> ## Documentation Index
> Fetch the complete documentation index at: https://upstash.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Supabase Functions

<Snippet file="redis/start-redis-snippet.mdx" />

The below is an example for a Redis counter that stores a
[hash](https://redis.io/commands/hincrby/) of Supabase function invocation count
per region.

## Redis database setup

Create a Redis database using the
[Upstash Console](https://console.upstash.com/) or
[Upstash CLI](https://github.com/upstash/cli).

Select the `Global` type to minimize the latency from all edge locations. Copy
the `UPSTASH_REDIS_REST_URL` and `UPSTASH_REDIS_REST_TOKEN` to your .env file.

You'll find them under **Details > REST API > .env**.

```shell theme={"system"}
cp supabase/functions/upstash-redis-counter/.env.example supabase/functions/upstash-redis-counter/.env
```

## Code

Make sure you have the latest version of the
[Supabase CLI installed](https://supabase.com/docs/guides/cli#installation).

Create a new function in your project:

```shell theme={"system"}
supabase functions new upstash-redis-counter
```

And add the code to the `index.ts` file:

```ts index.ts theme={"system"}
import { serve } from "https://deno.land/std@0.177.0/http/server.ts";
import { Redis } from "https://deno.land/x/upstash_redis@v1.19.3/mod.ts";
console.log(`Function "upstash-redis-counter" up and running!`);
serve(async (_req) => {
  try {
    const redis = new Redis({
      url: Deno.env.get("UPSTASH_REDIS_REST_URL")!,
      token: Deno.env.get("UPSTASH_REDIS_REST_TOKEN")!,
    });
    const deno_region = Deno.env.get("DENO_REGION");
    if (deno_region) {
      // Increment region counter
      await redis.hincrby("supa-edge-counter", deno_region, 1);
    } else {
      // Increment localhost counter
      await redis.hincrby("supa-edge-counter", "localhost", 1);
    }
    // Get all values
    const counterHash: Record<string, number> | null = await redis.hgetall(
      "supa-edge-counter"
    );
    const counters = Object.entries(counterHash!)
      .sort(([, a], [, b]) => b - a) // sort desc
      .reduce(
        (r, [k, v]) => ({
          total: r.total + v,
          regions: { ...r.regions, [k]: v },
        }),
        {
          total: 0,
          regions: {},
        }
      );
    return new Response(JSON.stringify({ counters }), { status: 200 });
  } catch (error) {
    return new Response(JSON.stringify({ error: error.message }), {
      status: 200,
    });
  }
});
```

## Run locally

```bash theme={"system"}
supabase start
supabase functions serve upstash-redis-counter --no-verify-jwt --env-file supabase/functions/upstash-redis-counter/.env
```

Navigate to [http://localhost:54321/functions/v1/upstash-redis-counter](http://localhost:54321/functions/v1/upstash-redis-counter).

## Deploy

```bash theme={"system"}
supabase functions deploy upstash-redis-counter --no-verify-jwt
supabase secrets set --env-file supabase/functions/upstash-redis-counter/.env
```