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Quickstart: Create a C# function in Azure using Visual Studio Code

  • Article
  • 8 minutes to read

In this article, you use Visual Studio Code to create a C# function that responds to HTTP requests. After testing the code locally, you deploy it to the serverless environment of Azure Functions. This article creates an HTTP triggered function that runs on .NET 6.0. There's also a CLI-based version of this article.

By default, this article shows you how to create C# functions that runs on .NET 6 in the same process as the Functions host. These in-process C# functions are only supported on Long Term Support (LTS) versions of .NET, such as .NET 6. To create C# functions on .NET 6 that can also run on .NET 5.0 and .NET Framework 4.8 (in preview) in an isolated process, see the alternate version of this article.

Completing this quickstart incurs a small cost of a few USD cents or less in your Azure account.

Configure your environment

Before you get started, make sure you have the following requirements in place:

You also need an Azure account with an active subscription. Create an account for free.

Create your local project

In this section, you use Visual Studio Code to create a local Azure Functions project in C#. Later in this article, you'll publish your function code to Azure.

  1. Choose the Azure icon in the Activity bar, then in the Workspace (local) area, select the + button, choose Create Function in the dropdown. When prompted, choose Create new project.

    Screenshot of create a new project window.

  2. Select the directory location for your project workspace and choose Select. You should either create a new folder or choose an empty folder for the project workspace. Don't choose a project folder that is already part of a workspace.

  3. Provide the following information at the prompts:

    Prompt Selection
    Select a language Choose C#.
    Select a .NET runtime Select .NET 6.
    Select a template for your project's first function Choose HTTP trigger.
    Provide a function name Type HttpExample.
    Provide a namespace Type My.Functions.
    Authorization level Choose Anonymous, which enables anyone to call your function endpoint. To learn about authorization level, see Authorization keys.
    Select how you would like to open your project Select Add to workspace.

    Note

    If you don't see .NET 6 as a runtime option, check the following:

    • Make sure you have installed the .NET 6.0 SDK.
    • Press F1 and type Preferences: Open user settings, then search for Azure Functions: Project Runtime and change the default runtime version to ~4.

  4. Visual Studio Code uses the provided information and generates an Azure Functions project with an HTTP trigger. You can view the local project files in the Explorer. For more information about the files that are created, see Generated project files.

Run the function locally

Visual Studio Code integrates with Azure Functions Core tools to let you run this project on your local development computer before you publish to Azure.

  1. To call your function, press F5 to start the function app project. The Terminal panel displays the output from Core Tools. Your app starts in the Terminal panel. You can see the URL endpoint of your HTTP-triggered function running locally.

    Screenshot of the Local function Visual Studio Code output.

    If you have trouble running on Windows, make sure that the default terminal for Visual Studio Code isn't set to WSL Bash.

  2. With the Core Tools running, go to the Azure: Functions area. Under Functions, expand Local Project > Functions. Right-click (Windows) or Ctrl - click (macOS) the HttpExample function and choose Execute Function Now....

    Screenshot of execute function now from Visual Studio Code.

  3. In the Enter request body, press Enter to send a request message to your function.

  4. When the function executes locally and returns a response, a notification is raised in Visual Studio Code. Information about the function execution is shown in the Terminal panel.

  5. Press Ctrl + C to stop Core Tools and disconnect the debugger.

After checking that the function runs correctly on your local computer, it's time to use Visual Studio Code to publish the project directly to Azure.

Sign in to Azure

Before you can publish your app, you must sign in to Azure.

  1. If you aren't already signed in, choose the Azure icon in the Activity bar. Then in the Resources area, choose Sign in to Azure....

    Screenshot of the sign-in to Azure window within VS Code.

    If you're already signed in and can see your existing subscriptions, go to the next section. If you don't yet have an Azure account, choose Create and Azure Account.... Students can choose Create and Azure for Students Account....

  2. When prompted in the browser, choose your Azure account and sign in using your Azure account credentials. If you create a new account, you can sign in after your account is created.

