Re: [jopr-dev] Plugin Dependencies
by mazz＠redhat.com
(be prepared: this is a long email :)
First of all, the plugin/classloading system is not as robust as the Eclipse plugin system, so please don't assume if you can do it in Eclipse, you can do it in the Jopr plugin system :-)
Second, when you say:
"This package is not declared in Tomcat's <plugin name... package="org.jboss.on.plugins.tomcat" declaration and therefore it won't be loaded by the Axis plugin class loader."
this is an incorrect assumption. The package= attribute has no bearing on the classloading or what classes get shared. This is only used to allow for "shorthand" classnames in the descriptor. Any relative classnames (not fully qualified) specified in the descriptor will be assumed to be in that package. That is all it is used for.
Third, yes there is this concept of transative deps such that if you have plugin A depend on plugin B depend on plugin C then C classes are in A (because C's classloader is the parent of B's classloader which is in turn the parent to A's classloader).
Forth, if you have this:
<depends plugin="A" />
<depends plugin="B" useClasses="true" />
The only dependency on plugin "A" is its metadata - NOT its classes. In the Jopr plugin system, you can only have a "useClasses" dependency on ONLY ONE plugin. So do not assume you can access "A"s classes in your plugin - you can only inherit its metadata and resource types. You do have access to Plugin B's classes in addition to its metadata/resource types.
In the new classloader stuff introduced in trunk (not in any releases yet but it is explained in that wiki page I posted earlier), think of <depends> as a "required" dependency - i.e. your plugin will NOT be able to be deployed UNLESS plugins A and B are deployed. Think of the <runs-inside> as an inferred dependency - called an "optional dependency". If you only have an optional dependency on plugin "A" (i.e. you have a <runs-inside> on a plugin "A" resource type) you don't have to have plugin A deployed - its "optional". The old way (in the current release) you have to have a <depends> for any external resource type you specify in the descriptor. This forces you to ensure that "A" and "B" are deployed along with your plugin (which sometimes you don't want to require, which is one reason for the new way we implemented).
However, the new way still has the restriction of only ONE <depends> can have a "useClasses". That sounds restrictive, and it is, but in our experience it usually is not a blocker because usually, plugins that depend on other plugins can usually rely on stacked/transative dependencies. For example, you have this:
<depends plugin="JMX" />
<depends plugin="Tomcat" useClasses="true" />
You do not need to specify the dependency on JMX. Since Tomcat has a <depends plugin="JMX">, you pick it up by <depend>ing on Tomcat. You don't have to specify it too.
Your component code is probably going to monitor Axis using JMX - so you can use the JMX components and classes to do the work, in the same way Tomcat plugin monitors other Tomcat things. And because you are depending on Tomcat, you can INJECT your resource types directly into the Tomcat type hierarchy. This sounds like the piece you are missing. There are two types of extending the type hierarchy in Jopr - Injection and Extension. You want Injection because you want to INJECT a "Axis" server type inside the Tomcat Server.
For more on this Injection/Extension stuff, see: http://jopr.org/confluence/display/RHQ/AMPS-Plugin+Extensions
So, in your descriptor, I suspect you'll want something like this:
<depends plugin="Tomcat" />
<server name="Axis"
discovery="org.rhq.plugins.jmx.MBeanResourceDiscoveryComponent"
class="AxisComponent"
description="Embedded Axis server running in Tomcat">
<runs-inside>
<parent-resource-type name="Tomcat Server" plugin="Tomcat"/>
</runs-inside>
<plugin-configuration>
<c:simple-property name="objectName" readOnly="true" default="..the Axis MBean ObjectName here..."/>
<c:simple-property name="nameTemplate" default="Axis"/>
<c:simple-property name="descriptionTemplate" default="Embedded Axis server running in Tomcat"/>
</plugin-configuration>
... your metric definitions, operations, etc. that you want to support for managing Axis ...
