Re: [opennms-devel] Fetching an Event in a NotificationStrategy

You are on the right track.  Create a daemon that will get instantiated
through configuration in service-configuration.xml.  Your daemon will
work with EventIpcManager to register for events and install itself as a
callback when the events come in.  You probably want to use something
that does nothing other than event processing as a base, and queued is
probably the best thing:

opennms-services/src/main/java/org/opennms/netmgt/queued

In jmx/Queued.java, you only need the getLoggingPrefix() and
getSpringContext() methods--the rest of what is in there is specific to
RRD handling.  The value returned from getSpringContext() refers to a
Spring context defined in
opennms-services/src/main/resources/beanRefContext.xml.   Let us know if
you have any problems figuring this out.

Lastly, here is a web page that discusses some of the details of the
Spring-loaded daemon infrastructure:

http://www.opennms.org/index.php/Using_AbstractSpringContextJmxServiceDaemon_to_dependency_inject_a_daemon

Good luck!


        - djg

On Fri, 21 Nov 2008 13:14:40 -0500, "Levin, Gary Marc"
<[email protected]> said:
> Nothing like sending in a request to get the brain going.
> 
> I found that I can use EventIpcManagerFactory to get an EventIpcManager
> to which I can register an EventListener of my own.  The only tricky part
> is figuring out a good place to arrange for the class to register itself.
>  Is there a clean way to do it?  At worst, I can have a
> NotificationStrategy registered that instantiates the listener.  A hack,
> but it works.
> 
> 
> 
> Gary Levin
> RRC 1N345
> Telcordia Technologies
> 
> 
> > -----Original Message-----
> > From: Levin, Gary Marc
> > Sent: Friday, November 21, 2008 12:35 PM
> > To: '[email protected]'
> > Subject: RE: Fetching an Event in a NotificationStrategy
> >
> > This is a follow-up to the previous question.  I found
> > org.opennms.netmgt.xml.event.Event, and I can get the event from
> > NotificationFactory based on the EventId in the notification.
> >  The problem
> > is that the event retrieved is incomplete.  It is missing the
> > parameters
> > (which are passed to the notification, because they appear in my
> > description).
> >
> > * No parameters show up in the xml produced by Event.marshal().
> > * Event.getParms() returns null
> > (1) Is this a bug in org.opennms.netmgt.xml.event.Event?
> > (2) Is this a bug in
> > org.opennms.netmgt.xml.event.NotificationFactory.getEvent()?
> > (Producing an
> > incomplete Event)
> > (3) Is there an alternative way to get the original event from the
> > notification? (I thought that EventFactory would be the way
> > to go, but that
> > is not accessible from a NotificationStrategy.)
> >
> >
> >
> >
> >
> >
> > I am trying to forward the event to another system.  If
> > necessary, I can put
> > enough information into the notification description so that
> > I can manually
> > construct the event, but it seems like a fragile solution.
> >
> >
> >
> >
> > If there is a way to capture the event *before* it gets to be a
> > notification, that would be even better.  An EventListener
> > would be ideal.
> > (This is where the Uses page would be very helpful.)  Is
> > there a way to
> > register a new EventListener?
> >
> >
> >
> >
> > Gary Levin
> > RRC 1N345
> > Telcordia Technologies
> >
> >
> > > -----Original Message-----
> > > From: Levin, Gary Marc [mailto:[email protected]]
> > > Sent: Friday, October 31, 2008 3:56 PM
> > > To: [email protected]
> > > Subject: [opennms-devel] Fetching an Event in a NotificationStrategy
> > >
> >
> >
> > I need to fetch the Event that triggered a Notification.  I
> > have written an
> > implementation of NotificationStrategy, which is correctly invoked by
> > notifd.  The notification places the eventId into the text
> > message, which is
> > included in the list of arguments passed to
> > NotificationStrategy.send().  I
> > log this information, so I am sure it is being received correctly.
> >
> > My code then extracts the eventId, parses it into an integer,
> > eid, and tries
> > calling EventFactory.getEvent(eid).  It gets to that point,
> > but the call
> > never returns.  I catch SQLException, and that is not thrown either.
> >
> > I tried catching Throwable and found the problem to be
> >         java.lang.NoClassDefFoundError:
> > org/opennms/web/event/EventFactory
> > I am guessing this is caused by the EventFactory being loaded
> > by a different
> > classloader than my NotificationStrategy.  This had me go
> > look for another
> > way to get the event, using the jars in lib and not web-apps.
> >
> >
> >
> > I was trying to learn more about the API and noticed that although
> >        http://www.opennms.org/documentation/java-apidocs-stable/
> >             org/opennms/netmgt/xml/event/Event.html
> > exists, if you go to the frame view, this class and its
> > package are not in
> > the list of packages and classes.
> >
> > I found that what I needed was
> > org.opennms.netmgt.xml.event.Event, which I
> > can get from
> > org.opennms.netmgt.xml.event.NotificationFactory.  This would
> > have been easier to find if the Javadoc included that
> > package.  Also,having
> > the Uses page when I am trying to learn an API.  This lets me
> > work backwards
> > from what I want, in this case an Event.
> >
> 
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