Dan Stromberg wrote:

> I'm writing an application launcher. It spawns GUI commands on remote
> hosts via ssh tunnels, potentially behind multiple firewalls, and perhaps
> other forms of tunnels later.
>
> I want to provide some sort of feedback to the user as to whether the
> window started up OK.
>
> My application is in PyGTK2 (and will be GPL'd) but I'm spawning generic X
> apps, including apps based on Gnome, KDE, Motif, Athena, and so on.
>
> Is there something in X I can query to see if these apps are being added
> to the display?

X isn't going to be of much help here. There's no reliable way to
determine whether some application has come up successfully by looking
at the display. You might see an error window come up and then go away
and interpret it as success.

If the application fails to come up and exits with non-zero you should
report that as a problem and any output on stderr. But some
applications may have non-X errors and pop up an error dialog then wait
for a response. Such an app would look happy to you until someone
dismisses the dialog.

The best you can do at the X level is provide passive dynamic feedback
about what is going on on the server side and let the user interpret
it. The feedback I'd suggest would include a perfmeter to show CPU
status and an event log of application level windows/titles coming and
going on the remote display. The latter could be just a diff of the
output of xlsclients over time. So if I launch say an xterm I should
see the CPU go busy and then one or more messages indicating that a new
xterm came up.

-- ced

>
> I'd be willing to add a little C program to do the querying, if need be,
> though I'd prefer to stay with pure python if possible.
>
> Ideal might be if I could feed a random, longish cookie to an application
> upon startup, and then query the X server to see if there is an
> application that has that cookie-attribute.
>
> Barring that, I see some semi-useful stuff in "xwininfo -root -tree", but
> I'd prefer not to have to ask the enduser for the magic strings to search
> for in that, if possible.
>
> Any suggestions?
>
> Thanks!
>
>
>


--
Chuck Dillon
Senior Software Engineer
NimbleGen Systems Inc.

Dan Stromberg wrote:
>
>I'm writing an application launcher. It spawns GUI commands on remote
>hosts via ssh tunnels, potentially behind multiple firewalls, and perhaps
>other forms of tunnels later.
>
>I want to provide some sort of feedback to the user as to whether the
>window started up OK.
>
>My application is in PyGTK2 (and will be GPL'd) but I'm spawning generic X
>apps, including apps based on Gnome, KDE, Motif, Athena, and so on.
>
>Is there something in X I can query to see if these apps are being added
>to the display?
>
>I'd be willing to add a little C program to do the querying, if need be,
>though I'd prefer to stay with pure python if possible.
>
>Ideal might be if I could feed a random, longish cookie to an application
>upon startup, and then query the X server to see if there is an
>application that has that cookie-attribute.
>
>Barring that, I see some semi-useful stuff in "xwininfo -root -tree", but
>I'd prefer not to have to ask the enduser for the magic strings to search
>for in that, if possible.
>
>Any suggestions?
>
>Thanks!

For the sake of using the correct terminology, what you are doing is
called Session Management. So, either you are trying to extend the
functionality of an existing session manager, or you are trying to
roll your own -- I can't really discern which.

Historically, X has had xsm as a session manager, and xsm uses the
XSMP protocol. A compliant application has the responsibility of
supplying certain information for session management: most do, but
those that don't will, of course, be a problem.

A full-function client initiates a connection with the session manager
in order to provide information, and in order to respond to certain
events (such as session shutdown). Such a client historically would
do so by using the Xt session management functionality.

It is also possible to write a minimal-function client, and in fact,
this is very common. These clients do not have to connect to the
session manager -- what happens is that their presence is detected by
a "session manager proxy" that notices their launches and communicates
with the session manager for them. For this to work, the clients must
provide a minimal set of properties on their top-level windows.

What you are trying to do is has to fit this framework in some
fashion. There are many possible designs, but the simplest is
probably something like emulating a session manager proxy to some
degree. That is, you monitor top-level window creation; you monitor
property events on such windows; you interpret the creation of session
management properties as confirmation that the window has been
launched.

You probably should start by looking at the session management
sections of the ICCCM.

Dan Stromberg writes:

> I want to provide some sort of feedback to the user as to whether the
> window started up OK.
>
> My application is in PyGTK2 (and will be GPL'd) but I'm spawning generic X
> apps, including apps based on Gnome, KDE, Motif, Athena, and so on.

I believe a "startup notification" protocol has been designed for
this, and GNOME now uses it. But I don't know how well it works
with clients that don't explicitly support it.

http://www.freedesktop.org/wiki/Soft...2dnotification
http://www.freedesktop.org/wiki/Stan...ication_2dspec
http://www.freedesktop.org/software/...tion/releases/