</server>
If you still can't get it, I'd be interested in helping you get off the ground with this. Feel free to email me your current plugin (zipped up with the source) and I'll take a quick look.
Also, let me know what version of Jopr you are using.
Thanks,
John Mazz
----- Original Message -----
From: "Bruno Wassermann" <bruno.wassermann(a)googlemail.com>
To: "John Mazzitelli" <mazz(a)redhat.com>
Cc: "jopr-dev" <jopr-dev(a)lists.jboss.org>
Sent: Friday, July 31, 2009 6:36:30 AM GMT -05:00 US/Canada Eastern
Subject: Re: [jopr-dev] Plugin Dependencies
Okay, I think I figured it out. The Tomcat plugin class I want to reuse in the Axis plugin is in package org.jboss.on.plugins.tomcat.helper. This package is not declared in Tomcat's <plugin name... package="org.jboss.on.plugins.tomcat" declaration and therefore it won't be loaded by the Axis plugin class loader.
Two observations. One could argue that I shouldn't write Axis code as a separate plugin, but rather include it as a server in the Tomcat plugin. That would solve the problem and seems to follow the approach generally taken in Jopr. In that case, is there a guarantee that all Tomcat instances will have been discovered, before the discovery component for Axis servers gets called? If not, how do you deal with that?
Second, it might be nice to allow plugin developers to specify the packages they want exposed to other plugins (i.e. that will be loaded by A's plugin class loader, if it depends on B). If someone has already implemented some useful feature, it would seem better to reuse it instead of duplicating the code. There is a similar feature for Eclipse plugins. However, with Eclipse you will usually build a reference implementation exercising your plugins' extension points and hence have an opportunity to figure out which packages you need to expose like that and which ones can remain internal. How a developer of Jopr plugins can figure this out is not entirely clear.
-- Bruno
On Fri, Jul 31, 2009 at 10:58 AM, Bruno Wassermann < bruno.wassermann(a)googlemail.com > wrote:
Hm,
I checked the plugin name in my depend, added an explicit useCases=true, but it still doesn't have TomcatConfig loaded at runtime. Is there, like for Eclipse plug-ins, a concept of internal and external (visible to other plugins that have some relationship with this plugin) classes and packages? I haven't seen any evidence for that, but just checking.
Are dependencies transitive? If we have plugins A, B, C and B depends on C and A depends on B and C, is it sufficient for A to declare its dependency on B with the dependency on C being implied?
Here's an excerpt from Axis' rhq-plugin.xml. Maybe you can spot something obvious that's wrong here?
<plugin
name="Axis"
displayName="Axis Server"
package="uk.ac.ucl.cs.sse.plugins.axis"
description="Discovery, measurment and management of Axis and deployed Web services"
xmlns:xsi=" http://www.w3.org/2001/XMLSchema-instance "
xmlns="urn:xmlns:rhq-plugin"
xmlns:c="urn:xmlns:rhq-configuration">
<depends plugin="JMX" />
<depends plugin="Tomcat" useClasses="true" />
<server
name="Axis Server"
...
-- Bruno
On Fri, Jul 31, 2009 at 3:41 AM, < mazz(a)redhat.com > wrote:
It sounds like what you are doing is correct. If you have a plugin "A" and it has some classes that you want available to plugin "B", then plugin "B"'s descriptor should have a <depends> tag on plugin "A":
<plugin name="B" ...>
<depends plugin="A" useClasses="true" />
...
</plugin>
What this does is put A's plugin classloader as the parent to B's plugin classloader. You do not have to do anything else other than put that <depends> in your descriptor (no need to put the plugin jar in your plugin jar's lib directory).
FYI: The useClasses, if not defined, is inferred on the last <depends> tag listed in the descriptor. If you only have one <depends> tag, its useClasses is assumed true if its not specified.
