connection.py

from .env import Env
from .auxiliary import Color

from threading import Thread
import time
import sys
import struct
import json
import uuid

HEADER_FORMAT = '>HII'
ENV = Env()
COLOR = Color()

class FarmbotConnection(Thread):
  def __init__(self):
    Thread.__init__(self)
    if not ENV.farmware_api_available():
      return
    self.running = False
    self.buffer = []

    print(COLOR.error(f'opening request pipe {ENV.request_pipe}'), file=sys.stderr)
    self.requestPipe = open(ENV.request_pipe, 'wb')

    print(COLOR.error(f'opening response pipe {ENV.response_pipe}'), file=sys.stderr)
    self.responsePipe = open(ENV.response_pipe, 'rb')

  def __del__(self):
    print(COLOR.error(f'Closing pipes'), file=sys.stderr)
    self.requestPipe.close()
    self.requestPipe = None
    self.responsePipe.close()
    self.responsePipe = None

  def start(self):
    print(COLOR.error("Starting thread"), file=sys.stderr)
    self.running = True
    Thread.start(self)

  def stop(self):
    print(COLOR.error("Stopping thread"), file=sys.stderr)
    self.running = False
    Thread.join(self)

  def request(self, payload):
    self.buffer.append(payload)

  def run(self):
    while True:
      if not self.running:
        break

      nextPayload = None
      if not self.buffer:
        nextPayload = {
          'kind': 'rpc_request',
          'args': {'label': str(uuid.uuid4())},
          'body': [{'kind': 'nothing', 'args': {}}]}
      else:
        nextPayload = self.buffer.pop(0)

      if nextPayload:
        message_bytes = bytes(json.dumps(nextPayload), 'utf-8')
        header = struct.pack(HEADER_FORMAT, 0xFBFB, 0, len(message_bytes))
        self.requestPipe.write(header + message_bytes)
        self.requestPipe.flush()

        print(COLOR.error(f'reading 10 bytes'), file=sys.stderr)
        header = self.responsePipe.read(10)
        if header == b'':
            print(COLOR.error('No response from FBOS'), file=sys.stderr)
        (_, _, size) = struct.unpack(HEADER_FORMAT, header)
        print(COLOR.error(f'read {len(header)} bytes'), file=sys.stderr)
        json.loads(self.responsePipe.read(size).decode())


      print(COLOR.error("inside thread"), file=sys.stderr)
      time.sleep(1)

farmware.py

#!/usr/bin/env python
from farmware_tools.connection import FarmbotConnection
from farmware_tools.device import log
import time

farmbot = FarmbotConnection()
farmbot.start()
payload = log("hello world")
farmbot.request(payload)
time.sleep(10)
farmbot.stop()