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/std@0.168.0/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.