Monitoring Events in your BPEL Runtime - RSS Feeds?
- by Ramkumar Menon
@10g -
It had been a while since I'd tried something different. so here's what I did this week!Whenever our Developers deployed processes to the BPEL runtime, or perhaps when a process gets turned off due to connectivity issues, or maybe someone retired a process, I needed to know. So here's what I did.
Step 1: Downloaded Quartz libraries and went through the documentation to understand what it takes to schedule a recurring job.
Step 2: Cranked out two components using Oracle JDeveloper. [Within a new Web Project]
a) A simple Java Class named FeedUpdater that extends org.quartz.Job. All this class does is to connect to your BPEL Runtime [via opmn:ormi] and fetch all events that occured in the last "n" minutes. events? - If it doesn't ring a bell - its right there on the BPEL Console. If you click on "Administration > Process Log" - what you see are events.The API to retrieve the events is
//get the locator reference for the domain you are interested in.Locator l = ....
//Predicate to retrieve events for last "n" minutesWhereCondition wc = new WhereCondition(...)
//get all those events you needed.BPELProcessEvent[] events = l.listProcessEvents(wc);
After you get all these events, write out these into an RSS Feed XML structure and stream it into a file that resides either in your Apache htdocs, or wherever it can be accessed via HTTP.You can read all about RSS 2.0 here. At a high level, here is how it looks like.
<?xml version = '1.0' encoding = 'UTF-8'?><rss version="2.0"> <channel> <title>Live Updates from the Development Environment</title> <link>http://soadev.myserver.com/feeds/</link> <description>Live Updates from the Development Environment</description> <lastBuildDate>Fri, 19 Nov 2010 01:03:00 PST</lastBuildDate> <language>en-us</language> <ttl>1</ttl> <item> <guid>1290213724692</guid> <title>Process compiled</title> <link>http://soadev.myserver.com/BPELConsole/mdm_product/administration.jsp?mode=processLog&processName=&dn=all&eventType=all&eventDate=600&Filter=++Filter++</link> <pubDate>Fri Nov 19 00:00:37 PST 2010</pubDate> <description>SendPurchaseOrderRequestService: 3.0 Time : Fri Nov 19 00:00:37 PST 2010</description> </item>
......
</channel>
</rss>
For writing ut XML content, read through Oracle XML Parser APIs - [search around for oracle.xml.parser.v2]
b) Now that my "Job" was done, my job was half done. Next, I wrote up a simple Scheduler Servlet that schedules the above "Job" class to be executed ever "n" minutes. It is very straight forward.
Here is the primary section of the code.
try { Scheduler sched = StdSchedulerFactory.getDefaultScheduler();
//get n and make a trigger that executes every "n" seconds Trigger trigger = TriggerUtils.makeSecondlyTrigger(n); trigger.setName("feedTrigger" + System.currentTimeMillis()); trigger.setGroup("feedGroup"); JobDetail job = new JobDetail("SOA_Feed" + System.currentTimeMillis(), "feedGroup", FeedUpdater.class); sched.scheduleJob(job,trigger);
}catch(Exception ex) { ex.printStackTrace(); throw new ServletException(ex.getMessage()); }
Look up the Quartz API and documentation. It will make this look much simpler.
Now that both components were ready, I packaged the Application into a war file and deployed it onto my Application Server. When the servlet initialized, the "n" second schedule was set/initialized.
From then on, the servlet kept populating the RSS Feed file. I just ensured that my "Job" code keeps only 30 latest events within it, so that the feed file is small and under control. [a few kbs]
Next I opened up the feed xml on my browser - It requested a subscription - and Here I was - watching new deployments/life cycle events all popping up on my browser toolbar every 5 (actually n) minutes!
Well, you could do it on a browser/reader of your choice - or perhaps read them like you read an email on your thunderbird!.