  3. After you've successfully signed in, you can close the new browser window. The subscriptions that belong to your Azure account are displayed in the sidebar.

Create the function app in Azure

In this section, you create a function app and related resources in your Azure subscription.

  1. Choose the Azure icon in the Activity bar. Then in the Resources area, select the + icon and choose the Create Function App in Azure option.

    Create a resource in your Azure subscription

  2. Provide the following information at the prompts:

    Prompt Selection
    Select subscription Choose the subscription to use. You won't see this prompt when you have only one subscription visible under Resources.
    Enter a globally unique name for the function app Type a name that is valid in a URL path. The name you type is validated to make sure that it's unique in Azure Functions.
    Select a runtime stack Choose the language version on which you've been running locally.
    Select a location for new resources For better performance, choose a region near you.

    The extension shows the status of individual resources as they're being created in Azure in the Azure: Activity Log panel.

    Log of Azure resource creation

  3. When the creation is complete, the following Azure resources are created in your subscription. The resources are named based on your function app name:

    • A resource group, which is a logical container for related resources.
    • A standard Azure Storage account, which maintains state and other information about your projects.
    • A function app, which provides the environment for executing your function code. A function app lets you group functions as a logical unit for easier management, deployment, and sharing of resources within the same hosting plan.
    • An App Service plan, which defines the underlying host for your function app.
    • An Application Insights instance connected to the function app, which tracks usage of your functions in the app.

    A notification is displayed after your function app is created and the deployment package is applied.

    Tip

    By default, the Azure resources required by your function app are created based on the function app name you provide. By default, they're also created in the same new resource group with the function app. If you want to either customize the names of these resources or reuse existing resources, you need to publish the project with advanced create options instead.

Deploy the project to Azure

Important

Deploying to an existing function app always overwrites the contents of that app in Azure.

  1. Choose the Azure icon in the Activity bar, then in the Workspace area, select your project folder and select the Deploy... button.

    Deploy project from the Visual Studio Code workspace

  2. Select Deploy to Function App..., choose the function app you just created, and select Deploy.

  3. After deployment completes, select View Output to view the creation and deployment results, including the Azure resources that you created. If you miss the notification, select the bell icon in the lower right corner to see it again.

    Screenshot of the View Output window.

Run the function in Azure

  1. Back in the Resources area in the side bar, expand your subscription, your new function app, and Functions. Right-click (Windows) or Ctrl - click (macOS) the HttpExample function and choose Execute Function Now....

    Screenshot of executing function in Azure from Visual Studio Code.

  2. In Enter request body you see the request message body value of { "name": "Azure" }. Press Enter to send this request message to your function.

  3. When the function executes in Azure and returns a response, a notification is raised in Visual Studio Code.

Clean up resources

When you continue to the next step and add an Azure Storage queue binding to your function, you'll need to keep all your resources in place to build on what you've already done.

Otherwise, you can use the following steps to delete the function app and its related resources to avoid incurring any further costs.

  1. In Visual Studio Code, press F1 to open the command palette. In the command palette, search for and select Azure: Open in portal.

  2. Choose your function app and press Enter. The function app page opens in the Azure portal.

  3. In the Overview tab, select the named link next to Resource group.

    Screenshot of select the resource group to delete from the function app page.

  4. On the Resource group page, review the list of included resources, and verify that they're the ones you want to delete.

  5. In the Resource group page, review the list of included resources, and verify that they are the ones you want to delete.

  6. Select Delete resource group, and follow the instructions.

    Deletion may take a couple of minutes. When it's done, a notification appears for a few seconds. You can also select the bell icon at the top of the page to view the notification.

For more information about Functions costs, see Estimating Consumption plan costs.

Next steps

You have used Visual Studio Code to create a function app with a simple HTTP-triggered function. In the next article, you expand that function by connecting to either Azure Cosmos DB or Azure Queue Storage. To learn more about connecting to other Azure services, see Add bindings to an existing function in Azure Functions.