add python flasher

ota.py

+#!/usr/bin/python3
+
+# TODO: read from header?
+BROKER = "mqtt.c3pb.hack"
+DEVICE = "my-device"
+
+
+import sys
+import paho.mqtt.client as mqtt
+
+
+def on_connect(client, *ignored):
+  client.subscribe("device/" + DEVICE + "/ota/progress")
+
+  with open("build/qthing.bin", mode="rb") as f:
+    client.publish("device/" + DEVICE + "/ota/$firmware", payload=f.read())
+
+def on_message(client, userdata, msg):
+  progress = int(msg.payload)
+
+  if progress == 0:
+    print("OTA progress:")
+  
+  sys.stdout.write("\r[" + "#"*progress + " "*(100-progress) + "] " + str(progress) + "%")
+  sys.stdout.flush()
+
+  if progress == 100:
+    print("\nOTA successful")
+    if "--restart" in sys.argv:
+      print("restarting device")
+      client.publish("device/" + DEVICE + "/command", "restart")
+    else:
+      exit(0)
+
+def on_publish(client, userdata, _ignored):
+  if userdata.first_pub_done:
+    exit(0)
+  userdata.first_pub_done = True
+
+class Userdata(object):
+  first_pub_done = False
+
+client = mqtt.Client(userdata=Userdata())
+client.on_connect = on_connect
+client.on_message = on_message
+client.on_publish = on_publish
+
+client.connect(BROKER)
+client.loop_forever()