OF on raspberry PI 4 with buster, how to restart crashed app?

#1

I have successfully managed to get my OF app to auto start once the RPI desktop is done starting.
To make this happen I had to:

sudo nano /etc/xdg/lxsession/LXDE-pi/autostart

then add this line to the file

@sudo /home/pi/openFrameworks/apps/folderName1/folderName2/bin/myApp

Now I was hoping to find a way to use systemd to tread the app as a service and start it when it is not running. Maybe it’s a bad idea to run it as a service and there might be a completely different way to achieve this. ?

I tried following these steps:
https://slippytrumpet.io/posts/running-your-app-as-service-on-pi-zero-w/
and these:


Also this video was helpful:

But it still does not work.
Here my print out after calling sudo service myProg status

● myProg.service - my service
   Loaded: loaded (/etc/systemd/system/myProg.service; disabled; vendor preset: enabled)
   Active: failed (Result: signal) since Wed 2020-01-22 15:06:10 EST; 6s ago
  Process: 1079 ExecStart=/usr/bin/sudo /home/pi/openFrameworks/apps/remotePulse/remotePulse/bin/remotePulse (code=k
 Main PID: 1079 (code=killed, signal=SEGV)

Jan 22 15:06:10 raspberrypi systemd[1]: Started my service.
Jan 22 15:06:10 raspberrypi sudo[1079]:     root : TTY=unknown ; PWD=/home/pi/openFrameworks/apps/remotePulse/remote
Jan 22 15:06:10 raspberrypi sudo[1079]: pam_unix(sudo:session): session opened for user root by (uid=0)
Jan 22 15:06:10 raspberrypi sudo[1079]: [ error ] ofAppGLFWWindow: 65544: X11: The DISPLAY environment variable is m
Jan 22 15:06:10 raspberrypi sudo[1079]: [ error ] ofAppGLFWWindow: couldn't init GLFW
Jan 22 15:06:10 raspberrypi sudo[1079]: [ error ] ofAppGLFWWindow: 65537: The GLFW library is not initialized
Jan 22 15:06:10 raspberrypi sudo[1079]: pam_unix(sudo:session): session closed for user root
Jan 22 15:06:10 raspberrypi systemd[1]: myProg.service: Main process exited, code=killed, status=11/SEGV
Jan 22 15:06:10 raspberrypi systemd[1]: myProg.service: Failed with result 'signal'.

Here my myProg.service file:

[Unit]
Description=my service
After=network.target

[Service]
User=root
WorkingDirectory=/home/pi/openFrameworks/apps/remotePulse/remotePulse/bin
ExecStart=sudo /home/pi/openFrameworks/apps/remotePulse/remotePulse/bin/remoteP$

[Install]
WantedBy=multi-user.target
#2

You’ll probably be able to do it with Linux scripting, which I can’t help much with, but is ofxWatchdog (https://github.com/toolbits/ofxWatchdog) an option?

#3

Hi,
I’ve recently used systemd to start some SuperCollider programs and had accidentally set Restart=always, which at least always restarted SC when I killed it with kill -9 PID.
Maybe you could try to start the app with systemd, instead of the autostart file?
I simply followed the Raspberry Pi instructions for systemd.
Oh, and is the [ error ] ofAppGLFWWindow: 65544: X11: The DISPLAY environment variable is missing a problem? In that case: that reminds me of starting GUI applications from SSH, to run on the remote machine.
Maybe you need to call

export DISPLAY=:0 
xhost+

That’s at least what I do when I want to start OF-apps on my Ubuntu setup.

#4

thanks for the pointers.
@Jildert I am a bit new to this. so I do not know where to put the export DISPLAY=:0 ? in to the .service ?
thanks a bunch

#5

Now I think of it, I haven’t used that for my SC startup :sweat_smile:
Anyway, I called a .sh script from systemd, although I think putting everything in one line will do the job as well.
ExecStart=sudo export DISPLAY=:1; xhost+; sudo /home/pi/openFrameworks/apps/remotePulse/remotePulse/bin/remoteP$
Not sure if this will work.

