Heroku crashes after Heroku Redis upgrade from Hobby to Premium 0

Problem

When I upgraded from the Heroku Redis Hobby plan to the Heroku Redis Premium 0 plan, Heroku kept crashing with an H10 error.

Cause

Redis 6 requires TLS to connect. However, Heroku manages requests from the router level to the application level involving Self Signed Certs. Turns out, Heroku terminates SSL at the router level and requests are forwarded from there to the application via HTTP while everything is behind Heroku's Firewall and security measures.

Links that helped track down the cause:

https://ogirginc.github.io/en/heroku-redis-ssl-error

How to enable TLS for Redis 6 on Sidekiq?

Solution

Customize the options passed into Redis so that tls.rejectUnauthorized is set to false.

const Queue = require('bull');
const redisUrlParse = require('redis-url-parse');

const REDIS_URL = process.env.REDIS_URL || 'redis://127.0.0.1:6379';
const redisUrlParsed = redisUrlParse(REDIS_URL);
const { host, port, password } = redisUrlParsed;
const bullOptions = REDIS_URL.includes('rediss://')
  ? {
      redis: {
        port: Number(port),
        host,
        password,
        tls: {
          rejectUnauthorized: false,
        },
      },
    }
  : REDIS_URL;

const workQueue = new Queue('work', bullOptions);