I read the documentation about camel jmx. In my case i want to expose some attributes and operations of a Producer (made a custom component).
There seems to be no example for jmx on producers and all screenshots showing jConsole i saw doesn't show a "folder" producers (while consumers and endpoints are present).
But i tried to annotate my producer class with #ManagedResource, #ManagedAttribute and #ManagedOperation but it doesn't work (or where to look in jconsole?)
Some ducumentations mention an interface to be implemented "ManagementAware" but this is deprecated.
So how to expose producers with jmx?
Related
How can I determine what, if any, ActiveMQ queue a camel route is a consumer of? The route is running as a bundle within Karaf.
You have to define it yourself. Every Camel route starts with a from statement. For ActiveMQ this would look somehow like this
from("activemq:queue:myAwesomeQueue")...
This route would create an ActiveMQ consumer that consumes every message arriving on the myAwesomeQueue.
The connection to the broker is "hidden" behind the activemq:. This is a Camel component (the ActiveMQ component) that needs to be configured to connect to the broker.
EDIT: Add operational perspective
Hawtio is a webconsole that uses Jolokia to get data. Jolokia makes JMX information available through a REST API.
If JMX is enabled, you can get loads of information about the CamelContext and/or ActiveMQ. For example the endpoint of an ActiveMQ consumer as in your case.
Unfortunately I can't upload a screenshot because the image domain of SO is blocked, but Google gives you lots of them.
Some AMQP enabled brokers like Microsoft Service Bus or ActiveMQ allow only one active producer or consumer per session. The Apache JMS Camel component seems not be able to handle this correctly, which result that JMS throws exceptions when processing InOut messages sent from e.g. Service Bus.
A small JMS test application with separate sessions for producer and consumer works nice. With using the same session, it run into the same problem.
Issue is rooted in the Spring JMS template, which is used as base for the Camel JMS implementation.
Does anybody know how to overcome that behavior?
You can define a 2nd JMS component and use that for the "other".
Or you can turn off any kind of connection pooling maybe.
If you use XML then you can define a 2nd jms component
<bean id="jms2" class="org.apache.camel.component.jms.JmsComponent"/>
I am new to the concepts of Camel and I would like someone to confirm my findings so far.
Please correct if wrong
The way I see it, Camel has Components, which can have several communication interfaces called Endpoints. A Component can communicate with another component by sending a message to on of its Endpoints, which then will use a Processor to deliver it to the destination. I also read about Routes but I am not sure what they are used for because they seem to overlap in function with Processors (aka, they seem to be the same thing?)
Camel Routes and Endpoints
http://java.dzone.com/articles/open-source-integration-apache
Please confirm if correct
So far I believe that a Component (C1) in machine A can use an Endpoint (E1) to communicate with another component (C2) using its endpoint (E2) in machine B, by using websockets:
http://camel.apache.org/how-do-i-configure-endpoints.html
I would be grateful if someone could enlighten me in the first question or confirm my second one. Also, is there a better way to communicate between machines that doesn't involve using webscokets?
Thanks in advance, Pedro.
A Route is what connects endpoints and processors together. When you define a route in Camel it starts with a Component that exposes a communication Endpoint, invokes processors that implement the business logic of the route, and then can output the Exchange (the message being processed) to another Endpoint that is exposed by another Component.
Certain components allow Camel routes to communicate with endpoints in different machines. For example, the JMS component can be used to communicate with other machines via JMS messages. However, some components are limited to communicating with endpoints within the same VM like the SEDA component.
Camel provides many different ways to send data between machines (Here is a list of a few of them off the top of my head):
AMQP
JMS
Amazon SQS
HTTP
Mina
Netty
Take a look at the Camel Components page for a complete list: http://camel.apache.org/components.html
Does Camel provide anything out of the box which tells if it is able to connect all endpoints?
These endpoints could be MQ, webservice etc.
If not then I have to write a servlet which will send test request to all the endpoints. I will be using multicast or splitter for this implementation.
From my experience Camel will only provide warning logs if a from() endpoint is not available since it is constantly trying to read from them. Every other endpoint won't be accessed until the exchange tries to use that endpoint. If your goal is to test if various resources are alive I believe you would need to create your own testing program. I don't think this will be implemented as a feature because typically applications build in error handling if a resource is down and definte appropriate behaviors.
If we're talking about producers, then no. If your route is sending messages to an amq or http4 endpoint for instance, camel with not automatically send TCP-packets on these connections for monitoring purposes. A common way to handle failure of external endpoints is by using "circuit breakers". Take a look at https://camel.apache.org/load-balancer.html. A more robust alternative, imho, is Netflix's Hystrix.
If you have a polling consumer, say a from:ftp://.. then the polling consumer will poll messages every n-th millisecond, and you'll get an error if the connection is broken.
First of all thanks to folks who are currently involved in the development of Camel, I am grateful for all the hard work they have put in.
I am looking for some design advice.
The architecture is something like this:
I have a bunch of Java classes which when instantiated are required to connect to each other and send messages using Apache Camel. The design constraints require me to create a framework such that all routing information, producers, consumers, endpoints etc should be a part of the camel-context.xml.
An individual should have the capability to modify such a file and completely change the existing route without having the Java code available to him.(The Java code would not be provided, only the compiled Jar would be)
For example in One setup,
Bean A ->Bean B->Bean C->file->email.
in another
Bean B->Bean A->Bean C->ftp->file->email
We have tried various approached, but if the originating bean is not implemented as a Java DSL, the messages rate is very high because camel constantly invokes Bean A in the first example and Bean B in the second(they being the source).
Bean A and Bean B originate messages and are event driven. In case the required event occurs, the beans send out a notification message.
My transformations are very simple and I do not require the power of Java DSL at all.
To summarize, I have the following questions:
1) Considering the above constraints, I do I ensure all routing information, including destination addresses, everything is a part of the camel context file?
2) Are there example I can look at for keeping the routing information completely independent of the java code?
3) How do I ensure Camel does not constantly invoke the originating bean?
4) Does Camel constantly invoke just the originating bean or any bean it sends & messages to irrespective of the position of the bean in the entire messaging queue?
I have run out of options trying various ways to set this up. Any help would be appreciated.
Read about hiding the middleware on the Camel wiki pages. This allows you to let clients use an interface to send/receive messages but totally unaware of Camel (no Camel API used at all).
Even better consider buying the Camel in Action book and read chapter 14 which talks about this.
http://www.manning.com/ibsen/
Save 41% on Manning books: Camel in Action or ActiveMQ in Action. Use code s2941. Expires 6th oct. http://www.manning.com/ibsen/
If you consider using ServiceMix of FuseESB, you might want to separate your routes in two parts.
First part would be the Event-driver bean that trigger the route. It could push messages to the ServiceNMR (see http://camel.apache.org/nmr.html).
The other part would be left to the framework users, using Spring DSL. It would just listen to message on the NMR (push by the other route) and do whatever they want with it.
Of course endpoint definition could be propertized using servicemix configuration service (see http://camel.apache.org/properties.html#Properties-UsingBlueprintpropertyplaceholderwithCamelroutes)