App Functions SDK Azure Extension

Overview

This is an extension to the App Functions SDK providing integration with Azure IoT hub in an easy way. It provides one transform and one export fucntion specific to the Azure IoT.

The Azure Transform Function

This transform function can be used in the middle stage of the the function pipeline as other transforms. It will transform EdgeX events to name-value format to be consumed by Azure IoT Hub as the one below:

{  
   "RandomValue_Int16":"32417"
}

The Azure MQTT Export Function

This function can export transformed readings to Azure IoT via MQTT using some simple configurations. It also supports loading the required key/certificate pair from Vault (the distributed secret store used in the EdgeX architecture) in addition to key/certificate files from local file system. Just include a section of related configurations under ApplicationSettings in the app-functions standard toml configuration file as following:

IoTHub         = "EdgeX"
IoTDevice      = "MyDevice"
TokenPath      = "/vault/config/assets/resp-init.json"
VaultHost      = "localhost"
VaultPort      = "8200"
CertPath       = "v1/secret/edgex/pki/tls/azure"
MQTTCert       = "/secret/rsa_cert.pem"
MQTTKey        = "/secret/rsa_private.pem"

• IoTHub - Name of Azure IoT Hub
• IoTDevice - Name on Azure IoT Device
• TokenPath, VaultHost, VaultPort and CertPath - Info for retrieving key/cert from Vault secret store
• MQTTCert and MQTTKey - Key/Certificate pait from loca file system. The pair will be used when the function fails to load a pair from Vault.

You can use LoadAzureMQTTConfig() to load the configurations to struct AzureMQTTConfig or create one yourself if the standard app-function sdk configuration file does not suit your needs.

See the code under examples/azure-export for a complete working example exporting reading to Azure IoT Hub.