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Netlify Functions and Netlify Edge Functions

Netlify Functions and Netlify Edge Functions

Create Netlify functions, use environment variables, install third party packages, pass data to functions and test locally and on live remote

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Serverless
4 minutes
Netlify edge-computing serverless

Summary

  • how to create a function file
  • how to save and use environment variables
  • how to install and use third party packages
  • how to run your functions locally and on live remote
  • how to pass data to netlify functions

Functions vs. Edge Functions

There are functions and there are edge functions. Both are serverless functions, with edge function being served from CDN server locations closest to the user ref.

  • Function can be created in TS, JS and Go; and are based on a Nodejs runtime. (Tip: the Node version can be configured from the dashborad or netlify.toml or .nvmrc)
  • Edge Functions on the other hand are based on a Deno runtime and can only be in TypeScript and JavaScript. .jsx, .tsx are also supported for SSR (server-side-handling)
  • There will be minor differences between the two function types as the code will need to be adjusted for that particular runtime. For example, module imports are done differently.

Function or Edge Function? Which one to choose? Personally, i always go with edge-functions because they’re simpler and i don’t have to worry about module formats. The only reason i would choose functions is if i wanted to write Go functions

netlify                                                                                       
├── edge-functions    <-- Directory for Edge Functions     
│   └── fetch_users.ts                                                                  
│   └── foo.js
│   └── bar.tsx 
│   └── baz.jsx  
└── functions         <-- Directory for Functions            
│   └── send_email.ts  <-- ES module if type:module in package.json, otherwise CommonJS                                                                     
│   └── send_email.mts <-- ES module  
│   └── send_email.cts <-- CommonJS module      
            

1# netlify.toml
2
3[build]
4	functions = "netlify/functions"
5  edge_functions = "my-custom-directory"
6
7[functions]
8  node_bundler = "esbuild"

1# .nvmrc
2lts/*

Creating a function

Creating both types of functions is the same, just the folder name changes. Creat a file with the relevant file extension (.ts/.mts/.cjs for Functions or .ts/.js/.tsx/.jsx for Edge Functions) in the relevant directory (inside BASE_DIR/netlify/functions for Functions or in BASE_DIR/netlify/edge-functions for Edge Functions)

The default directories are YOUR_BASE_DIRECTORY/netlify/edge-functions and YOUR_BASE_DIRECTORY/netlify/functions. You can change these defaults in netlify.toml or the Netlify dashboard

1# netlify.toml
2
3[build]
4  base = '/'
5	functions = "netlify/functions"
6  edge_functions = "my-custom-directory"
7
8[functions]
9  node_bundler = "esbuild"

Create the directory and the file

1mkdir -p netlify/edge-functions
2cd netlify/edge-functions
3
4touch testfunction.ts

Anatomy of a function

Install and use third party npm packages

Edge Functions support using npm modules inside your functions

1npm install @sendgrid/mail

Running the functions

In order to run the functions, we need to install a bunch of packages. Node should already be installed

1npm install netlify-cli --global

If you’re using TypeScript and want type-safety inside your functions, install @netlify/edge-functions and/or @netlify/functions

1npm install @netlify/edge-functions
2npm install @netlify/functions

1# test locally 
2netlify dev

Environment Variables

You can set environment variables from the Netlify dashborad area.

netlify environment variables configuration

Note that environment variables declared in a Netlify configuration file (netlify.toml) are not available to functions. process.env vars are also not available. You would use Netlify.env.get() instead to use these variables inside your function

1export const OWM_API_KEY = Netlify.env.get("OPENWEATHER_API_KEY")

URLs and Paths

The default URLs for Netlify Functions are:

# Directory
YOUR_BASE_DIRECTORY/netlify/functions

# Local (Netlify Dev)
http://localhost:8888/.netlify/functions/<FUNCTION NAME>

# Deployed
https://<YOUR DOMAIN>/.netlify/functions/<FUNCTION NAME>

and for Netlify Edge Functions:

# Directory
YOUR_BASE_DIRECTORY/netlify/edge-functions

# Local (Netlify Dev)
http://localhost:8888/<FUNCTION PATH>

# Deployed
yoursitename.netlify.app/<FUNCTION NAME>

Code samples

  • mawsome is using Netlify Edge Functions to get weather data from the OpenWeatherMap API. It handles being passed a city name and gets weather data for that city.
  • tmdb-movies is using Netlify Edge Functions to get movie data from the TMDB API

Troubleshooting

Returning HTML instead of expected JSON

Check the URL for the function. It is most likely not hitting the right URL and the function is not being called.

404 not found

Check if you are actually returning a response inside your function

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