Handling Multipart/File Uploads in Azure Functions

Introduction

This guide aims to provide a comprehensive walkthrough on setting up an Azure Function to handle file uploads using multipart/form-data. We will cover the deployment of the necessary Azure infrastructure, including a Function App and a Storage Account, to efficiently manage and store uploaded files. By the end of this guide, you will have a clear understanding of how to configure and link these resources to enable file uploads in your Azure Functions.

Program Overview

The following example:

• Sets up an Azure Function App.
• Configures a Storage Account to store uploaded files.
• Links the Azure Function App with the Storage Account.
• Defines stack exports for function endpoint and storage account.

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

// Resource group
const example = new azure.core.ResourceGroup("example", {
    name: "example-resources",
    location: "West Europe",
});
// Storage account for file uploads
const exampleAccount = new azure.storage.Account("example", {
    name: "examplestorageacct",
    resourceGroupName: example.name,
    location: example.location,
    accountTier: "Standard",
    accountReplicationType: "LRS",
});
// App Service plan
const examplePlan = new azure.appservice.Plan("example", {
    name: "example-appserviceplan",
    location: example.location,
    resourceGroupName: example.name,
    sku: {
        tier: "Dynamic",
        size: "Y1",
    },
});
// Azure Function app
const exampleFunctionApp = new azure.appservice.FunctionApp("example", {
    name: "example-functionapp",
    location: example.location,
    resourceGroupName: example.name,
    appServicePlanId: examplePlan.id,
    storageAccountName: exampleAccount.name,
    storageAccountAccessKey: exampleAccount.primaryAccessKey,
    appSettings: {
        FUNCTIONS_WORKER_RUNTIME: "node",
        WEBSITE_RUN_FROM_PACKAGE: "1",
    },
});
export const functionEndpoint = exampleFunctionApp.defaultHostname;
export const storageAccountName = exampleAccount.name;
export const storageAccountKey = exampleAccount.primaryAccessKey;

Step-by-Step Explanation

1. Resource Group: A resource group named “example-resources” is created to manage all related resources in a specific location, “West Europe.”
2. Storage Account: A storage account is set up to hold the files being uploaded. It’s named “examplestorageacct” and configured with standard tier and locally-redundant storage (LRS).
3. App Service Plan: An app service plan is created to provide the necessary compute resources for running the Function App. It’s configured with a dynamic pricing tier.
4. Function App: The Azure Function App is created and configured to handle HTTP requests, specifically multipart/form-data for file uploads. The app settings ensure it runs with the Node.js runtime and uses package deployment.

Summary

In this guide, we successfully set up an Azure Function capable of handling multipart file uploads. We configured a storage account to store the uploaded files and linked it with the Function App. By exporting the function endpoint and storage account credentials, we ensured easy access for further operations. This setup allows for efficient handling and storage of file uploads in Azure Functions.