Start Python Pygame automatically (with sudo rights) after booting instead of displaying a prompt

Question

I'm trying to solve this problem.

I would like to boot a raspbery directly into pygame without starting the GUI.

I have a raspberry pi generation 2 with the current "2021-01-11-raspios-buster-armhf.img" installed. This comes with an installation on python3.7 and pygame

I have a very simple pygame program that works, when I SSH into the pi as the "pi" user and run it with "sudo python3 pg.py" (Example code below). The program writes into the framebuffer "/dev/fb0" which causes a display that's on HDMI to show two images. Sudo rights are needed to allow pygame to access this buffer.

How can I get the pi to start this program as a sudo user on boot instead of showing a prompt?

I have set up the pi to boot into the promp for the "pi" user without starting the gui

After a boot I can type in

• "cd /opt/pygame_prototype"

• "sudo /usr/bin/python3 pg.py"

which starts pygame successfully.

So this is what I need to automate.

Any help would be welcome.

Program code pg.py

import logzero
from logzero import logger

logzero.logfile("/tmp/logzero-demo.log")
logger.info("info - autostart")

import os, pygame, time

logger.info(f"{time.time()}")


def setSDLVariables(driver):
    logger.info("Setting SDL variables...")
    os.environ["SDL_FBDEV"] = "/dev/fb0"
    os.environ["SDL_VIDEODRIVER"] = driver
    logger.info("...done")


def printSDLVariables():
    logger.info("Checking current env variables...")
    logger.info("SDL_VIDEODRIVER = {0}".format(os.getenv("SDL_VIDEODRIVER")))
    logger.info("SDL_FBDEV = {0}".format(os.getenv("SDL_FBDEV")))


setSDLVariables('fbcon')
printSDLVariables()
logger.info("Try init")
try:
    pygame.init()
except pygame.error:
    print("Driver '{0}' failed!".format(driver))
logger.info("init complete")
# size = (pygame.display.Info().current_w, pygame.display.Info().current_h)
size = (640, 480)
logger.info("Detected screen size: {0}".format(size))
try:
    screen = pygame.display.set_mode(size)
    clock = pygame.time.Clock()
    pygame.mouse.set_visible(False)
    i1 = pygame.image.load(r"1.jpg")
    i2 = pygame.image.load(r"2.png")
    for x in range(10):
        screen.fill((0, 0, 0))
        screen.blit(i1, (x, x))
        pygame.display.flip()
        clock.tick(1)
        screen.fill((200, 200, 0))
        screen.blit(i2, (x * 10, x * 10))
        pygame.display.flip()
        clock.tick(1)
except Exception as e:
    logger.info(e)
    raise

Answer 1

Looks like I tried too many complicated solutions, because I could not get it to work with systemd.

An easy sulation that works is adding the two commands to

/etc/rc.local above the "exit 0" line.

"cd /opt/pygame_prototype"
"/usr/bin/python3 pg.py"

This file is run with root rights at the end of the login process.