BTW: recently, alot of work has gone into trunk that performs more classloading "stuff". See: http://jopr.org/confluence/display/RHQ/Plugin+Dependencies+and+Class+Loaders
----- Original Message -----
From: "Bruno Wassermann" < bruno.wassermann(a)googlemail.com >
To: "jopr-dev" < jopr-dev(a)lists.jboss.org >
Sent: Thursday, July 30, 2009 5:46:05 PM GMT -05:00 US/Canada Eastern
Subject: Re: [jopr-dev] Plugin Dependencies
Whoops, it should rather be <depends plugin="xyz" useClasses="true/>, right? Sorry about the premature question :(
-- Bruno
On Thu, Jul 30, 2009 at 10:41 PM, Bruno Wassermann < bruno.wassermann(a)googlemail.com > wrote:
Hi,
This may be a typical newbie question...
I want the Axis plugin to be able to reuse some classes defined in the Tomcat plugin, namely TomcatConfig. To achieve this lofty goal I add the following to Axis.rhq-plugin.xml: <depends plugin="Tomcat"/>.
However, at runtime the class loader for the Axis plugin doesn't seem to have loaded Tomcat's classes. Asking the agent to run a discovery scan, the Axis plugin reports a NoClassDefFoundError for org.jboss.on.tomcat.helper.TomcatConfig.
What am I getting wrong here? Do I have to manually add the Tomcat plugin's jar file to my plugin?
Many thanks,
-- Bruno
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14 years, 8 months
Re: [jopr-dev] Plugin Dependencies
by mazz＠redhat.com
It sounds like what you are doing is correct. If you have a plugin "A" and it has some classes that you want available to plugin "B", then plugin "B"'s descriptor should have a <depends> tag on plugin "A":
<plugin name="B" ...>
<depends plugin="A" useClasses="true" />
...
</plugin>
What this does is put A's plugin classloader as the parent to B's plugin classloader. You do not have to do anything else other than put that <depends> in your descriptor (no need to put the plugin jar in your plugin jar's lib directory).
FYI: The useClasses, if not defined, is inferred on the last <depends> tag listed in the descriptor. If you only have one <depends> tag, its useClasses is assumed true if its not specified.
BTW: recently, alot of work has gone into trunk that performs more classloading "stuff". See: http://jopr.org/confluence/display/RHQ/Plugin+Dependencies+and+Class+Loaders
----- Original Message -----
From: "Bruno Wassermann" <bruno.wassermann(a)googlemail.com>
To: "jopr-dev" <jopr-dev(a)lists.jboss.org>
Sent: Thursday, July 30, 2009 5:46:05 PM GMT -05:00 US/Canada Eastern
Subject: Re: [jopr-dev] Plugin Dependencies
Whoops, it should rather be <depends plugin="xyz" useClasses="true/>, right? Sorry about the premature question :(
-- Bruno
On Thu, Jul 30, 2009 at 10:41 PM, Bruno Wassermann < bruno.wassermann(a)googlemail.com > wrote:
Hi,
This may be a typical newbie question...
I want the Axis plugin to be able to reuse some classes defined in the Tomcat plugin, namely TomcatConfig. To achieve this lofty goal I add the following to Axis.rhq-plugin.xml: <depends plugin="Tomcat"/>.
However, at runtime the class loader for the Axis plugin doesn't seem to have loaded Tomcat's classes. Asking the agent to run a discovery scan, the Axis plugin reports a NoClassDefFoundError for org.jboss.on.tomcat.helper.TomcatConfig.
What am I getting wrong here? Do I have to manually add the Tomcat plugin's jar file to my plugin?
Many thanks,
-- Bruno
_______________________________________________
jopr-dev mailing list
jopr-dev(a)lists.jboss.org
https://lists.jboss.org/mailman/listinfo/jopr-dev
14 years, 9 months
Plugin Dependencies
by Bruno Wassermann
Hi,
This may be a typical newbie question...
