So, I misunderstood what is_alive is supposed to do.

lighting.py

@@ -30,6 +30,7 @@ class ColorManager(Thread):
  current_color = Color(0, 0, 0)
  activeFlag = True
  spi = spidev.SpiDev()
+ running = True
 
  def __init__(self):
  super().__init__()
@@ -59,6 +60,9 @@ class ColorManager(Thread):
  if self.current_color.green > 0:
  self.current_color.green -= 1
 
+ def stop(self):
+ self.running = False
+
  def start_fade(self):
  self.activeFlag = False
 
@@ -66,7 +70,7 @@ class ColorManager(Thread):
  self.unscaled_blue = 0
 
  def run(self):
- while self.is_alive():
+ while self.running:
  if self.activeFlag:
  self.get_color()
  else:
@@ -111,6 +115,7 @@ def main():
  cm.start_fade()
  elif messagedata == b"abort":
  cm.lights_off()
+ cm.stop()
  else:
  print("Unhandled message")