Triggering Azure Functions in response to Azure SQL Database events

Question

Pulumi · Accepted Answer

Azure Functions can be used to run code in response to various events, including database operations. In this context, we'll set up an Azure Function triggered by events from an Azure SQL Database using Azure Event Grid and Azure Logic Apps as an intermediary. Azure does not natively support direct triggers from Azure SQL Database to Azure Functions, so one way to achieve this is to use Logic Apps to monitor the database for changes and then call an Azure Function when certain events occur.

Here's how the flow works:
1. Azure SQL Database performs an operation, such as inserting a row.
2. Azure Logic Apps has a SQL connector that can be used to monitor the database for specific events or changes.
3. Once the Logic App detects the event, it triggers an Azure Function.
4. The Azure Function executes the business logic based on the event.

For our program, we will focus on setting up an Azure Function and presume that you've already set up an Azure SQL Database. Configuring an Azure Logic App for event monitoring is beyond the scope of Pulumi's infrastructure as code (IaC), and would likely require setting up the Logic App workflow through the Azure Portal or via an ARM template, which can then be deployed using Pulumi.

Below is a TypeScript program that uses Pulumi to create an Azure Function App configured for a Windows environment:

```typescript
import * as pulumi from "@pulumi/pulumi";
import * as azure from "@pulumi/azure";

// Create an Azure Resource Group
const resourceGroup = new azure.core.ResourceGroup("resourceGroup", {
    location: "West US",
});

// Create an Azure Storage Account required by the Function App
const storageAccount = new azure.storage.Account("storageAccount", {
    resourceGroupName: resourceGroup.name,
    location: resourceGroup.location,
    accountTier: "Standard",
    accountReplicationType: "LRS",
});

// Create an Azure App Service Plan
const appServicePlan = new azure.appservice.Plan("appServicePlan", {
    resourceGroupName: resourceGroup.name,
    location: resourceGroup.location,
    kind: "FunctionApp",
    sku: {
        tier: "Dynamic",
        size: "Y1",
    },
});

// Create an Azure Function App
const functionApp = new azure.appservice.FunctionApp("functionApp", {
    resourceGroupName: resourceGroup.name,
    location: resourceGroup.location,
    appServicePlanId: appServicePlan.id,
    storageAccountName: storageAccount.name,
    storageAccountAccessKey: storageAccount.primaryAccessKey,
    appSettings: {
        WEBSITE_RUN_FROM_PACKAGE: "https://mystorageaccount.blob.core.windows.net/mycontainer/myzipfile.zip", // This is a dummy URL, replace it with the URL of your function code zip
        // Additional settings here
    },
    httpsOnly: true,
});

// Export the Function App URL
export const endpoint = functionApp.defaultHostname.apply(hostname => `https://${hostname}/api/{functionName}`);
```

In this code, we:

- Create a Resource Group to hold our Azure Function and related resources.
- Set up a Storage Account which is necessary for an Azure Function App.
- Define an App Service Plan that describes the pricing tier and instance size for the function.
- Deploy a Function App where you'd deploy your actual function code.
  - You'd need to replace the `WEBSITE_RUN_FROM_PACKAGE` setting with the URL pointing to a zip file containing your Azure Function code. This can be hosted in a Storage Blob, for example.

When you deploy this program with Pulumi, it will provision the necessary infrastructure and output the hostname of your Function App. You can then integrate your Logic App with the Function App, using this hostname to trigger functions upon database events.

Keep in mind that for actual use, you'd need to integrate with source control or some CI/CD pipeline mechanism to deploy your function code to the Function App. This might involve additional configuration outside the scope of this Pulumi program.