Upstash Redis

A Redis counter example that stores a hash of function invocation count per region. Find the code on GitHub.

Redis database setup#

Create a Redis database using the Upstash Console or 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.

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.

Create a new function in your project:

supabase functions new upstash-redis-counter

And add the code to the index.ts file:

index.ts

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#

supabase start
supabase functions serve --no-verify-jwt --env-file supabase/functions/upstash-redis-counter/.env

Navigate to http://localhost:54321/functions/v1/upstash-redis-counter.

Deploy#

supabase functions deploy upstash-redis-counter --no-verify-jwt
supabase secrets set --env-file supabase/functions/upstash-redis-counter/.env

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