MSDN Documentation

Step 1: Create a New Azure Functions Project

Open Visual Studio Code and navigate to the Azure extension. Click on the "Create New Project..." button. Choose a folder for your project, select "Azure Functions" as the project type, and choose a runtime (e.g., Node.js).

You'll be prompted to select a template for your first function. For this tutorial, we'll choose "HTTP trigger" to create a function that can be invoked via an HTTP request.

Project Structure: Your project will have a structure similar to this:

your-function-app/
├── HttpTrigger/
│   ├── function.json
│   └── index.js
├── host.json
├── local.settings.json
└── package.json
                    

function.json defines the trigger and bindings for your function.

index.js (or your chosen language equivalent) contains the actual code for your function.

Step 2: Write Your Function Code

Let's create a simple HTTP-triggered function that returns a greeting. Open HttpTrigger/index.js and replace its content with the following:

module.exports = async function (context, req) {
    context.log('JavaScript HTTP trigger function processed a request.');

    const name = (req.query.name || (req.body && req.body.name));
    const responseMessage = name
        ? 'Hello, ' + name + '. This HTTP triggered function executed successfully!'
        : 'This HTTP triggered function executed successfully. Pass a name in the query string or in the request body for a personalized response.';

    context.res = {
        // status: 200, /* Defaults to 200 */
        body: responseMessage
    };
};
                    

In this code:

• context.log: Used for logging.
• req: Represents the incoming HTTP request.
• req.query: Contains query parameters.
• req.body: Contains the request body (useful for POST requests).
• context.res: Used to set the HTTP response.

Step 3: Test Your Function Locally

Before deploying, it's crucial to test your function locally. Ensure Azure Functions Core Tools is installed and run the following command in your project's root directory:

func start
                    

This will start a local Functions host. You'll see output indicating the URL for your HTTP trigger. Typically, it will be something like http://localhost:7071/api/HttpTrigger.

Open your web browser or a tool like Postman and navigate to this URL. Try appending a name to the URL, like http://localhost:7071/api/HttpTrigger?name=World, to see the personalized response.

Step 4: Deploy to Azure

Once you're satisfied with the local testing, it's time to deploy. In Visual Studio Code, with the Azure Functions extension active, select your function app project and click the "Deploy to Function App..." button. You'll be prompted to:

• Select your Azure subscription.
• Choose to create a new function app or select an existing one.
• Provide a globally unique name for your new function app.
• Select a runtime stack (e.g., Node.js).
• Choose a region.

The extension will create the necessary Azure resources (Function App, Storage Account) and deploy your code.

Step 5: Test Your Deployed Function

After deployment, you can find the URL of your deployed function in the Azure portal or through the Azure extension in VS Code. Navigate to your Function App in the Azure portal, select the "HttpTrigger" function, and copy the "Function URL".

Test the URL in your browser, similar to how you tested it locally. For example:

https://your-function-app-name.azurewebsites.net/api/HttpTrigger?name=Azure
                    

You should receive the personalized greeting from your serverless function running in Azure.