My Glassfish server is up and running and I can run simple JMS client programs that send and retrieve messages to queues and topics that are configured in the Glassfish console manually.
I'm busy writing a simple JMSBrowser to study JMS and would like to find out how I can retrieve from a java client the names of the administered objects Server objects (ConnectionFactory, Queues & Topics).
For example I have ConnectionFactory with JNDI name jms/__defaultConnectionFactory, a Queue jms/GlassFishBookQueue and a topic jms/GlassFishBookTopic.
How can I retrieve these names, when I only know there resource types (javax.jms.ConnectionFactory, javax.jms.Queue and javax.jms.Topic)
In this example I have one of every kind, but each could of course be a list.
Spent a lot of time trying to figure it out, to no avail.
It should be possible as any JMSBrowser present this information, so for instance this screen shot:
https://sourceforge.net/projects/jmstoolbox/
Any hint would be appreciated.
I'm the author of JMSToolBox
The JMS specs does not define a way to play with JMS artefacts defined in a server, ie create/delete/list..Queues/Topics/factories etc
Each Queue Manager has it's own proprietary way to expose those features. In JMSToolBox, I usually use JMX for that (with the help of proprietary MBeans..), but sometimes it is proprietary code to connect and list those objects.
If you connect to the Queue manager server via JNDI, there is probably a way to list all the JMS artefacts from the JNDI tree, and based on some proprietary pattern, determine what "kind" of object they represent(Queue, ConnectionFactory etc..)
BTW, GlassFish embeds OpenMQ. Here is the way it is done in JMSToolBox
I hope this helps
Related
Just for testing purpose, I want to automate scenario where I need to check Kafka messages content, so just wanted to know if it is possible to read messages without consumers directly from TOPIC using Kafka java libraries?
I'm new to Kafka so any suggestion will be good for me.
Thanks in advance!
You could SSH to the broker in question, then dump the log segments into a deserialized fashion, but it would take less time to simply use a consumer in any language, not necessarily Java
"For testing purposes" Kafka Java API provides MockProducer and MockConsumer, which are backed by Lists, not a full broker
We have multiple web and windows applications which were deployed to different servers that we are planning to integrate using NservierBus to let all apps can pub/sub message between them, I think we using pub/sub pattern and using MSMQ transport will be good for it. but one thing I am not clear if it is a way to avoid hard code to set sub endpoint to MSMQ QueueName#ServerName which has server name in it directly if pub is on another server. on 6-pre I saw idea to set endpoint name then using routing to delegate to transport-level address, is that a solution to do that? or only gateway is the solution? is a broker a good idea? what is the best practice for this scenario?
When using pub/sub, the subscriber currently needs to know the location of the queue of the publisher. The subscriber then sends a subscription-message to that queue, every single time it starts up. It cannot know if it subscribed already and if it subscribed for all the messages, since you might have added/configured some new ones.
The publisher reads these subscriptions messages and stores the subscription in storage. NServiceBus does this for you, so there's no need to write code for this. The only thing you need is configuration in the subscriber as to where the (queue of the) publisher is.
I wrote a tutorial myself which you can find here : http://dennis.bloggingabout.net/2015/10/28/nservicebus-publish-subscribe-tutorial/
That being said, you should take special care related to issues regarding websites that publish messages. More information on that can be found here : http://docs.particular.net/nservicebus/hosting/publishing-from-web-applications
In a scale out situation with MSMQ, you can also use the distributor : http://docs.particular.net/nservicebus/scalability-and-ha/distributor/
As a final note: It depends on the situation, but I would not worry too much about knowing locations of endpoints (or their queues). I would most likely not use pub/sub just for this 'technical issue'. But again, it completely depends on the situation. I can understand that rich-clients which spawn randomly might want this. But there are other solutions as well, with a more centralized storage and an API that is accessed by all the rich clients.
Using the latest version of NServiceBus 4.4 I believe.
We are looking to implement NServiceBus and this section is using SQLServer as a transport. We want to pub/subscribe, which is fine but how would it work with scaling out the subscribers?
