Hi all,
I’m relatively new (6 months) to ruby and jruby. At work we are
transitioning off of the .net stack to use java, jruby, rails and
glassfish
for some of our video on demand products (also I’m picking java up again
after 4 years on .net) . As part of this transition I am creating a
number
of infrastructure/utility components for my team to use. Specifically ,
I
am in the middle of using a service wrapper (wrapper.tanukisoftware.org)
to
create manageable ruby services. So far I can create a generic service
framework in ruby that calls out to the Java stuff (and likewise the
Java
stuff can call into the ruby stuff. Mostly this is just to support
start/stop/restart type of functionality).
Next on my plate is trying to get my Ruby code to hook up to JMX.
Specifically I would like to be able to create a ruby management bean
and be
able to register it with the platform mbean server. However I’m not
sure
I’ll be able to do it so before I go much further I was wondering if
anyone
can offer any thoughts on a) whether my approach is completely
untenable,
and is there a better approach that you would recommend, or b) what I am
trying to do is just not possible at the moment.
From reading about JMX it looks like there are lots of ways to skin the
cat.
I’ve looked around online and found a jmx4r gem but that only appears to
focus on being able to consume and display jmx endpoints. I’d like to
be
able to create ruby objects that bind themselves into the JMX management
server so they can be viewed. (if I can get this working I am hoping to
make
it generic enough that I’d like to add it to the jmx4r gem or other
opensource project 
if people think it might be useful)
If I were to go on the assumption that there is nothing out there I’ve
thought of a couple of ways I could attempt to do this but I’m not sure
they
will work. (however if there is something out there that someone knows
about please shout out )
My first thought is that it would be nice to create a ruby object that
implements the DynamicMBean interface. From there people could mixin a
module that exposes the management information. The problem I am
running
into is the types aren’t aligning when I register my ruby class as an
MBean
(I could share code if you are interested).
So I created the following example. (it’s gone through a couple of
incarnations) And let me be the first to say that I don’t completely
understand how to bridge from java to jruby and back so if you can point
me
to places I could get a deeper understanding that’d be great (Ive read
the
examples at the wiki).
I’ve created a ruby class that inherits from a DynamicBean I’ve created
(this example is loosely based on the example on calling Jruby from java
that’s on the Wiki :
Java:
public class ManageableMBean implements DynamicMBean {
public Object getAttribute(String arg0) throws
AttributeNotFoundException,
MBeanException, ReflectionException {
return null;
}
public AttributeList getAttributes(String[] arg0) {
return null;
}
public MBeanInfo getMBeanInfo() {
return null;
}
public Object invoke(String arg0, Object[] arg1, String[] arg2)
throws MBeanException, ReflectionException {
return null;
}
public void setAttribute(Attribute arg0) throws
AttributeNotFoundException,
InvalidAttributeValueException, MBeanException,
ReflectionException {
}
public AttributeList setAttributes(AttributeList arg0) {
return null;
}
}
Here is my Ruby code:
require ‘java’
class Manageable < Java::ManageableMBean
include javax.management.DynamicMBean #if I could get the call to
registerMBean to see my object as the java object it represents I might
be
able to remove this include
def getAttribute(attribute)
“name”
end
def getAttributes(attributes)
[“name”]
end
def getMBeanInfo
mbi = javax.management.MBeanInfo.new(self.class, “Sample Dynamic
MBean”, null, null, null)
puts “#{mbi.class}”
mbi
end
def invoke(actionName, params, signature)
end
def setAttribute(attribute)
end
def setAttributes(attributes)
end
def self.register_bean(bean)
mbs =
java.lang.management.ManagementFactory.getPlatformMBeanServer()
on = javax.management.ObjectName.new(“ruby:type=#{bean.class}”)
mbs.registerMBean(bean.java_class, on) #it would be nice to be
able to
coerce the ruby object in to the base java class
end
end
bean = Manageable.new
puts “name is #{bean.class}”
Manageable.register_bean(bean)
c = getc.chomp
Even if I could register the bean with the server I’m not sure this is
going
to work but I was thinking that creating a dsl in ruby would let me hide
the
dynamic nature of the mbean.
I might have to go back to the drawing board. Are there any
pointers/alternate paths I should be exploring?
Thanks!
Jay
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