Re: [gpsd-users] Control Gpsd

[bruno suarez]

Another solution without programming is to use watchdog and monitoring 
the pid file of gpsd

This works for me, if gpsd stops the system reboot

Bruno

Le 15/03/2016 18:01, bruno suarez a écrit :
> Thanks for the help.
> This is a good start for me ...
> I'll try this, I think in the script (cron) I will restart Pi directly 
> because if there is a problem it may be the receiver or other items
>
> Bruno
>
> Le 15/03/2016 17:01, Alexander Carver a écrit :
> > I can't really give you an example because there's many ways of doing
> > it.  It's all up to the programming languages you are most familiar with
> > (and those that run on the Raspberry Pi).  It's also not exactly a one
> > or two line script although there are some very rough ways of doing it
> > in a small script, they're not very robust.
> >
> > But in general you need to write a small program that connects to gpsd,
> > sends the WATCH command so that data streams from the attached GPS
> > receiver and then detect if that data stops flowing (because gpsd
> > crashed) or the data isn't updating (because the GPS receiver failed or
> > disconnected).  In that case you send a system call to kill the PID of
> > the gpsd process then start a new copy.
> >
> >
> > The small script version would be something like (this is completely
> > untested, don't use it)
> >
> > #!/bin/bash
> > GPSDPID=$(ps ax | grep gpsd | grep -v grep | awk '{print $1}')
> > GPSDSTATE=$(ps ax | grep gpsd | grep -v grep | awk '{print $3}'
> > GPSDCMD="/path/to/gpsd --with-parameters"
> > if [ "$GPSDSTATE" == 'Z' ] || [ -z "$GPSDPID" ];
> > then
> >     echo 'gpsd is a zombie or it's completely missing, kill it'
> >     if [ -n "$GPSDPID" ];
> >     then
> >         kill -KILL $GPSDPID
> >         sleep 1
> >     fi
> >
> >     $GPSDCMD
> > fi
> >
> > Basically that script would look at the process list to see if gpsd was
> > there, pull out the PID and the state and then see if the state is a Z
> > (zombie process) or an empty string (the -z) in which case it died and
> > needs to be restarted.  This is a bad script because it can't catch many
> > problems that might leave gpsd running but not really functioning.
> >
> > You are better off using something else to connect directly to gpsd's
> > TCP port and taking action if the data isn't there, the port closes or
> > some other detail you don't like.
> >
> >
> > On 2016-03-14 23:51, bruno suarez wrote:
> > > Hello,
> > >
> > > Thank you for the reply and the idea of chemical heat packs.
> > > The watchdog is expected.
> > >
> > > On monitoring GPSD, ok for the principle, but a sample script would 
> > > help
> > > me (I am not a man of script!).
> > >
> > >
> > > Thank you for your answers and tips
> > > cordially
> > > Bruno
> > >
> > > Le 15/03/2016 07:36, Alexander Carver a écrit :
> > > > On 2016-03-14 12:06, bruno suarez wrote:
> > > > > Hello,
> > > > > For a stratospheric balloon project, I usea raspberry Rasbian 
> > > > > Jessie and
> > > > > a USB GPS receiver.
> > > > >
> > > > > Everything is OK with gpsd and my GPS receiver.
> > > > > When I plug everything works correctly, gpsd start on the correct 
> > > > > port
> > > > > /dev/ttyUSB0.
> > > > >
> > > > > However, I want to make sure that everything works properly during 
> > > > > 2/3
> > > > > hours to extremely cold temperature
> > > > >
> > > > > What is the easiest way to automatically control the operation of 
> > > > > GPSD
> > > > > and relaunch it(on the same port detected ) if it is stopped or if 
> > > > > it is
> > > > > in error.
> > > > >
> > > > > Thank you for your answers and tips
> > > > >
> > > > > Cordially
> > > > > Bruno
> > > > First, pack your payload with heaters.  You can use chemical heat 
> > > > packs
> > > > from a pharmacy that are normally used for heating muscles and joints
> > > > (these are the plastic bags that you smash to mix the chemicals and 
> > > > they
> > > > get warm.)  In an insulated container you should stay within your
> > > > operating limits of the Pi (the lower limit is approximately -20
> > > > Celsius).
> > > >
> > > > After that, just set up a script that watches for data coming from 
> > > > gpsd
> > > > and, if there is no data, issue a kill for the PID of gpsd and restart
> > > > it.  Since gpsd can support more than one connection you can get data
> > > > for your recording/telemetry program and have a completely separate
> > > > program running to watch for a loss of communication.
> > > >
> > > > Also make sure to enable the watchdog timer in the Pi so that it will
> > > > reboot if the whole system fails.  Make sure gpsd will start at 
> > > > boot as
> > > > well as your data logging/telemetry program and the monitoring script.