python: add masterkey sample

RaspberryPi/README.md

@@ -1,11 +1,10 @@
-## Azure IoT Central Reference Firmware for Raspberry Pi 2/3
+## Azure IoT reference application for Raspberry Pi 2/3 (using python)
 
 ### Description
 
-An example of writing a firmware solution to send data to Azure IoT Central and
-to receive events back from Azure IoT Central to be processed by the device.
-You are free to take this code and the concepts used, and use them as a basis
-for your own firmware for Azure IoT Central.
+An example python app to..
+- send data to Azure IoT Central
+- receive events back from Azure IoT Central to be processed by the device.
 
 ### How to run
 
@@ -20,12 +19,11 @@ Install [azure iot central python client](https://pypi.org/project/iotc/) `iotc`
 pip install iotc
 ```
 
-Go create an application
 Fill the information below (under app.py).
 ```
 deviceId = "DEVICE_ID"
 scopeId = "SCOPE_ID"
-mkey = "DEVICE_KEY"
+deviceKey = "DEVICE_KEY"
 ```
 
 Run!
@@ -35,3 +33,8 @@ python app.py
 ```
 
 Python 2/3 and micropython(*) are supported.
+
+
+#### Using master key for producing deviceKey on runtime
+
+Take a look at the `appMasterKey.py` sample

RaspberryPi/app.py

@@ -7,9 +7,9 @@ from random import randint
 
 deviceId = "DEVICE_ID"
 scopeId = "SCOPE_ID"
-mkey = "PRIMARY/SECONDARY device KEY"
+deviceKey = "PRIMARY/SECONDARY device KEY"
 
-iotc = iotc.Device(scopeId, mkey, deviceId, IOTConnectType.IOTC_CONNECT_SYMM_KEY)
+iotc = iotc.Device(scopeId, deviceKey, deviceId, IOTConnectType.IOTC_CONNECT_SYMM_KEY)
 iotc.setLogLevel(IOTLogLevel.IOTC_LOGGING_API_ONLY)
 
 gCanSend = False

RaspberryPi/appMasterKey.py

@@ -0,0 +1,74 @@
+# Copyright (c) Microsoft. All rights reserved.
+# Licensed under the MIT license.
+
+import sys
+import iotc
+from iotc import IOTConnectType, IOTLogLevel
+from random import randint
+import base64
+import hmac
+import hashlib
+
+gIsMicroPython = ('implementation' in dir(sys)) and ('name' in dir(sys.implementation)) and (sys.implementation.name == 'micropython')
+
+def computeKey(secret, regId):
+  global gIsMicroPython
+  try:
+    secret = base64.b64decode(secret)
+  except:
+    print("ERROR: broken base64 secret => `" + secret + "`")
+    sys.exit()
+
+  if gIsMicroPython == False:
+    return base64.b64encode(hmac.new(secret, msg=regId.encode('utf8'), digestmod=hashlib.sha256).digest())
+  else:
+    return base64.b64encode(hmac.new(secret, msg=regId.encode('utf8'), digestmod=hashlib._sha256.sha256).digest())
+
+deviceId = "DEVICE_ID"
+scopeId = "SCOPE_ID"
+masterKey = "PRIMARY/SECONDARY master Key"
+
+deviceKey = computeKey(masterKey, deviceId)
+
+iotc = iotc.Device(scopeId, deviceKey, deviceId, IOTConnectType.IOTC_CONNECT_SYMM_KEY)
+iotc.setLogLevel(IOTLogLevel.IOTC_LOGGING_API_ONLY)
+
+gCanSend = False
+gCounter = 0
+
+def onconnect(info):
+  global gCanSend
+  print("- [onconnect] => status:" + str(info.getStatusCode()))
+  if info.getStatusCode() == 0:
+     if iotc.isConnected():
+       gCanSend = True
+
+def onmessagesent(info):
+  print("\t- [onmessagesent] => " + str(info.getPayload()))
+
+def oncommand(info):
+  print("- [oncommand] => " + info.getTag() + " => " + str(info.getPayload()))
+
+def onsettingsupdated(info):
+  print("- [onsettingsupdated] => " + info.getTag() + " => " + info.getPayload())
+
+iotc.on("ConnectionStatus", onconnect)
+iotc.on("MessageSent", onmessagesent)
+iotc.on("Command", oncommand)
+iotc.on("SettingsUpdated", onsettingsupdated)
+
+iotc.connect()
+
+while iotc.isConnected():
+  iotc.doNext() # do the async work needed to be done for MQTT
+  if gCanSend == True:
+    if gCounter % 20 == 0:
+      gCounter = 0
+      print("Sending telemetry..")
+      iotc.sendTelemetry("{ \
+\"temp\": " + str(randint(20, 45)) + ", \
+\"accelerometerX\": " + str(randint(2, 15)) + ", \
+\"accelerometerY\": " + str(randint(3, 9)) + ", \
+\"accelerometerZ\": " + str(randint(1, 4)) + "}")
+
+    gCounter += 1