Issue with updating sidekiq on heroku

[iduuck]

Ruby version: 2.6.6p146
Rails version: 6.0.3.4
Sidekiq: 4.2.5

Previously the bug was this one → redis/redis-rb#974

Downgrading both redis-rb (as seen in the linked issue) and sidekiq fixed all issues for me.

My Procfile looks like this:

web: bundle exec rails server -p $PORT
worker: bundle exec sidekiq
release: bundle exec rails db:migrate

Initializer

Actually not an initializer at all.

# frozen_string_literal: true

cron_schedule_file = 'config/schedule.yml'

if File.exist?(cron_schedule_file) && Sidekiq.server?
  Sidekiq::Cron::Job.load_from_hash YAML.load_file(cron_schedule_file)
end

Sidekiq.yml

N/A

Backtrace

2021-01-19T11:23:14.357675+00:00 app[worker.1]: pid=4 tid=gt8pexh84 ERROR: heartbeat: ERR unknown command `exists?`, with args beginning with: `worker.1:4:43f253dd9864`,
2021-01-19T11:23:19.362008+00:00 app[worker.1]: pid=4 tid=gt8pexh84 ERROR: heartbeat: ERR unknown command `exists?`, with args beginning with: `worker.1:4:43f253dd9864`,
2021-01-19T11:23:24.368291+00:00 app[worker.1]: pid=4 tid=gt8pexh84 ERROR: heartbeat: ERR unknown command `exists?`, with args beginning with: `worker.1:4:43f253dd9864`,
2021-01-19T11:23:29.374600+00:00 app[worker.1]: pid=4 tid=gt8pexh84 ERROR: heartbeat: ERR unknown command `exists?`, with args beginning with: `worker.1:4:43f253dd9864`,

[iduuck]

Just had a look through closed issues, and found this one: #4779

So, I know that hiredis is not working with SSL, but the shown commit is only referencing a benchmark script, so this shouldn't be a problem.

Any idea if this could correlate with each other?

[mperham]

Did you read the 5.0 and 6.0 upgrade notes in the root of the repo? All you should need to do is bundle up sidekiq. That error indicates you were running a version of the redis gem which was out of sync with sidekiq.

[iduuck]

Actually my update wasn't from 5.0 to 6.0. Rather a minor version bump.