Python Forum
Issues with Python script as service - Printable Version

+- Python Forum (https://python-forum.io)
+-- Forum: Python Coding (https://python-forum.io/forum-7.html)
+--- Forum: General Coding Help (https://python-forum.io/forum-8.html)
+--- Thread: Issues with Python script as service (/thread-11052.html)



Issues with Python script as service - satishgunjal - Jun-20-2018

Setup details:
RPI Version: Raspberry Pi 2 Model BV1.1
Python Version: 2.7

I have created a small program to control the fan and lights in my hydroponic room. I am using 8 channel relay board with external power supply. Everything works fine if I run script using below command
‘sudo python /home/pi/lionsfort/hydroponic.py’. To stop the execution I type CTRL+C then script stops properly with relay getting power off.

Since I wanted script to start with Raspberry pi, I am running ‘hydroponic.py’ script as a service. But with script running as service created below problems
1. Only console logs getting written and file logs are empty.
2. Script starts ok with relay functioning properly, but when I stop the service (sudo systemctl stop hydroponic.service) relay wont get power off.
3. Script start with raspberry pi power on but also start with every new PUTTY session. There should be only one instance of script running irrespective PUTTY session.

Note: If run script using ‘sudo python /home/pi/lionsfort/hydroponic.py’ I don’t face any of above problems!!

Followed below process to run script as a service on boot: (ref http://www.diegoacuna.me/how-to-run-a-script-as-a-service-in-raspberry-pi-raspbian-jessie/)
1. cd /lib/systemd/system/
2. sudo nano hydroponic.service
3. hydroponic.service content
[Unit]
Description=Hydroponic
After=multi-user.target

[Service]
Type=simple
ExecStart=/usr/bin/python /home/pi/lionsfort/hydroponic.py
Restart=on-abort

[Install]
WantedBy=multi-user.target

4. To activate it, I ran below commands
a. sudo chmod 644 /lib/systemd/system/ hydroponic.service
b. chmod +x /home/pi/lionsfort/hydroponic.py
c. sudo systemctl daemon-reload
d. sudo systemctl enable hydroponic.service
e. sudo systemctl start hydroponic.service

logging.json

--
Satish Gunjal


RE: Issues with Python script as service - gontajones - Jun-20-2018

Systemd logs into syslog, try to run:

sudo journalctl -u hydroponic
Also check the /var/log folder, maybe the stdout of your service is writing in the /var/log/message file.

About file logs, use the full path when writing them.
/home/pi/lionsfort/hydroponic.log



RE: Issues with Python script as service - satishgunjal - Jun-20-2018

@gontajones Logs issue resolved after giving the full path of the log file. Thanks! Also please help me on issue 2: command " sudo systemctl stop hydroponic.service" stops service but relays are still power on!


RE: Issues with Python script as service - gontajones - Jun-20-2018

Good, you're welcome!

About the "systemctl stop" command, it sends a SIGTERM to the service.
You'll have to get this signal (try: except:), reset the relays (clear GPIOs) and then exit.

Maybe your code now is just exiting.


RE: Issues with Python script as service - satishgunjal - Jun-20-2018

Code snippet as below. Please suggest where to make change?

try:
    initialize()
    while True:	
        hourMinute = datetime.now().strftime('%H:%M')
        logger.info("Main()> hourMinute= " + hourMinute)
	
	humidityAndTemp();
	
        if(iState == 'off'):
            startInletFan(hourMinute)
        else:
            stopInletFan(hourMinute)            
        
	if(eState == 'off'):
            startExhaustFan(hourMinute)
        else:
            stopExhaustFan(hourMinute)
        
	if(vState == 'off'):
            startVentilationFan(hourMinute)
        else:
            stopVentilationFan(hourMinute)

	if(pState == 'off'):
            startPump(hourMinute)
        else:
            stopPump(hourMinute)
	
	time.sleep(30)

# End program cleanly with keyboard
except KeyboardInterrupt:
    print " Quit"

# Reset GPIO settings
GPIO.cleanup()



RE: Issues with Python script as service - gontajones - Jun-20-2018

Could you edit your post (code) using the python tags?
Just click on "Insert python" at text formatting bar when editing (writing) posts.


RE: Issues with Python script as service - satishgunjal - Jun-20-2018

done.


RE: Issues with Python script as service - gontajones - Jun-20-2018

import time
import signal
import sys

def handler(signum, frame):
    print 'Got SIGTERM!'
    sys.exit(0) # raises a SystemExit exception

# Register a handler (function) for the SIGTERM signal
signal.signal(signal.SIGTERM, handler)

try:
    initialize()
    while True:
        hourMinute = datetime.now().strftime('%H:%M')
        logger.info("Main()> hourMinute= " + hourMinute)

        humidityAndTemp();

        if(iState == 'off'):
            startInletFan(hourMinute)
        else:
            stopInletFan(hourMinute)

        if(eState == 'off'):
            startExhaustFan(hourMinute)
        else:
            stopExhaustFan(hourMinute)

        if(vState == 'off'):
            startVentilationFan(hourMinute)
        else:
            stopVentilationFan(hourMinute)

        if(pState == 'off'):
            startPump(hourMinute)
        else:
            stopPump(hourMinute)

        time.sleep(30)

# End program cleanly with keyboard or sys.exit(0)
except KeyboardInterrupt:
    print " Quit (Ctrl+C)"
except SystemExit:
    print " Quit (SIGTERM)"

# Reset GPIO settings
GPIO.cleanup()



RE: Issues with Python script as service - satishgunjal - Jun-21-2018

thanks. all issues resolved!