autorun picamera script in rc.local doesnt actually record video

Question

I have the following code which I can run normally to record video, using python3 button_led_video.py, however when I put it into /etc/rc.local the camera no longer records video. Here is the python3 script:

#!/usr/bin/python3

from gpiozero import Button
from gpiozero import LED
from picamera import PiCamera
from datetime import datetime
from time import sleep

# setup camera and button
camera = PiCamera()
button = Button(4)
led = LED(17)

# recording flag
is_recording = 0

try:
    # calibrate the camera
    camera.start_preview()
    print("CALIBRATING...")
    sleep(2)
    print("READY TO RECORD!")
    print()

    while True:
        if (button.value == True) and (is_recording == 0):
            print("RECORDING")
            x = datetime.now().strftime('%Y-%m-%d-%H-%m-%s')
            camera.start_recording('video-' + x + '.h264')
            is_recording = 1
            led.on()

        elif (button.value == False) and (is_recording == 1):
            print("DONE RECORDING!")
            camera.stop_recording()
            is_recording = 0
            led.off()

except KeyboardInterrupt:
    print("INTERRUPTED!")
    button.close()
    camera.close()
    led.close()

Here is how I have it in /etc/rc.local: sudo python3 /path/to/file.py &

When I make file.py executable and add the above line to /etc/rc.local, following a reboot (when I would expect the script to run on its own) I am able to get the LED to light up but nothing happens with the camera (no new video files appear after pressing, holding, and then releasing the button). If I try to run rc.local manually at this point by simply running /etc/rc.local I get an error that ends with: picamera.exc.PiCameraMMALError: Failed to enable connection: Out of resources

I am totally stuck on this, as it works outside of /etc/rc.local reliably. Can someone tell me what I am doing incorrectly? I am trying to get a point and shoot video camera going here and this is problem is cramping my style.

Answer 1

Got in touch with the maintainer of the picamera library here and have resolved issues. Here is a list of changes that need to be made to get this to work:

1. start_recording() needs a full path to explicitly tell it where to save, otherwise it will save to /. I made the following changes to do so:

   x = datetime.now().strftime('%Y-%m-%d-%H-%m-%s')
   path = ''.join(['/home/pi/', x, '.h264'])
   camera.start_recording(path)
   

2. the line in /etc/rc.local needs to be written like this in order to run under the pi user and therefore properly save the file in /home/pi/: su -c "python3 /path/to/file.py" pi &

After making both of these changes the code in the initial question, which was apparently always working and just saving to a different place, will work properly.