = notification.getMessageDetail().getTitle();
try {
// only send tweets where the notification message contains the Twitter mechanism
for (MechanismMsg mechanism : notification.getMechanismList()) {
if (mechanism.getType() == MechanismTypeEnum.TWITTER) {
// Cycle round the recipients
for (RecipientMsg recipient : mechanism.getRecipientList()) {
tweet = "#" + recipient.getIdentifier() + " " + tweet;
producerTemplate.sendBody(tweet);
}
// TODO exceptions if no recipients found, etc
}
}
} catch (Exception ex) {
ex.printStackTrace();
}
}
}
I've had this problem in other routes (it's certainly not related to the Twitter feature) but have just worked around it. This time, however, I'd like to actually understand what the issue is! Any help gratefully received, thanks.
According to your setup, it might also depend on the CamelContext you have picked up. I got the same error message because I was sending messages on a route that existed in another CamelContext than the one I actually was using.
(Although the previous answer was already accepted, this might be the working solution for other people searching for that error message.)
It sounds like a problem with the startup ordering of your routes. See more detail here http://camel.apache.org/configuring-route-startup-ordering-and-autostartup.html
You can configure the "direct" route to start before the other route, then that issue should be resolved.
For others coming here, this error can also be caused by an OSGI error for a dependency that has not been deployed.
A bit late to the party but this error happened to me when I had two separate blueprint files, one for normal running and one for test. In my test I was referring to the test blueprint but noticed that the normal one was also automatically started which caused errors.
In the documentation http://camel.apache.org/blueprint-testing.html it says you can disable certain bundles from starting up. That helped me in my case.
This can also be caused by having a . in the route name. Replace my.Route.Name with myRouteName fixed the issue for me.
I would like to know if it's possible with Camel to do throttling based on the content of the exchange.
The situation is the following: I have to call a webservice via soap. Among, the parameters sent to that webservice there is a customerId. The problem is that the webservice send back an error if there are more than 1 request per minute for a given customerId.
I'm wondering if it would be possible to implement throttling per customerId with Camel. So the throttling should not be implemented for all messages but only for messages with the same customerId.
Let me know how I could implement this or if I need to clarify my question.
ActiveMQ Message Groups is designed to handle this case. So, if you can introduce a JMS queue hop in your route, then just set the JMSXGroupId header to the customerId. Then in another route, you can consume from this queue and send to your web service to get the behavior you described.
also see http://camel.apache.org/parallel-processing-and-ordering.html for more information...
While ActiveMQ Message Groups would definitely address the parallel processing of unique customer ID's, in my assessment Claus is correct that introducing a throttle for each unique group represents an unimplemented feature for Camel/ActiveMQ.
Message Groups alone will not meet the SLA described. While each group of messages (correlated by the customer ID) will be processed in order with one thread per group, as long as requests take less than a minute to receive a response, the requirement of one request per minute per customer would not be enforced.
That said, I would be very interested to know if it would be possible to combine Message Groups and a throttle strategy in a way that would simulate the feature request in JIRA. My attempts so far have failed. I was thinking something along these lines:
<route>
<from uri="activemq:pending?maxConcurrentConsumers=10"/>
<throttle timePeriodMillis="60000">
<constant>1</constant>
<to uri="mock:endpoint"/>
</throttle>
</route>
However, the throttle seems to be applied to the entire set of requests moving to the endpoint, and not to each individual consumer. I have to admit, I was a bit surprised to find that behavior. My expectation was that the throttle would apply to each consumer individually, which would satisfy the SLA in the original question, provided that the messages include the customer ID in the JMSXGroupId header.
I came across a similar problem and finally came up with the solution described here.
My assumptions are:
Order of messages is not important (though it can be solved by re-sequencer)
Total volume of messages per customer ID is not great so the runtime is not saturated.
The solution approach:
Run aggregator for 1 minute while using customerID to assemble messages with the same customer ID into a list
Use Splitter to split the list into individual messages
Send the first message from the splitter to the actual service
Re-route the rest of the list back into the aggregator.
Java DSL version is a bit easier to understand:
final AggregationStrategy aggregationStrategy = AggregationStrategies.flexible(Object.class)
.accumulateInCollection(ArrayList.class);
from("direct:start")
.log("Receiving ${body}")
.aggregate(header("customerID"), aggregationStrategy).completionTimeout(60000)
.log("Aggregate: releasing ${body}")
.split(body())
.choice()
.when(header(Exchange.SPLIT_INDEX).isEqualTo(0))
.log("*** Processing: ${body}")
.to("mock:result")
.otherwise()
.to("seda:delay")
.endChoice();
from("seda:delay")
.delay(0)
.to("direct:start");
Spring XML version looks like the following:
<!-- this is our aggregation strategy defined as a spring bean -->
<!-- see http://stackoverflow.com/questions/27404726/how-does-one-set-the-pick-expression-for-apache-camels-flexibleaggregationstr -->
<bean id="_flexible0" class="org.apache.camel.util.toolbox.FlexibleAggregationStrategy"/>
<bean id="_flexible2" factory-bean="_flexible0" factory-method="accumulateInCollection">
<constructor-arg value="java.util.ArrayList" />
</bean>
<camelContext xmlns="http://camel.apache.org/schema/spring">
<route>
<from uri="direct:start"/>
<log message="Receiving ${body}"/>
<aggregate strategyRef="_flexible2" completionTimeout="60000" >
<correlationExpression>
<xpath>/order/#customerID</xpath>
</correlationExpression>
<log message="Aggregate: releasing ${body}"/>
<split>
<simple>${body}</simple>
<choice>
<when>
<simple>${header.CamelSplitIndex} == 0</simple>
<log message="*** Processing: ${body}"/>
<to uri="mock:result"/>
</when>
<otherwise>
<log message="--- Delaying: ${body}"/>
<to uri="seda:delay" />
</otherwise>
</choice>
</split>
</aggregate>
</route>
<route>
<from uri="seda:delay"/>
<to uri="direct:start"/>
</route>
</camelContext>
I'm trying to retrieve the stacktrace from the onException handler in Apache Camel:
<onException>
<exception>java.lang.Exception</exception>
<handled>
<constant>true</constant>
</handled>
<setHeader headerName="exception">
<simple>${exception}</simple>
</setHeader>
</onException>
However, the above only shows the exception rather than the entire stacktrace.
I understand that Camel stores the caught exception as a property on the Exchange with the key: Exchange.EXCEPTION_CAUGHT, but how can this be retrieved from the camel context routes file ?
Use exception.stacktrace to get the stacktrace. See the variables listed in the table at this page: http://camel.apache.org/simple
<simple>${exception.stacktrace}</simple>
There is also a ${exception.message} to refer to the exception message itself.