Python Script Spawned by Cron or Systemd doesn't write files..?

[johnnyrobot]

Hi all,

I've written a Raspberry Pi application (Ubuntu Mate) that's essentially a timed camera. Every 30 seconds, it snaps an image and writes it to disk.

When I start the application manually from the terminal, it works as expected.

When I configure the script to execute automatically at startup, (using crontab or systemd - It needs to be executed as root) the script runs without any error, but no images are written to the disk.

Any idea of what may be going on?

My script:

import time from camera import * import cv2 count = 0 while True: # Open camera Camera01.GiGe.Open() # Turn on Light Camera01.Light.fill((255, 255, 255, 255)) # Snap Image image = Camera01.GiGe.GrabOne(1000) # Convert image to OpenCV Array image = cv2.cvtColor(image.Array, cv2.COLOR_BAYER_BG2BGR) # Save image to disk cv2.imwrite('saved_images/image'+str(count)+'.png', image) # Turn off Light Camera01.Light.fill((0, 0, 0, 0)) # Close camera Camera01.GiGe.Close() # Increment counter count = count + 1 time.sleep(30)

The camera class:

import neopixel import board from pypylon import pylon class Camera01: GiGe = pylon.InstantCamera(pylon.TlFactory.GetInstance().CreateFirstDevice()) Light = neopixel.NeoPixel(board.D18, 16, bpp=4, auto_write=True)

My crontab:
@reboot python3 /var/www/camera/main.py > /var/log/cron/crontab.log 2>&1

[johnnyrobot]

I figured it out, I never specified a working directory. When I setup the application as a service, there is a "WorkingDirectory" assignment that I was missing. Once specified, it's working as it should.

[Unit] Description=Time lapse camera application [Service] WorkingDirectory=/var/www/camera/ User=root ExecStart=/usr/bin/python3 /var/www/camera/main.py Restart=always [Install] WantedBy=multi-user.target

[Larz60+]

Please mark as solved (this helps moderators when scanning so many queries)
Thanks