8:11 p.m.
Hi George,
thanks for your feedback. Please find my answers below.
1) Are the plugins hosted by the same jboss server that hosts the
engine? It would appear the answer is yes and that no separate container is required for
the plugins.
In short, yes.
Plugins, along with their configuration and 3rd party dependencies, are meant to be
embedded into final WebAdmin HTML page, see
[http://www.ovirt.org/wiki/Features/UIPlugins#Plugin_lifecycle] step #5.
JBoss AS instance serves WebAdmin HTML page (WebadminDynamicHostingServlet), along with
providing GWT RPC and REST endpoints that delegate to Engine business logic through EJB
BackendLocal interface.
However, plugins are not 'hosted' in a typical sense -
WebadminDynamicHostingServlet reads and embeds all plugin data directly into final
WebAdmin HTML page.
2) Does each plugin map to a unique extension within WebAdmin? Your
example shows that I can extend the VM table to have a "Show VM name and edit
VM" context-sensitive extension. This is named pluginApi.plugins.myPlugin. Can I
safely assume that this is per extension? I would have pluginApi.plugins.myPlugin2 for
extending a storage domain?
Extension points are represented by application events, triggered by WebAdmin and consumed
by plugins. For example, 'tableContextMenu' event gets triggered when a table
context menu is about to be shown to the user, which gives plugins the ability to do
something custom with the context menu before it's shown.
There can be multiple plugins handling the same event (extension point). You can have two
plugins, say 'pluginApi.plugins.One' and 'pluginApi.plugins.Two', each
providing 'tableContextMenu' function for handling the above mentioned event.
WebAdmin will invoke all plugins for the given event.
To answer your question, in order to handle X events (extension points), you don't
need to write X plugins. You can write one plugin that handles X events.
3) Instead of launching a jQuery dialog, can I point to a compiled
GWT html file to display a dialog that fits my needs?
You can do anything you want in your plugin event handler function. Show a jQuery UI
dialog, make oVirt REST API request, call arbitrary remote server using cross-domain
technique like JSONP [1] or CORS [2], etc. Plugin authors are free to decide if they want
to rely on 3rd party JavaScript libraries, or if they want to write entire plugin code by
themselves.
In my opinion, tools like jQuery are far more elegant for handling simple things such as
UI dialogs. But if you really want to use GWT for this purpose, I suggest following
approach:
a, develop a 'plugin support application' in GWT, which implements the necessary
dialog functionality
b, export its main (e.g. dialog handling) classes for use in native JavaScript through
gwt-exporter [3]
c, have your oVirt UI plugin depend on your compiled 'plugin support application'
(this will cause your 'plugin support application' to be called during WebAdmin
startup)
d, in your oVirt UI plugin, invoke 'plugin support application' functionality
through exported classes (plugin -> GWT delegate pattern)
4) Is session info passed into the plugin so that I can invoke APIs
into the engine? To power on a VM for instance? Or to mount a new NFS storage domain?
Yes, this should be part of
[http://www.ovirt.org/wiki/Features/UIPlugins#Global_API_functions] "Plugin utility
functions" (global API).
Your plugin might access user session information in the following way:
pluginApi.util().userInfo().* (replace * with id(), name(), domain(), etc.)
As you pointed out, this could be used to authenticate oVirt REST API requests made from
your plugin code.
BTW, the link to the original design notes on the wiki doesn't
work.
This is strange, [http://rhevmf.pad.engineering.redhat.com/68] has its visibility set to
"Public (Allow Internet guests)" ... Does anybody know why this doesn't
work?
Vojtech
[1] http://en.wikipedia.org/wiki/JSONP
[2] http://en.wikipedia.org/wiki/Cross-origin_resource_sharing
[3] http://code.google.com/p/gwt-exporter/
----- Original Message -----
From: "George Costea" <George.Costea(a)netapp.com>
To: "Vojtech Szocs" <vszocs(a)redhat.com>, engine-devel(a)ovirt.org
Cc: "Dustin Schoenbrun" <Dustin.Schoenbrun(a)netapp.com>, "Ricky
Hopper" <Ricky.Hopper(a)netapp.com>
Sent: Monday, June 25, 2012 3:09:43 PM
Subject: RE: oVirt UI Plugins feature: Ready for review
Hi Vojtech,
I have a few questions on this feature.
1) Are the plugins hosted by the same jboss server that hosts the engine? It would appear
the answer is yes and that no separate container is required for the plugins.
2) Does each plugin map to a unique extension within WebAdmin? Your example shows that I
can extend the VM table to have a "Show VM name and edit VM" context-sensitive
extension. This is named pluginApi.plugins.myPlugin. Can I safely assume that this is
per extension? I would have pluginApi.plugins.myPlugin2 for extending a storage domain?
3) Instead of launching a jQuery dialog, can I point to a compiled GWT html file to
display a dialog that fits my needs?
4) Is session info passed into the plugin so that I can invoke APIs into the engine? To
power on a VM for instance? Or to mount a new NFS storage domain?
BTW, the link to the original design notes on the wiki doesn't work.
Thanks,
George
-----Original Message-----
From: Vojtech Szocs [mailto:vszocs@redhat.com]
Sent: Thursday, June 21, 2012 11:03 AM
To: engine-devel(a)ovirt.org
Cc: Schoenbrun, Dustin; Costea, George; Hopper, Ricky
Subject: oVirt UI Plugins feature: Ready for review
Hi guys,
I wrote a wiki page describing UI Plugins, a feature planned for oVirt web administration
(WebAdmin) application:
http://www.ovirt.org/wiki/Features/UIPlugins
Feature design is finished and ready for review. Please feel free to add comments, ask
questions or reach me directly on #ovirt channel.
Cheers,
Vojtech