Default Sidekiq Redis configuration in Rails app - ruby-on-rails

Question

I'm trying to understand the Redis & Sidekiq configuration in a Passenger+Rails app and have run into some lack of understanding. I start the redis server independently of my rails app, while Sidekiq is a gem in my Rails app. I start it likewise: (no sidekiq.yml file needed for me)
bundle exec sidekiq
Following is my sidekiq.rb initializer:
require 'sidekiq'
require 'sidekiq-status'
Sidekiq.configure_client do |config|
config.client_middleware do |chain|
chain.add Sidekiq::Status::ClientMiddleware
end
end
Sidekiq.configure_server do |config|
config.server_middleware do |chain|
chain.add Sidekiq::Status::ServerMiddleware, expiration: 30.minutes
end
config.client_middleware do |chain|
chain.add Sidekiq::Status::ClientMiddleware
end
end
I went through some library classes, but to no avail.
I want to understand where does Sidekiq configure it's Redis server details. It defaults to localhost:6379, but I am not quite sure how.
Also, if I wish to use Memcached in future, how can I change that?

Answer 1

From sidekiq docs:
By default, Sidekiq tries to connect to Redis at localhost:6379
https://github.com/mperham/sidekiq/wiki/Using-Redis
You can change the port in the initializer:
Sidekiq.configure_server do |config|
config.redis = { url: 'redis://redis.example.com:7372/12' }
end
From the looks of it sidekiq works only with redis
Sidekiq uses Redis to store all of its job and operational data.

Answer 2

Here is what I did from the other answer:
# frozen_string_literal: true
Sidekiq.configure_server do |config|
config.redis = {
url: ENV.fetch("SIDEKIQ_REDIS_URL", "redis://localhost:6379/1")
}
end