IoTHub, Blob Storage and Function App. Configuring Cold and Hot path of data processing.

3 min readJun 12, 2018

In this article I will tell you how to build efficient and working workflow of the same data from IoTHub into Function App and Blob storage.

IoTHub

To create IotHub check official docs — create IotHub

Device Emulators

How to create Device Emulator check official docs — create device emulators for IoTHub

Blob storage

To create Blob storage check official docs — create storage

Function App Service Plan

To create function app service itself check official docs — create function app

Configuring Function App

After creating App Service Plan for Function App we have to create proper type of our function itself. We have to choose right trigger for it.

Choose create new function with EventHub trigger:

Run the function as it is to open log streaming and see what is going on.

Logs:

> 2018-06-18T19:06:43 Welcome, you are now connected to log-streaming service. > 2018-06-18T19:07:04.568 [Info] Function started (Id=a60af5f3-ad37-4a45-a450-2c3ac89fca81) > 2018-06-18T19:07:04.583 [Info] C# Event Hub trigger function processed a message: Test Message > 2018-06-18T19:07:04.583 [Info] Function completed (Success, Id=a60af5f3-ad37-4a45-a450-2c3ac89fca81, Duration=11ms)

Run your Device Emulator to check if messages are received via Function App.

Logs:

> 2018-06-18T19:06:43 Welcome, you are now connected to log-streaming service. > 2018-06-18T19:07:04.568 [Info] Function started (Id=a60af5f3-ad37-4a45-a450-2c3ac89fca81) > 2018-06-18T19:07:04.583 [Info] C# Event Hub trigger function processed a message: Test Message > 2018-06-18T19:07:04.583 [Info] Function completed (Success, Id=a60af5f3-ad37-4a45-a450-2c3ac89fca81, Duration=11ms) > 2018-06-18T19:08:43 No new trace in the past 1 min(s). > 2018-06-18T19:09:43 No new trace in the past 2 min(s). > 2018-06-18T19:09:56.815 [Info] Function started (Id=2d9db652-62e6-4ab9-a9a5-ddf8be7d23e4) > 2018-06-18T19:09:56.815 [Info] C# Event Hub trigger function processed a message: {"deviceId":"AAABBB","time":1529348996,"seqNumber":1,"data":"3015001E0004186DEA983F80","snr":0,"station":"","rssi":0,"ack":false} > 2018-06-18T19:09:56.815 [Info] Function completed (Success, Id=2d9db652-62e6-4ab9-a9a5-ddf8be7d23e4, Duration=0ms) > 2018-06-18T19:09:57.862 [Info] Function started

Nice, we are receiving messages into our IotHub and from IotHub they are delivered into Function App

Configuring Route and Endpoint for `Cold` and `Hot` path

Endpoint

Go to your IoTHub and add new Custom Endpoint. Even in Free plan in IoTHub you are able to create one additional custom endpoint, what is enough for our case.

Routes

After add two new Routes.

First to send data into Blob storage.

Second to send data into events endpoint, to which is connected our function app trigger.

Rules for Routes should be the same.After restart your Device Emulators.

You should see your message ariving in your Function app logs and after Batch frequency seconds, you should have file created in your Blob storage.

Attention. Files in Blob Storage are saved in serialized format — AVRO. So when you will access file you will see not human readable data.

Originally published at kutsyk.github.io on June 12, 2018.