I had some problems with the unavailable X session (same kind of errors with the DISPLAY variable), which I didn’t need anyway, but SC needed it to start.
So I used a fake X server (Xvfb) to connect to (since I didn’t use a monitor)
But for your case:
I assume the Raspberry boots into autologin desktop mode? So then the X server should be available…
I think the service may be called too soon? This may work (setting the service to idle)?
Can’t test right now, so I apologize if my suggestions may lead to confusion.

Edit: (now I see you’re errors are already in sudo service myProg status…)
Edit:
Starting services from user session (StackOverflow)

#6

Thanks again.
I will try this now.

But I will also add some more findings here for my future self.

I already have this watchdog.sh that I use on my macOS machines. It checks a log file and if this log file was not updated in the last n seconds it tries to start my OF app.

I modified it a bit and it now also runs a PI. But only if I call it through the terminal direclty. All of these 3 ways to call it work.

/home/pi/Desktop/watchdog.sh
bash  /home/pi/Desktop/watchdog.sh
sudo bash  /home/pi/Desktop/watchdog.sh

So I thought I can could trigger this watchdog.sh via crontab. BUT the script does not run when using crontab.
I tried all of the following.

* * * * * bash /home/pi/Desktop/watchdog.sh
* * * * * sudo bash /home/pi/Desktop/watchdog.sh
* * * * * bash -x /home/pi/Desktop/watchdog.sh > /home/pi/Desktop/clog.log
* * * * * sudo bash -x /home/pi/Desktop/watchdog.sh > /home/pi/Desktop/clog.log

the log file does echo prints the .sh script but never opens the OF this way.

#7

no success yet.

this is what my .service file looks like. which lives in /etc/systemd/system/hemmer.service

[Unit]
Description=hemmer
After=network.target

[Service]
ExecStart=sudo export DISPLAY=:1; xhost+; sudo /home/pi/openFrameworks/apps/remotePulse/remotePulse/bin/remotePulse
WorkingDirectory=/home/pi/openFrameworks/apps/remotePulse/remotePulse/bin
StandardOutput=inherit
StandardError=inherit
StartLimitInterval=5min
Restart=always
User=root

[Install]
WantedBy=multi-user.target

when calling:

pi@raspberrypi:/etc/systemd/system $ sudo systemctl status hemmer.service

this gets printed:

● hemmer.service - hemmer
   Loaded: loaded (/etc/systemd/system/hemmer.service; enabled; vendor preset: enabled)
   Active: failed (Result: exit-code) since Thu 2020-01-23 10:01:54 EST; 936ms ago
  Process: 1205 ExecStart=/usr/bin/sudo export DISPLAY=:1; xhost+; sudo /home/pi/openFrameworks/apps/remotePulse/remo
 Main PID: 1205 (code=exited, status=1/FAILURE)

Jan 23 10:01:54 raspberrypi systemd[1]: hemmer.service: Service RestartSec=100ms expired, scheduling restart.
Jan 23 10:01:54 raspberrypi systemd[1]: hemmer.service: Scheduled restart job, restart counter is at 5.
Jan 23 10:01:54 raspberrypi systemd[1]: Stopped hemmer.
Jan 23 10:01:54 raspberrypi systemd[1]: hemmer.service: Start request repeated too quickly.
Jan 23 10:01:54 raspberrypi systemd[1]: hemmer.service: Failed with result 'exit-code'.
Jan 23 10:01:54 raspberrypi systemd[1]: Failed to start hemmer.

I tried DISPLAY=:1 and DISPLAY=:0

#8

have not yet found the magic mix to make it work with systemd.

But using crontab which calls my custom .sh script works now.

sudo crontab -e
then past in this line:
* * * * * bash /home/pi/Desktop/startMyApp.sh

a very simple startMyApp.sh script to start my OF app. Be careful crontab will open this app every minute. So, this is just for quick testing.

#!/bin/bash
export XAUTHORITY=/home/pi/.Xauthority
export DISPLAY=:0.0
echo "testing my script"

sleep 1
sudo /home/pi/openFrameworks/apps/remotePulse/remotePulse/bin/remotePulse &
echo "should have started app"