What is Azure Function?

• Azure Function helps us to run a piece of code in the cloud.
• Azure Functions gets fired/triggered by an event.
• Trigger can be a QueueTrigger, an HttpTrigger, a BlobTrigger and so on.
• Let us take an example of an Azure function with an HttpTrigger. When it finds an Http endpoint, the azure function gets triggered and executes.

Features

• Serverless:
  • Abstraction of Servers: You don’t own a dedicated server.
  • Event-driven Scaling: It scales rapidly and dynamically. Pay for what you use.
  • Reduced DevOps: No maintenance required.
  • Focus on Business logic
• Accelerate Development:
  • It supports many programming languages like C#, Python, Java and JavaScript.
• Binding into various services:
  • Azure Functions can bind with other services like Azure Event Hub, SendGrid, Azure Storage

Let’s create an Azure Function

Step 1 – Navigate to Azure portal – https://portal.azure.com/

Step 2 – Login with your MSDN account.

Step 3 – Click “Create a resource”

Step 4 – Search Function App and press Enter.

Step 5 – Click “Create” to create an Azure Function

Step 6 – Fill all the required fields and Click “Review and Create”

Step 7 – Once it is reviewed. Click “Create”.

Step 8 – Open the created Function App.

Step 9 – In Functions tab, Click “New Function”

Step 10 – Choose Http trigger to execute Azure Functions

Step 11 – To create an Http Trigger. Click “Create”

Step 12 – Azure Function with Http Trigger has been created with the sample code. Click “Run”

Step 13 – If the Http method is a POST method, then pass a JSON object in the Request body. An output is displayed in the Output tab with Status code 200 OK.

Step 14 – Click “Get Function URL”. Copy the URL and paste it in the browser with “name” parameter in the URL. For example, “https://azurefunctionname.azurewebsites.net/api/functionName?code=SAAStoken&name=Azure”

Note: Use the below command to get the results in PowerShell.

Let me explain the code structure of an Http Trigger with the example above.

• C# sharp code contains asynchronous method that accepts two arguments.
  • An Http Request Message
  • Trace Writer – Used to log meaningful information. It can be viewed in the console and stored in Blob Storage.
• We check whether the URL has Http Request Message with “name” key.
  • If it has the key in the URL, then it returns Hello, with NAME
  • Else, we simply Create Response with Bad Request saying “Please pass a name on the query string or in the request body”

Summary

Deployed an Azure Function with HttpTrigger template. Tested the function app in Browser as well as with PowerShell command.

Nivedha Lakshmanan