Azure Functions

Azure Functions is a serverless compute service that enables you to run code on-demand without explicitly provisioning or managing infrastructure. With Azure Functions, you can build applications by running code in response to events, orchestrating workflows, and integrating with other Azure services. You pay only for the time your code runs, and Azure automatically scales your application based on demand.

Key Concepts

Event-Driven Architecture

Azure Functions are designed around an event-driven paradigm. Your code, referred to as a "function," executes in response to a specific "trigger." Triggers can originate from a wide variety of Azure services and external sources, such as:

• HTTP Requests: Trigger functions via web requests.
• Timers: Execute functions on a schedule.
• Azure Service Events: Respond to changes in Azure Storage, Service Bus, Event Hubs, Cosmos DB, and more.
• Third-Party Services: Integrate with services like Twilio, SendGrid, and more.

Triggers and Bindings

Beyond the trigger that initiates a function execution, Azure Functions utilize bindings to connect your code to other Azure services and external data sources. Bindings simplify integration by reducing the amount of boilerplate code you need to write.

• Input Bindings: Fetch data from a service and make it available as parameters to your function.
• Output Bindings: Send data from your function to a service.

For example, you can use an input binding to automatically read a message from an Azure Queue Storage and an output binding to write a result to Azure Cosmos DB, all without writing explicit SDK code for these operations within your function.

Programming Model

Azure Functions support multiple programming languages, including:

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

Functions can be developed using the Azure portal for simple scenarios or locally using tools like Visual Studio Code with the Azure Functions extension, Visual Studio, or the Azure CLI for more complex development workflows.

Hosting Options

Azure Functions offers several hosting plans to suit different needs:

• Consumption Plan: The default serverless option. You pay per execution and resource consumption. Functions scale automatically and you're billed for compute time.
• Premium Plan: Offers pre-warmed instances, VNet connectivity, and longer run times without cold starts.
• Dedicated (App Service) Plan: Run Functions on the same infrastructure as App Service. You pay for the underlying VMs.
• Kubernetes: Deploy Functions to Azure Kubernetes Service (AKS) or other Kubernetes environments using the Azure Functions Kubernetes connector.