Microsoft Azure Iot Hub Library

The Zerynth Microsoft Azure Iot Hub Library can be used to ease the connection to Microsoft Azure Iot Hub.

It allows to make your device act as a Microsoft Azure Iot Hub Device which can be registered through Azure command line tools or Azure web dashboard.

The Device class

class Device(hub_id, device_id, api_version, key, timestamp_fn, token_lifetime=60)

Create a Device instance representing a Microsoft Azure Iot Hub Device.

The Device object will contain an mqtt client instance pointing to Microsoft Azure Iot Hub MQTT broker located at The client is configured with device_id as MQTT id and is able to connect securely through TLS and authenticate through a SAS token with a token_lifetime minutes lifespan.

Valid tokens generation process needs current timestamp which will be obtained calling passed timestamp_fn. timestamp_fn has to be a Python function returning an integer timestamp. A valid base64-encoded primary or secondary key key is also needed.

The api_version string is mandatory to enable some responses from Azure MQTT broker on specific topics.

The client is accessible through mqtt instance attribute and exposes all Zerynth MQTT Client methods so that it is possible, for example, to setup custom callbacks on MQTT commands (though the Device class already exposes high-level methods to setup Azure specific callbacks). The only difference concerns mqtt.connect method which does not require broker url and ssl context, taking them from Device configuration:

def timestamp_fn():
    valid_timestamp = 1509001724
    return valid_timestamp

key = "ZhmdoNjyBccLrTnku0JxxVTTg8e94kleWTz9M+FJ9dk="
my_device = iot.Device('my-hub-id', 'my-device-id', '2017-06-30', key, timestamp_fn)

Set a callback to be called on cloud to device messages.

bound_cbk callback will be called passing a string containing sent message and a dictionary containing sent properties:

def bound_callback(msg, properties):
    print('c2d msg:', msg)
    print('with properties:', properties)

on_method(method_name, method_cbk)

Set a callback to respond to a direct method call.

method_cbk callback will be called in response to method_name method, passing a dictionary containing method payload (should be a valid JSON):

def send_something(method_payload):
    if method_payload['type'] == 'random':
        return (0, {'something': random(0,10)})
    deterministic = 5
    return (0, {'something': deterministic})

my_device.on_method('get', send_something)

method_cbk callback must return a tuple containing response status and a dictionary or None as response payload.


Set a callback to respond to cloud twin updates.

twin_cbk callback will be called when a twin update is notified by the cloud, passing a dictionary containing desired twin and an integer representing current twin version:

def twin_callback(twin, version):
    print('new twin version:', version)


It is possible for twin_cbk to return a dictionary which will be immediately sent as reported twin.

report_twin(reported, wait_confirm=True, timeout=1000)

Report reported twin.

reported twin must be a dictionary and will be sent as JSON string. It is possible to not wait for cloud confirmation setting wait_confirm to false or to set a custom timeout (-1 to wait forever) for the confirmation process which could lead to TimeoutException.

An integer status code is returned after cloud confirmation.


Get current twin containing desired and reported fields. It is possible set a custom timeout (-1 to wait forever) for the process which could lead to TimeoutException.

An integer status code is returned after cloud response along with received twin JSON-parsed dictionary.

publish_event(event, properties)

Publish a new event event with custom properties. event must be a dictionary and will be sent as json string. properties must be a dictionary and will be sent as an url-encoded property bag.