I have done a PoC where I ran the recieving endpoint of a SQLServer transport multiple times and when a message came in, the first instance of the running reciever got the message and processed it, resulting in the other process NOT processing it, which is correct.
In a pub/subscribe architecture using SQLServer, would this same method of running multiple instances of the subscriber work and since we are using a common queue (SQLServer) it will just sort itself out and not process the message multiple times?
When using SQL Server persistence, the subscribers for your events and messages are held in the Subscription table within the NServiceBus database, so you can check which endpoints are subscribing to what messages or events by viewing the contents of that.
It's worth noting that you can only publish "message" classes with NServiceBus that are implementing the IEvent interface (unless you make use of unobtrusive mode).
When you publish a message or event using bus.Publish, all subscribers to that type will subscribe to it, as long as the individual endpoint names are different.
More information from Particular Software is here:
And here.
I'd like to create a web service that an application server can contact to add itself to a list of servers implementing the application. Clients could then contact the service to get a list of servers. Something similar to how minecraft's heartbeats work for adding your server to the main server list.
I could implement it myself pretty easily, but I'm hoping someone has already created something like this.
Advanced features would be useful. Things like:
Allowing a client to perform queries on application-specific properties like the number of users currently connected to the server
Distributing the server list across more than one machine
Timing out a server's entry in the list if it hasn't sent a heartbeat within some amount of time
Does anyone know of a service like this? I know there are open protocols and servers for doing local-LAN service discovery, but this would be a WAN service.
The protocols I could find that had any relevance to your intended application are these:
XRDS (eXtensible Resource Descriptor Sequence).
XMPP Service Discovery protocol.
The XRDS documentation is obtuse, but you may be able to push service descriptions in XML format. The service type specification might be generic, but I get a headache from trying to decipher committee-speak.
The XMPP Service Discovery protocol (part of the protocol Formerly Known As Jabber) also looked promising, but it seems that even though you could push your service description, they expect it to be one of the services mentioned on this list. Extending it would make it nonstandard.
Finally, I found something called seap (SErvice Announcement Protocol). It's old, it's rickety, the source may be propriety, it's written in C and Perl, it's a kludge, but it seems to do what you want, kind-of.
It seems like pushing a service announcement pulse is such an application-specific and trivial problem, that almost nobody has considered solving the general case.
My advice? Read the protocols and sources mentioned above for inspiration (I'd start with seap), and then write, implement, and publish a generic (probably xml-based) protocol yourself. All the existing ones seem to be either application-specific, incomprehensible, or a kludge.
Basically, you can write it yourself though I am not aware if anyone has one for public (I wrote one over 10 yrs ago, but for a company).
database (TableCols: auto-counter, svr_name, svr_ip, check_in_time, any-other-data)
code to receive heartbeat (http://<you-app.com>?svr_name=XYZ&svr_ip=P.Q.R.S)
code to list out servers within certain check_in_time
code to do some housecleaning once a while (eg: purge old records)
To send a heartbeat out, you only need to send a http:// call, on Linux use wget* with crontab, on windows use wget.exe with task scheduler.
It is application specific, so even if you wrote one yourself, others can't use it without modifying the source code.
Is there any way in activemq with which we can get count number of messages
consumed/produced per second/minute at the broker end?
I have tried JMeter configuration using http://activemq.apache.org/jmeter-performance-tests.html but there is hardly any performance matrix I can gather.
thanks
If you wanted to write this yourself then you should use JMX on your broker. The Broker MBean has "TotalEnqueueCount" and "TotalDequeCount" attributes. You can poll at specific intervals for those values and calculate yourself how many messages a second/minute/hour that your broker is being produced to or consumed from.
You'll need to make sure you have JMX setup on the broker side, of course. See here for more details on that: http://activemq.apache.org/jmx.html
to simply view total enqueue/dequeue stats, use jconsole or the web console
if you need to process it further (to calculate rates, etc), then you should do one of the following:
access stats programmatically using Java JMX APIs and gather/process over time
use a third party tool for monitoring (Cacti and Splunk can also help with this)
another option is to use Camel Dataset to simulate data routing and gather stats