serverless/docs/providers/azure/guide/intro.md

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Azure - Introduction

The Serverless Framework helps you develop and deploy serverless applications using Azure Functions. It's a CLI that offers structure, automation and best practices out-of-the-box, allowing you to focus on building sophisticated, event- driven, serverless architectures, comprised of Functions and Events.

The Serverless Framework is different than other application frameworks because:

• It manages your code as well as your infrastructure
• It supports multiple languages (Node.js, Python, Java, and more)

Core Concepts

Here are the Framework's main concepts and how they pertain to Azure Functions…

Functions

A Function is an Azure Function. It's an independent unit of deployment, like a microservice. It's merely code, deployed in the cloud, that is most often written to perform a single job such as:

• Saving a user to the database
• Processing a file in a database
• Performing a scheduled task

You can perform multiple jobs in your code, but we don't recommend doing that without good reason. Separation of concerns is best and the Framework is designed to help you easily develop and deploy Functions, as well as manage lots of them.

Events

Anything that triggers an Azure Function to execute is regarded by the Framework as an Event. Events are platform events on Azure Functions such as:

• An HTTP Trigger (e.g., for a REST API)
• A scheduled timer (e.g., run every 5 minutes)
• A Service Bus Queue trigger (e.g. a workitem from another Function)
• An IoT/Event Hub message (e.g., a message from a device or service)
• A Webhook fires (e.g., Github project update)
• And more...

When you define an event for your Azure Function in the Serverless Framework, the Framework will automatically translate this into bindings needed for that event and configure your functions to listen to it.

Services

A Service is the Framework's unit of organization. You can think of it as a project file, though you can have multiple services for a single application. It's where you define your Functions, the Events that trigger them, and the Resources your Functions use, all in one file entitled serverless.yml (or serverless.json). It looks like this:

# serverless.yml

service: users

functions: # Your "Functions"
  usersCreate:
    events: # The "Events" that trigger this function
      - http: true
        x-azure-settings:
          name: req
          methods:
           - POST
          route: /users/create
  usersDelete:
    events:
      - http: true
        x-azure-settings:
          name: req
          methods:
           - DELETE
          route: /users/delete

When you deploy with the Framework by running serverless deploy, everything in serverless.yml is deployed at once.

Plugins

You can overwrite or extend the functionality of the Framework using Plugins. Every serverless.yml can contain a plugins: property, which features multiple plugins.

# serverless.yml

plugins:
  - serverless-plugin-identifier
  - serverless-another-plugin