I am trying to use selectors on an amqp with Azure Service Bus consumer. However, for some reason the route is also consuming messages that do not match the selector.
Here's an example:
This route generates messages and append a header:
<route id="MessageGenerator">
<from uri="timer:generator?delay=5000&period=5000"/>
<setHeader headerName="INSTANCE_ID">
<simple>{{env:INSTANCE_ID}}</simple>
</setHeader>
<to uri="amqp:queue:external_queue" />
</route>
While this route should consume only those that contain INSTANCE_ID matching 2 possible values: env:INSTANCE_ID or Any.
<route id="ExternalConsumer">
<from uri="amqp:queue:external_queue?selector=INSTANCE_ID IN ('{{env:INSTANCE_ID}}', 'Any')"/>
<log message="{{env:INSTANCE_ID}} consumed message with Instance ID: ${header.INSTANCE_ID}" logName="AMQP_TEST" loggingLevel="INFO"/>
</route>
But the the log shows that it is consuming any message, regardless of the selector specifying which ones.
Am I missing something?
Thanks!
Issue here was that Azure Service Bus does NOT support selectors on queues. I switched to topics, which already have filters per subscription.
Related
I am using Apache Camel's AMQP component to listen to messages from an ActiveMQ Artemis topic.
This application is run on Kubernetes with two replicas.
I've configured a durable subscription with a unique clientId per pod and a common subscription name:
<route autoStartup=true" id="myRoute">
<from id="_amqp_topic" uri="amqp:topic:xxx?connectionFactory=#amqpCF&disableReplyTo=true&transacted=false&subscriptionDurable=true&clientId={{container-id}}&durableSubscriptionName=eventSubscription"/>
<log loggingLevel="INFO" message="Received event: ${body}"/>
...
</route>
The problem is both pods receive the message, when only one of them should. I'm trying to achieve something similar to Kafka's consumer groups, where only one member of the group receives each message.
If you want only one subscriber to receive the message then the subscribers must share the same subscription. Therefore, you need to:
set subscriptionShared=true in your _amqp_topic uri
use the same client ID (i.e. don't use {{container-id}})
For example:
<route autoStartup=true" id="myRoute">
<from id="_amqp_topic" uri="amqp:topic:xxx?connectionFactory=#amqpCF&disableReplyTo=true&transacted=false&subscriptionDurable=true&clientId=myClientID&durableSubscriptionName=eventSubscription&subscriptionShared=true"/>
<log loggingLevel="INFO" message="Received event: ${body}"/>
...
</route>
Another option would simply to use a queue instead of a topic, e.g.:
<route autoStartup=true" id="myRoute">
<from id="_amqp_queue" uri="amqp:queue:xxx?connectionFactory=#amqpCF&disableReplyTo=true&transacted=false"/>
<log loggingLevel="INFO" message="Received event: ${body}"/>
...
</route>
I have created multiple routes(say department, Employee) which takes input from file system folders(say department, Empployee) and process those files.
Now, I want to make them dependent. So, if I upload both emp.csv and dept.csv in those folders then it will process department file first and once complete it will start processing file for employee.
is there any way in camel to achieve this.
I looked at Route startupOrdering and AutoStartup feature, but it will work only for the first time when starting routes. However, I need same behavior for entire route life.
Thanks.
<route id="b" xmlns="http://camel.apache.org/schema/spring">
<from uri="file:/home/dev/code/Integration/RunCamleExample/src/main/resources/csv/Department?repeatCount=1&noop=true&delay=10000"/>
<log message="Department data is : ${body}"/>
</route>
<route id="employee" xmlns="http://camel.apache.org/schema/spring">
<from uri="file:/home/dev/code/Integration/RunCamleExample/src/main/resources/csv/Employee?noop=true&delay=10000"/>
<log message="Employee data is : ${body}"/>
</route>
I suggest to use other logic to handle the task. Two simple ways to go:
Use pollEnrich
Use pollEnrich to collect extra resource (e.g. a file with known name in file system) once at the middle of a route
Flow: Collect department files (From Endpoint) --(for each department file from file system) -> collect single employee file (trigger pollEnrich once with known name) ----> do anything else (if any)
Use ControlBus
Use ControlBus component to control the status of routes (only one of the route in 'start' status)
Flow: Start route A --(when route A complete its goal)-> Suspend route A ---> Start route B --(when route B complete its goal)-> Suspend route B ---> Start route A [loop back to head]
Dependent route execution first can be achieved in Camel using "RouteContext".