I want the Axis plugin to be able to reuse some classes defined in the
Tomcat plugin, namely TomcatConfig. To achieve this lofty goal I add the
following to Axis.rhq-plugin.xml: <depends plugin="Tomcat"/>.
However, at runtime the class loader for the Axis plugin doesn't seem to
have loaded Tomcat's classes. Asking the agent to run a discovery scan, the
Axis plugin reports a NoClassDefFoundError for
org.jboss.on.tomcat.helper.TomcatConfig.
What am I getting wrong here? Do I have to manually add the Tomcat plugin's
jar file to my plugin?
Many thanks,
-- Bruno
14 years, 9 months
Fwd: Hudson Plugin
by John Mazzitelli
Opps... sent directly to Tiago, wanted to send to the list... reforwarding...
BTW: the JIRA in question is http://jira.rhq-project.org/browse/RHQ-2045
------------
Did you take a look at the hudson plugin prototype that is already in the RHQ SVN:
http://svn.rhq-project.org/repos/rhq/trunk/modules/plugins/hudson/
You can probably see how it did auto-discovery.
> "If JBoss AS Free Memory is running too low, invoke a Hudson operation such
> as 'kill all current builds' ". Does it sounds possible (and sensible) to you ?
This is a long desired feature not yet implemented (I'll see if I can dig out that JIRA). We need a way to have an alert triggered on one resource to execute an operation on another resource. That we do not have yet, so you can't do this today. BUT! What you could do is expose a "Free Memory" metric directly on your Hudson resource (you would need to collect that metric yourself in the Hudson component - but that's not difficult to do). That way, you have a metric AND the operation on the same resource, which would allow you to do what you want.
----- Original Message -----
From: "Tiago Bruno Pires Gomes" <tiago-bruno.piresgomes(a)atosorigin.com>
To: jopr-dev(a)lists.jboss.org
Cc: "romain pelisse" <romain.pelisse(a)atosorigin.com>
Sent: Wednesday, July 29, 2009 10:10:06 AM GMT -05:00 US/Canada Eastern
Subject: [jopr-dev] Hudson Plugin
Hi
I work on Hudson plugin for Jopr for several weeks now. I manage to some operations and metrics (not really usefull in this context) working. The plugin is still a beta but I feel it is working enough to be at release for review by jopr developer and contributor.
The plugin (and its history) is availaible on BitBucket, as a mercurial repository :
http://bitbucket.org/tpiresgo/hudsonplugin/
Also, I have some troubles understanding how auto discovery works, can someone help me with this ?
Once I'll get auto discovery working fine, I would like to know if such an operation sounds possible to you:
"If JBoss AS Free Memory is running too low, invoke a Hudson operation such as 'kill all current builds' ". Does it sounds possible (and sensible) to you ?
--
PIRES GOMES Tiago Bruno
Stagiaire Open Source Center
Open Source Center Trainee
_______________________________________________
jopr-dev mailing list
jopr-dev(a)lists.jboss.org
https://lists.jboss.org/mailman/listinfo/jopr-dev
14 years, 9 months
Hudson Plugin
by Tiago Bruno Pires Gomes
Hi
I work on Hudson plugin for Jopr for several weeks now. I manage to some operations and metrics (not really usefull in this context) working. The plugin is still a beta but I feel it is working enough to be at release for review by jopr developer and contributor.
The plugin (and its history) is availaible on BitBucket, as a mercurial repository :
http://bitbucket.org/tpiresgo/hudsonplugin/
Also, I have some troubles understanding how auto discovery works, can someone help me with this ?
Once I'll get auto discovery working fine, I would like to know if such an operation sounds possible to you:
"If JBoss AS Free Memory is running too low, invoke a Hudson operation such as 'kill all current builds' ". Does it sounds possible (and sensible) to you ?
--
PIRES GOMES Tiago Bruno
Stagiaire Open Source Center
Open Source Center Trainee
14 years, 9 months
AS5 integration tests annotations
by Lukas Krejci
Hi all,
I just commited (r995) changes to the AS5 plugin integration tests that I hope
will bring a bit more clarity to the way we set up the tests.
