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Monday, 22 October 2018

Use of Power BI PushDatasets


In PowerBI, real-time streaming can be consumed in three (please visit https://docs.microsoft.com/en-us/power-bi/service-real-time-streaming ) different ways listed below:

  •  Consuming streaming data from Azure Stream Analytic
  •  Consuming streaming data from PubNub
  •  Consuming streaming data vis PushDataset


If you have got sensors which are emitting data and you want to visualize it in real-time, you can use PowerBI in conjunction with Azure Stream Analytics to build the dashboard. But if data is less frequent and you want to have a dashboards that auto-refreshes then you can use any one of three methods. In this post I will show how Push Datasets can be used to develop a dashboard.

Below is a simple architecture for this post:













We need following components to build a complete end-to-end simple solution shown in above diagram:

  1. Data Generator (to simulate data is coming to db at every x interval). This could your source which generates data less frequently.
  2. Console App (that pushes data to PowerBI PushDataset)
  3. PowerBI Dashboard


I have created a sample code that generates some data and inserts into database. Please see below code snippet:



The console application will be leveraging PowerBI REST API programming interface for pushing data. For this reason, console app needs to authenticate/authorize with PowerBI. So you need to register your console app with Azure AD in order to get OAuth token from Azure Authorization server. Please follow https://docs.microsoft.com/en-us/power-bi/developer/walkthrough-push-data-register-app-with-azure-ad to register your app.

OAuth provides four different OAuth flows based how you want to authenticate/authorize your application with Authorization server. Please visit https://auth0.com/docs/api-auth/which-oauth-flow-to-use to know which flow is best suited for your scenario.

I will be using Client Credential Flow (an OAuth flow which can be read at https://oauth.net/2/grant-types/client-credentials/ ) as console app will be treated as trusted application and also there would not be any human interaction if any authorization popup appears it would not be able to deal with.

Below is the code to get oauth token using Microsoft.IdentityModel.Clients.ActiveDirectory version 2.29.0 of nuget package:



I treat this scenario as syncing two systems (from source to target but target is PowerBI). Most of the syncing solution, we need to maintain what we have synced so far so that next time system should pick delta of data.
For this purpose, we are using ROWVERSION datatype which is auto generated by database. Please visit https://www.mssqltips.com/sqlservertip/4545/synchronizing-sql-server-data-using-rowversion/ for how to use rowversion for syncing scenario.

To maintain what has been synced, I have created a table to keep track the last row version, console application has sent to PowerBI, against a table like shown below:












For the first time, last row version should 0x000.

I also created a stored procedure that returns delta with the help of last row version and table name. Below is the stored procedure code:



Now, we got the data (delta amount), we need to send it to PushDataset in PowerBI. Every PushDataset has a unique id, and data needs to be sent to correct id.

I have created a dataset called “DeviceTelemetry” using REST API. To find the dataset id, you need to call the Power BI REST API like shown below:










And result is shown like below:








Now we got the Dataset Id as GUID, we need to use it to send data to Power BI. We will use PowerBI REST API to do this. You can do it in your console app to fetch all the datasets and grab the id for which you want to send to. For demonstration purpose I have shown you how you achieve it.

Now, the console app can you use dataset id and keep pushing data to it. Again you can leverage Power BI REST API to send data into batches or one by one. Below is a snapshot how I am sending data:









Here is the code that wraps to add rows to PowerBI PushDatasets leveraging api wrapper:


Here is the code for PowerBI Rest Api wrapped around a nice method:


Once your console app start sending data, you can go to PowerBI.com and start creating reports and dashboard like shown below:




Note that the dataset is listed as Push dataset.
Click on red boxed area (create report link) to create report as I created reports and composed them into one dashboard shown below:














That’s it so far.