Azure Functions Documentation

Azure Functions is a serverless, event-driven compute platform that allows you to build and deploy event-driven applications and services without managing infrastructure. This documentation provides comprehensive guidance on getting started with Azure Functions, understanding its core concepts, developing functions, and deploying them efficiently.

Key Concepts: Azure Functions enables you to write small pieces of code (functions) that respond to events. These events can be anything from HTTP requests, queue messages, database changes, to scheduled timers.

Getting Started

Begin your journey with Azure Functions by setting up your development environment and creating your first function.

Prerequisites

Create Your First Function

  1. Open Visual Studio Code and install the Azure Functions extension.
  2. Create a new Azure Functions project.
  3. Choose a template for your function (e.g., HTTP trigger).
  4. Write your function code and configure bindings.
  5. Run your function locally using Azure Functions Core Tools.

For detailed steps, refer to the tutorial for VS Code.

Core Concepts

Triggers

Triggers define how a function is invoked. Common triggers include:

  • HTTP Trigger: Invokes a function in response to an HTTP request.
  • Timer Trigger: Invokes a function on a schedule.
  • Queue Trigger: Invokes a function when a message is added to an Azure Storage Queue.
  • Blob Trigger: Invokes a function when a new or updated blob is detected in Azure Blob Storage.
  • Cosmos DB Trigger: Invokes a function in response to changes in a Cosmos DB container.

Bindings

Bindings simplify connecting your function to other Azure services and external data sources. They can be used for both input and output.

  • Input Bindings: Bring data into your function.
  • Output Bindings: Send data from your function to other services.

Example of an HTTP trigger with an output binding to send an HTTP response:


[
  {
    "type": "httpTrigger",
    "direction": "in",
    "name": "req",
    "methods": [
      "get",
      "post"
    ]
  },
  {
    "type": "http",
    "direction": "out",
    "name": "res"
  }
]

Runtime

Azure Functions supports multiple programming languages, including:

  • C#
  • JavaScript
  • TypeScript
  • Python
  • Java
  • PowerShell
  • Custom Handlers for other languages.

Development and Deployment

Local Development

Develop and test your functions locally using the Azure Functions Core Tools. This allows for a rapid development cycle before deploying to Azure.

Deployment Options

You can deploy your Azure Functions using various methods:

  • Azure CLI: Deploy from your local machine.
  • Visual Studio Code: Integrated deployment through the Azure Functions extension.
  • Azure DevOps / GitHub Actions: Implement CI/CD pipelines for automated deployments.
  • ARM Templates / Bicep: Infrastructure as Code for repeatable deployments.
Best Practice: For production applications, consider using deployment slots to test new versions before swapping them into production.

Monitoring and Troubleshooting

Monitor your function's performance and troubleshoot issues effectively using Azure Monitor, Application Insights, and logging.

  • Azure Monitor: Provides insights into your function's performance and health.
  • Application Insights: Offers advanced monitoring, diagnostics, and telemetry.
  • Logging: Implement robust logging within your functions to capture execution details.

Pricing

Azure Functions offers a consumption plan, premium plan, and dedicated (App Service) plan. The consumption plan is ideal for event-driven workloads where you pay only for the compute time you consume.

Learn more about Azure Functions pricing.

Next Steps