Miscrosoft Azure IoT

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mongoose-os-libs/azure mgos_azure.h   api_azure.js

This library provides Azure IoT Hub support for Mongoose OS.

Currently only plain MQTT is supported.

See Azure IoT + Mongoose OS tutorial at https://mongoose-os.com/docs/cloud/azure.md


Authentication by both SAS token and X.509 certificate is supported. See the Authentication section of the documentation for explanation.

mos azure-iot-setup

The easiest way to setup Azure cloud connection is by using mos azure-iot-setup. Makes sure you have the az CLI tool installed, create an IoT Hub, then run:

$ mos azure-iot-setup --azure-hub-name MY-HUB-NAME --azure-device-id NEW-DEVICE-ID

SAS Token

To use symmetric key authentication, obtain the connection string from the web interface or by using the az CLI utility:

$ az iot hub device-identity show-connection-string --hub-name my-hub --device-id test1
  "cs": "HostName=my-hub.azure-devices.net;DeviceId=test1;SharedAccessKey=AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA="

Enable the Azure client and set the azure.cs config setting:

$ mos config-set azure.enable=true "azure.cs=HostName=my-hub.azure-devices.net;DeviceId=test1;SharedAccessKey=AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA="

X.509 Certificate

To use authentication by an X.509 certificate, upload the certificate and private key files in PEM format on the device and configure azure.host_name, azure.device_id, azure.cert and azure.key:

$ mos put test4.crt.pem
$ mos put test4.key.pem
$ mos config-set azure.enable=true azure.host_name=my-hub.azure-devices.net azure.device_id=test4 \
                 azure.cert=test4.crt.pem azure.key=test4.key.pem

Note: It is possible to store private key in a cryptochip, such as ATECC508A (for example, as described here for Google IoT Core). Just specify azure.key=ATCA:0 to use private key in slot 0 of the chip. [mos azure-iot-setup] supports ATECC508 key storage - just add --use-atca to the setup command above.


bool mgos_azure_send_d2c_msg(const struct mg_str props,
                             const struct mg_str body);

Send a Device to Cloud message. If present, the properties string must be URL-encoded.


bool mgos_azure_send_d2c_msgf(const struct mg_str props, const char *json_fmt,

A variant of mgos_azure_send_d2c_msg that formats a JSON message.


bool mgos_azure_send_d2c_msgp(const struct mg_str *props,
                              const struct mg_str *body);

A variant of mgos_azure_send_d2c_msg that takes pointers, for easy FFI.


struct mg_str mgos_azure_get_host_name(void);

Returns host name of the Azure hub


struct mg_str mgos_azure_get_device_id(void);

Returns Azure device ID


bool mgos_azure_is_connected(void);

Returns true if Azure connection is up, false otherwise.


bool mgos_azure_dm_response(struct mg_str id, int status,
                            const struct mg_str *resp);

Respond to a Direct Method call.


bool mgos_azure_dm_responsef(struct mg_str id, int status, const char *json_fmt,

Respond to a Direct Method call with a JSON message.


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