Re: [yocto-autobuilder][PATCH] cleanup and restart crashed vnc server

[Joshua Lock <joshua.g.lock@linux.intel.com>]

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On Wed, 2016-08-17 at 17:12 +0100, Joshua G Lock wrote:
> On Wed, 2016-08-17 at 16:09 +0000, Randle, William C wrote:
> > On Wed, 2016-08-17 at 16:59 +0100, Joshua G Lock wrote:
> > 
> > > On Tue, 2016-08-16 at 17:09 -0700, Bill Randle wrote:
> > > > > > > > Use a common script to check for a running vnc server, and if
not
> > > > running
> > > > cleanup dangling lock files and restart the server.
> > > > 
> > > > [YOCTO #8210]
> > > > 
> > > > > > > > Signed-off-by: Bill Randle <william.c.randle@intel.com>
> > > > ---
> > > > > > > >  bin/checkvnc                                                  
 | 10
> > > > ++++++++++
> > > > > > > >  .../site-packages/autobuilder/buildsteps/RunESDKSanityTests.py 
|  3
> > > > +--
> > > > > > > >  .../site-
packages/autobuilder/buildsteps/RunOeSelftest.py      |  3
> > > > +--
> > > > > > > >  .../site-
packages/autobuilder/buildsteps/RunSDKSanityTests.py  |  3
> > > > +--
> > > > > > > >  .../site-
packages/autobuilder/buildsteps/RunSanityTests.py     |  3
> > > > +--
> > > >  5 files changed, 14 insertions(+), 8 deletions(-)
> > > >  create mode 100755 bin/checkvnc
> > > > 
> > > > diff --git a/bin/checkvnc b/bin/checkvnc
> > > > new file mode 100755
> > > > index 0000000..574ba48
> > > > --- /dev/null
> > > > +++ b/bin/checkvnc
> > > > @@ -0,0 +1,10 @@
> > > > +#!/bin/sh
> > > > +#
> > > > > > > > +# check if vnc server is running, and if not, cleanup and
restart
> > > > +#
> > > > +pid=$(pidof Xvnc)
> > > > +if [[ $? != 0 ]]; then
> > > > +    echo "Xvnc not running, attempting restart"
> > > > +    vncserver -kill :1
> > > > +    vncserver
> > > 
> > > > > > The vncserver is currently started with `vncserver :1`, whereas
this
> > > script just calls `vncserver` — is that intentional/desirable?
> > > 
> > > > > > Would it be a little cleaner/more robust if we didn't assume only
one
> > > > > > Xvnc instance was running and instead write the pid of the
process we
> > > start to a file and use that file to check the status?
> > > 
> > > Regards,
> > > 
> > > Joshua
> > > 
> > > 
> > 
> > 
> > 
> > 
> > > > The vncserver program is a shell script and uses :1 as the default
display.
> > 
> > 
> > 
> > 
> > 
> > > > > > > > The pid of Xvnc is written to a file already. The problem is, if
Xvmc crashes, the pid file (and lock file) are left around, so just
looking at the pid file existance, you can't tell if it's actually
running or not.
> > 
> 
> 
> > > > Can we read the pid from the pidfile and do the tidy up if the
process isn't running? My main concern here is that we assume only a
single instance of Xvnc is running, I'm not sure if that is a safe
assumption to make?

It turns out we implicitly assume only one vncserver is running (on
display 1) in several places throughout the AB codebase. Therefore I've
pushed this change to master.

Thanks,

Joshua

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