First of all, the AbstractResourceTest doesn't define any @Test methods
anymore. The methods are kept in the class but made protected. This makes it
possible for the actual tests inheriting from this class to decide what tests
will be called by inheriting those methods and making them public.
Secondly, the @Test annotations are only defined on class level on the concrete
test classes. All the tests belong to "as5-plugin" group. This enables us to
disable them in the pom.xml with a single command. If you need to do some
setup, you can either create a @BeforeTest method (but beware that this method
will be run before any @BeforeGroups methods) or in case you have a setup
method common to more test classes you can do it like this:
class SetupClass {
@BeforeGroups(groups = "my-group")
public void setup() {}
}
@Test(groups = {"as5-plugin", "my-group"})
class Test {
public void test() {}
}
In a more complicated use case for EJB2 tests the following is done:
abstract class AbstractEjb2Test {
@BeforeGroups(groups = "as5-plugin-ejb2")
public void deployJars() {}
}
@Test(groups = {"as5-plugin", "as5-plugin-ejb2", ...})
class Ejb2SLSBTest extends AbstractEjb2Test {
@BeforeGroups(groups = "as5-plugin-ejb2", dependsOnMethods = "deployJars")
public void setup() {}
... test methods ...
}
This way we can have 1 abstract parent class that deploys all the necessary
jars and a number of child classes, each with its own setup methods that will
be called only after the jars are deployed.
The EjbSLSBTest.setup() method needs to be annotated as @BeforeGroups, not as
@BeforeTest, because the @BeforeTest method would be called before all the
@BeforeGroups (and it is not possible to declare it dependent on the
deployJars method due to the way TestNG works).
Hope this makes sense,
Lukas
14 years, 9 months
Introduction and first question
by Bruno Wassermann
Hi,
I am interested in some slight modifications to Jopr and RHQ that I am going
to try my luck with over the next couple of weeks. In particular, I want to
introduce dependencies between components (on a single host, between
components on differents in the same domain and inter-domain) that can be
displayed to users. I am also interested in plugins for SOAP runtimes, such
as Axis, the ActiveBPEL engine and some Grid middleware, all of which I will
hopefully be able to contribute.
My first question is to do with the new Tomcat plugin. Discovery of Tomcat
works, but the plugin mistakenly insists that the Tomcat instance is not
available. I found that its EMSConnection is not servicing any requests,
which results in a corresponding exception and the connection to be closed.
Hence, the plugin does not successfully collect any metrics I would like it
to.
JConsole on the same host works fine and allows me to inspect all the
MBeans.
Does anyone have any ideas why the the Tomcat plugin's connection is not
responsive (using the same URL as for JConsole)?
Thanks,
-- Bruno
14 years, 9 months
classloader branches are merged
by John Mazzitelli
Its too bad I don't start my Disney vacation tomorrow, because boy do I have some checkins for that :) At least I did it on a Friday night, so I got that going for me.
RHQ-2059 has been implemented and the classloading branches (RHQ and Jopr) have been merged into trunk.
I ran tests on Jopr AND Embedded Jopr - everything works, no errors in logs.
I recommend everyone do a clean rebuild of their container, lots of changes and you need to pick up EMS 1.2.11 so its best to do a clean build just to make sure you don't have any lingering old code.
What we can do now is continue to perform some profiling to make sure we keep trying to make this stuff more efficient.
14 years, 9 months
new classloading and emb jopr
by mazz＠redhat.com
Good news on the new classloading stuff and embedded jopr. Profiling data looks good. Branch even performed slightly better than trunk, but for all intents and purposes, let's call it a wash.
See attached. The snapshots you really want to compare are #3 and #6 on the graphs (those were taken after I was clicking around the admin console a bit)
14 years, 9 months
