Deploy a function with Azion CLI

Create a function project from the terminal with Azion CLI, run it on your machine, and deploy it to a live domain.

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In this tutorial, you will build and deploy a function from the terminal with Azion CLI. You will save a personal token and create a project. Then you will write the handler, run it on your machine, and deploy it.

The Functions quickstart reaches the same result through Azion Console. This page is the terminal path, and it ends with the same three objects: a function, an instance, and the application that serves it.

Prerequisites

1. Save your personal token

The CLI authorizes every command with a personal token stored on your machine. To save it:

azion -t <your-token>

The token is stored locally, and the commands that follow authorize with it. You do not pass it again.

2. Create the project

azion init creates the project and its build configuration. To start it:

azion init

The command asks for a name, suggesting one you can accept:

? Your applications name: (affectionate-chaos)

Then it asks which preset to use. Select Javascript, the preset for a function written in plain JavaScript rather than a framework:

Shell
01? Choose a preset: [Use arrows to move, type to filter]
02> AI Studio
03 Angular
04 Astro
05 ...
06 Javascript

Then it asks which template to start from. Select Hello World:

Shell
01? Choose a template: [Use arrows to move, type to filter]
02> Hello World
03 HTMX Boilerplate
04 Simple Javascript Router Node
05 Simple Javascript Router
06 QStash EdgeFunction Scheduler
07 Upstash Geolocation
08 Upstash Rate Limit

It asks whether to install the project dependencies. Answer Y:

🤔 Do you want to install project dependencies? This may be required to generate initial configuration file (Y/n)

It asks whether to start a local development server. Answer N, because step 4 starts it:

🤔 Do you want to start a local development server? (y/N)

The project directory now holds the build configuration and the entrypoint the build reads.

3. Write the handler

Open index.js, the entrypoint the build reads by default, and replace its contents with an ES Modules handler:

JavaScript
01export default {
02 async fetch(request, env, ctx) {
03 return new Response('Hello World', {
04 headers: { 'content-type': 'text/plain' }
05 });
06 }
07};

The fetch method receives the request, the environment variables, and the execution context, and returns the response the client receives. This is the pattern Azion recommends.

4. Run the function locally

Before deploying, run the project on your machine and send it a request. To start the local server with azion dev:

azion dev

The command builds the project, then prints the address it serves on:

[Azion] [Server] › ✔ success Function running on port 0.0.0.0:3333, url: http://localhost:3333

From another terminal, request that address:

curl http://localhost:3333/

The handler answers with its response body:

Hello World

Stop the server with Ctrl+C once the response is correct.

5. Deploy the project

To deploy the project to Azion with azion deploy:

azion deploy

The command builds the project and creates the application and the function on your account. It instantiates the function and prints the domain that serves it. The domain has the format xxxxxxxxxx.map.azionedge.net.

Requesting that domain returns the same response you read locally:

curl https://xxxxxxxxxx.map.azionedge.net/
Hello World

The first deploy can take several minutes to answer from every location. An immediate request can fail before the configuration is in place. Wait and retry before diagnosing.

Next steps

Develop and test a function locallyRun the project on your machine and supply environment variables from a local file.How Functions worksWhat has to exist before a function runs on a request.JavaScript examplesHandlers to copy into the project as a starting point.Azion CLIEvery command the CLI accepts, and the flags for each one.