led state can now be handled across multiple processes

server/drivers/apa102.py

@@ -1,5 +1,6 @@
 import spidev
 import logging as log
+from multiprocessing import Array as multiprocessing_array
 
 """
 Driver for APA102 LEDS (aka "DotStar").
@@ -21,6 +22,10 @@
  - combineColor
  - wheel
 
+
+If the parameter multiprocessing is enabled in the constructor, the LED buffer is stored in a static array which is
+available to all processes of apa102.py
+
 The rest of the methods are used internally and should not be used by the user of the library.
 
 Very brief overview of APA102: An APA102 LED is addressed with SPI. The bits are shifted in one by one,
@@ -59,13 +64,16 @@
 
 
 class APA102:
- def __init__(self, numLEDs, globalBrightness=31, order='rgb', max_spi_speed_hz=8000000):
+ def __init__(self, numLEDs, globalBrightness=31, order='rgb', max_spi_speed_hz=8000000, multiprocessing=False):
  self.numLEDs = numLEDs
  order = order.lower()
  self.rgb = rgb_map.get(order, rgb_map['rgb'])
  # LED startframe is three "1" bits, followed by 5 brightness bits
  self.setGlobalBrightness(brightness=globalBrightness, update_buffer=False)
  self.leds = [self.ledstart, 0, 0, 0] * self.numLEDs # Pixel buffer
+ self.multiprocessing = multiprocessing # if multiprocessing enabled: convert array to a shared state
+ if self.multiprocessing:
+ self.leds = multiprocessing_array('i', self.leds)
  self.spi = spidev.SpiDev() # Init the SPI device
  self.spi.open(0, 1) # Open SPI port 0, slave device (CS) 1
  self.spi.max_speed_hz = max_spi_speed_hz # should not be higher than 8000000
@@ -202,6 +210,8 @@ def setPixelRGB(self, ledNum, rgbColor):
  def rotate(self, positions=1):
  cutoff = 4 * (positions % self.numLEDs)
  self.leds = self.leds[cutoff:] + self.leds[:cutoff]
+ if self.multiprocessing:
+ self.leds = multiprocessing_array('i', self.leds)
 
  """
  void show()
@@ -211,7 +221,7 @@ def rotate(self, positions=1):
 
  def show(self):
  self.clockStartFrame()
- self.spi.xfer2(self.leds) # SPI takes up to 4096 Integers. So we are fine for up to 1024 LEDs.
+ self.spi.xfer2(list(self.leds)) # SPI takes up to 4096 Integers. So we are fine for up to 1024 LEDs.
  self.clockEndFrame()
 
  """

server/mqtt/MQTTControl.py

@@ -121,8 +121,6 @@ def stop_running_show(timeout_sec: int = 0.5):
  else:
  log.info("no show running; all good")
 
- strip.clearBuffer() # just in case
-
 
 def set_strip_brightness(brightness: int):
  global conf, strip
@@ -146,7 +144,11 @@ def run(config) -> None:
  log.info("Starting {name}".format(name=conf.sys_name))
 
  log.info("Initializing LED strip...")
- strip = APA102(conf.strip.num_leds, conf.strip.initial_brightness, 'rgb', conf.strip.max_spi_speed_hz)
+ strip = APA102(numLEDs=conf.strip.num_leds,
+ globalBrightness=conf.strip.initial_brightness,
+ order='rgb',
+ max_spi_speed_hz=conf.strip.max_spi_speed_hz,
+ multiprocessing=True)
 
  log.info("Connecting to the MQTT broker")
  client = mqtt.Client()