One of our applications in our “test playground” is running some code in an Azure WebApp that needs to be restarted once in a while. Rather than trying to fix the underlying problem (no fun in that right?), I decided to create a small mobile app to restart the WebApp when needed. To make it a bit more fun, I used the following “code-less” solutions to make it work:
- Azure Automation: Graphical Runbook to restart the WebApp; use a Webhook to call the Runbook using a simple HTTP POST
- Microsoft Flow: calls the Azure Automation Webhook when a control is selected in a PowerApp
- PowerApp: simple app with a button that calls the above Flow
Azure Automation
I created an Azure Automation account with the option to create a service principal. This results in an account that is added as Contributor for the subscription in which the Azure Automation account was created. This also means that a runbook that uses this account is allowed to restart a WebApp in the same subscription. In my case, the Automation Account and the WebApp are in the same subscription.
Now, before you can use the Restart-AzureRMWebApp cmdlet, you need to add the AzureRM.Websites module to the Automation Account. To do so, navigate to https://www.powershellgallery.com/packages/AzureRM.Websites/1.1.2 and use the Deploy to Azure Automation button. Follow the instructions to add the module to an existing Azure Automation account. When you are finished, click Assets in the Automation Account’s main pane and then click Modules. You should see the following:
Now you can duplicate the AzureAutomationTutorial graphical runbook. In Runbooks, click that Runbook and use the Export option to export the definition to a local file on your computer. Now add a new Runbook and use the Import an existing runbook option together with the export file you just created. Your copied Runbook will look like below:
You can remove everything after Login to Azure (that’s the login with the Service Principal that has Contributor rights). Just add the Restart-AzureRMWebApp cmdlet like so:
The Restart-AzureRmWebApp only needs two parameters: the name of the WebApp and the resource group of the WebApp. To be able to call the Runbook using HTTP POST, create a Webhook for it. In the properties of the Runbook, click Webhooks and then add a Webhook. Note that there is no authentication for these Webhooks. It’s just a long, unique URL with an expiration date that you set. Make sure you copy the URL before you save the Webhook because it will not be shown later. I created a RunFromPowerApps webhook like so:
You can try the Webhook with Postman (https://www.getpostman.com/) or curl and see if a job gets started.
Microsoft Flow
Well, this could not be simpler. Go to https://flow.microsoft.com and login with your credentials (the same credentials for PowerApps, in my case they are Azure AD organization credentials). From My flows create a new flow that looks like this:
In the URI, enter the Webhook address from Azure Automation. Save the flow. We will now use this flow in PowerApps.
PowerApps
To create a PowerApp, install the Windows PowerApp application (a Windows Store app) and logon with the same credentials you used with Flow. I created a blank app with a simple button, nothing fancy. With the button selected, click Flows from the Action menu. You should see the flow you created. Just select it to link it to the button selection. You should see something like:
Note that it is possible to pass data to the flow as parameters to the Run() command. You could for instance create a list of WebApps to restart and pass the WebApp to be restarted to the Flow and the Webhook.
Test the PowerApp with the play button in the menu bar. When you click Restart, check that the Automation Job fired properly:
Now you can run the PowerApp on your iOS or Android device with the PowerApp app for those platforms. Enjoy!
This simple example shows that a lot can be accomplished with tools like Azure Automation, Flow and PowerApps for prototyping or even actual applications with a quick time to value.
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