Readme.md

Introduction

Continuing with Matt Allford's (@mattallford) CloudSkill's course Azure Functions for DevOps Engineers, I looked into function triggers, bindings, and outputs.

Prerequisite

• Azure Subscription
• PowerShell knowledge

Use Case

• Take input from a trigger and use it in the function
• Output data to other resources

Try yourself

The next section of the course goes through how to take data from the trigger for the function and use it in the function. All functions have a trigger, whether it's an HTTP trigger, a timer, or an event that happens elsewhere in Azure.

In this example, we built a trigger based on an event grid event, such as deleting a resource group. Every action in Azure creates an event in event grid, so we can easily key of these actions for our function to trigger.

For the function, the incoming data from the event grid is defined as a parameter named $eventGridEvent:

param($eventGridEvent, $TriggerMetadata)

Once we know the event occurred (in this case, deleting a resource group), you can manipulate the data from the event and do something with it, like so:

# Gather data from the function trigger paylod
$EventSubject = $eventGridEvent.subject -split "/"
$ResourceGroupName = $EventSubject[-1]
$user = $eventGridEvent.data.claims.'http://schemas.xmlsoap.org/ws/2005/05/identity/claims/upn'
$SubscriptionID = $eventGridEvent.data.subscriptionId

# Collect data from the event ready to send to Azure Table Storage
$TableData = [PSCustomObject]@{
    partitionKey = $eventGridEvent.eventTime
    rowkey = $eventGridEvent.id
    ResourceGroupName = $ResourceGroupName
    User = $user
}

We can then output the data into another Azure resource. For this example, we created an output binding named outputTable to store the event data into an Azure Table Storage. What's great is within the PowerShell code you don't need to know a lot of specifics for how to put this data into the table. You can use the Push-OutputBinding cmdlet with the name of the binding to put the data into the table:

Push-OutputBinding -Name outputTable -Value $TableData

This will create the table if it doesn't exist and store the $TableData there.

Here's what the full integration map looks like:

Next Steps

Continuing to the next lesson that covers various settings within the function app including storing environmental variables, keys, managed identities, and networking.

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