Example: If route 'A' is executed before route 'B' then route 'A' should be defined as 'RouteContext' and route be is defined inside "camelContext" like below:
<routeContext id="A" xmlns="http://camel.apache.org/schema/spring">
<route id="A">
<from uri="file:/home/dev/code/Integration/RunCamleExample/src/main/resources/csv/Department?repeatCount=1&noop=true&delay=10000"/>
<log message="Department data is : ${body}"/>
</route>
</routeContext>
Then regular "camelContext" should be defined with reference to this routeContext first.
<camelContext id="test" xmlns="http://camel.apache.org/schema/spring">
<routeContextRef ref="A"/>
<route id="B">
<from uri="file:/home/dev/code/Integration/RunCamleExample/src/main/resources/csv/Employee?noop=true&delay=10000"/>
<log message="Employee data is : ${body}"/>
</route>
</camelContext>
I'm using a ActiveMQ Broker with built-in Camel Routes. I want to read a file after an Event received.
<pseudo>
from Event A
read File XY
to Event B with Body from File XY
</pseuod>
I simple tried moving files from a temporary directory based on an event but only event B is written. In the Log file are no Exceptions or Error messages.
<camelContext id="camel" xmlns="http://camel.apache.org/schema/spring">
<!-- You can use Spring XML syntax to define the routes here using the <route> element -->
<route>
<description>Example Camel Route</description>
<from uri="activemq:example.A"/>
<from uri="file://tmp/a?delete=true"/>
<to uri="file://tmp/b?overruleFile=copy-of-${file:name}"/>
<to uri="activemq:example.B"/>
</route>
</camelContext>
Update with working solution for single file:
<camelContext id="camel" xmlns="http://camel.apache.org/schema/spring">
<!-- You can use Spring XML syntax to define the routes here using the <route> element -->
<route>
<description>Example Camel Route</description>
<from uri="activemq:example.A"/>
<pollEnrich>
<constant>file:///tmp/a?fileName=file1</constant>
</pollEnrich>
<log message="file content ${body}"/>
<to uri="activemq:example.B"/>
</route>
</camelContext>
You need to use Content Enrichers for this. This is exactly what you are looking for.
<route>
<from uri="activemq:example.A"/>
<pollEnrich>
<constant>file://tmp/a?delete=true</constant>
</pollEnrich>
<to uri="activemq:example.B"/>
</route>
Please be aware that for camel version 2.15 or older
pollEnrich does not access any data from the current Exchange which
means when polling it cannot use any of the existing headers you may
have set on the Exchange. For example you cannot set a filename in the
Exchange.FILE_NAME header and use pollEnrich to consume only that
file. For that you must set the filename in the endpoint URI.
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 want to set the endpoint specific header value in Multicast component.
XML DSL as below:
<route>
<from uri="direct:testRoute"/>
<multicast strategyRef="MyAggregator" parallelProcessing="true">
<to uri="direct:call1"/> <!-- set the header MY_HEADER = "call_1" -->
<to uri="direct:call2/> <!-- set the header MY_HEADER = "call_2" -->
</multicast>
</route>
Basically in the response aggregation I want to know, to which service request this response belongs to.
I tried by doing this, but its not the correct way (parse exception):
<to uri="direct:call1">
<setHeader headerName="MY_HEADER"><simple>call1</simple></setHeader>
</to>
What I see from reading the documentation is that, multicast will copy the source Exchange and multicast each copy. So its a shallow copy of the Exchange and kind of reference shared between all the multicast recipient.
But here I am looking for specific header value for individual recipient.
How to do this? Any pointers?
You can't do that in the multicast route. But it should be simple in the direct route afterwards.
<route>
<from uri="direct:call1"/>
<setHeader headerName="MY_HEADER"><simple>call1</simple></setHeader>
.. do whatever
</from>
</route>
otherwise, if call1 is used for other things and you cannot know when to put the header once in that route, make a simple prep-route:
<route>
<from uri="direct:prepCall1"/>
<setHeader headerName="MY_HEADER"><simple>call1</simple></setHeader>
<to uri="direct:call1"/>
</from>
</route>
As a third option, even though you cannot place DSL (xml or java) in the multicast list, you can supply an "onPrepareRef" processor bean that adds the headers to your exchange. But one processor will handle all multicast endpoints.
There is a header with the key Exchange.TO_ENDPOINT that you can see which of the 2 endpoints the response is from.