Supabase Edge Functions

Step-by-Step Guide to Using Edge Functions in Supabase and Scheduling Them with Cron Jobs

Edge Functions in Supabase allow you to deploy server-side logic that runs on the edge, enabling fast and scalable operations. Here’s how you can create and deploy edge functions and schedule them with cron jobs:

1- Install Supabase CLI:

Download and install the Supabase CLI. This will be used to manage your project and deploy edge functions.

Install via npm:

npm install -g supabase

Authenticate with Supabase:

supabase login

Initialize a Supabase Project Locally:

Navigate to your project directory in the terminal.

Run:

supabase init

2. Create an Edge Function

Generate a New Function:

Use the CLI to generate a new edge function:

supabase functions new my-function

Replace my-function with the name of your function.

Write Your Function Logic:

Navigate to the functions/my-function/index.ts file.

Add your logic, for example:

javascript

`import { serve } from 'https://deno.land/[email protected]/http/server.ts';

serve(async (req) => {

return new Response('Hello, world!', {

headers: { 'Content-Type': 'text/plain' },

});

});`

Test Locally:

Start the function locally:

supabase functions serve my-function

Access the function at http://localhost:54321/functions/v1/my-function.

Deploy the Function:

Deploy your function to Supabase:

supabase functions deploy my-function

For this you must have Docker installed, and it must be open!

1. Test the Deployed Function
   Get the Function URL:

In the Supabase dashboard, navigate to Functions > my-function.

Copy the deployed function's URL.

Call the Function:

Use tools like curl, Postman, or JavaScript fetch to test the deployed function:

curl https://your-project-id.supabase.co/functions/v1/my-function

4. Schedule the Function with Cron Jobs

Install and Enable pg_cron in Supabase

Access Your Supabase Project:

Log in to your Supabase dashboard and open your project.

Enable pg_cron Extension:

Go to Database > Extensions.

Search for pg_cron and enable it by clicking the toggle.

Verify Installation:

Open the SQL Editor and run:

SELECT * FROM pg_available_extensions WHERE name = 'pg_cron';

Add a Postgres Function to Call the Edge Function

You need to create a PostgreSQL function that calls your Supabase Edge Function using HTTP.

Create the Postgres Function:

In the SQL Editor, write and execute:

`CREATE OR REPLACE FUNCTION call_edge_function()

RETURNS void AS $$

DECLARE

response jsonb;

BEGIN

-- Make an HTTP request to the Edge Function

SELECT INTO response

http_post(

'https://your-project-id.supabase.co/functions/v1/my-function', -- Replace with your Edge Function URL

'{}', -- Optional JSON payload (adjust as needed)

'Authorization=Bearer your-anon-key; Content-Type=application/json' -- Replace with your Supabase anon key

);

-- Optionally log the response (for debugging)

RAISE NOTICE 'Response: %', response;

END;

$$ LANGUAGE plpgsql;`

Replace:

your-project-id with your Supabase project ID.

your-anon-key with your Supabase anon key (available in the dashboard under Settings > API).

Test the Postgres Function:

Call the function manually to ensure it works:

SELECT call_edge_function();

Check the output for any errors.

1. Schedule the Function with pg_cron
   Create a Cron Job:

In the SQL Editor, write and execute:

SELECT cron.schedule(

'call_edge_function_job', -- Unique name for the job

'0 * * * *', -- Cron expression (e.g., every hour)

$$ SELECT call_edge_function(); $$

);

Replace the cron expression with your desired schedule. For example:

Every minute: * * * * *

Every hour: 0 * * * *

Every day at midnight: 0 0 * * *

List Scheduled Jobs:

Verify the job was created:

SELECT * FROM cron.job;

Remove or Update a Cron Job:

To remove a job:

SELECT cron.unschedule('call_edge_function_job');

By following these steps, you’ll have a fully functional edge function deployed on Supabase and scheduled with a cron job to run at your desired intervals.