Rails 6 while running sidekiq database configuration does not specify adapter - ruby-on-rails

Question

Recently we started migrating our codebase from rails 5 to rails 6. Everything seems to work fine except sidekiq. Whenever we tried to run sidekiq in production mode it always throws an error database configuration does not specify adapter. I am pretty sure that we have mentioned an adapter in database.yml. Can someone please help to resolve this issue?
For reference
Rails 6.0.3.4
Sidekiq 6.1.2
Ruby 2.7.1p83
databsae.yml file
default: &default
adapter: postgresql
pool: <%= ENV['DATABASE_POOL'] %>
timeout: 5000
database: anajmandi
development:
primary:
<<: *default
url: <%= ENV['DATABASE_URL'] %>
multidb:
fallback: true
follower:
<<: *default
url: <%= ENV['DATABASE_SLAVE_URL'] %>
replica: true
multidb:
fallback: true
test:
<<: *default
database: db/test.sqlite3
production:
primary:
<<: *default
url: <%= ENV['DATABASE_URL'] %>
multidb:
fallback: true
follower:
<<: *default
url: <%= ENV['DATABASE_SLAVE_URL'] %>
replica: true
multidb:
fallback: true
and sidekiq.rb file
# typed: strict
if Rails.env.production?
# three unicorns = 3 connections
Sidekiq.configure_client do |config|
config.redis = { :size => 1 }
end
Sidekiq.configure_server do |config|
config.redis = { url: ENV['REDIS_URL'], size: 22 }
Rails.application.config.after_initialize do
Rails.logger.info("DB Connection Pool size for Sidekiq Server before disconnect is: #{ActiveRecord::Base.connection.pool.instance_variable_get('#size')}")
ActiveRecord::Base.connection_pool.disconnect!
ActiveSupport.on_load(:active_record) do
config = Rails.application.config.database_configuration[Rails.env]
config['reaping_frequency'] = ENV['DATABASE_REAP_FREQ'] || 10 # seconds
config['pool'] = ENV['WORKER_DB_POOL_SIZE'] || Sidekiq.options[:concurrency]
ActiveRecord::Base.establish_connection(config)
Rails.logger.info("DB Connection Pool size for Sidekiq Server is now: #{ActiveRecord::Base.connection.pool.instance_variable_get('#size')}")
end
end
end
end
and this is the error stack trace on running command bundle exec sidekiq -e production -C config/sidekiq.yml
DB Connection Pool size for Sidekiq Server before disconnect is: 5
database configuration does not specify adapter
/Users/yadusingla/.rvm/gems/ruby-2.7.1/gems/activerecord-6.0.3.4/lib/active_record/connection_adapters/connection_specification.rb:161:in `spec'
/Users/yadusingla/.rvm/gems/ruby-2.7.1/gems/activerecord-6.0.3.4/lib/active_record/connection_adapters/abstract/connection_pool.rb:1052:in `establish_connection'
/Users/yadusingla/.rvm/gems/ruby-2.7.1/gems/activerecord-6.0.3.4/lib/active_record/connection_handling.rb:51:in `establish_connection'
/Users/yadusingla/.rvm/gems/ruby-2.7.1/gems/activerecord-import-1.0.6/lib/activerecord-import/import.rb:250:in `establish_connection'
/Users/yadusingla/spars/procol-backend/config/initializers/sidekiq.rb:19:in `block (3 levels) in <top (required)>'
/Users/yadusingla/.rvm/gems/ruby-2.7.1/gems/activesupport-6.0.3.4/lib/active_support/lazy_load_hooks.rb:71:in `class_eval'
/Users/yadusingla/.rvm/gems/ruby-2.7.1/gems/activesupport-6.0.3.4/lib/active_support/lazy_load_hooks.rb:71:in `block in execute_hook'
/Users/yadusingla/.rvm/gems/ruby-2.7.1/gems/activesupport-6.0.3.4/lib/active_support/lazy_load_hooks.rb:61:in `with_execution_control'
/Users/yadusingla/.rvm/gems/ruby-2.7.1/gems/activesupport-6.0.3.4/lib/active_support/lazy_load_hooks.rb:66:in `execute_hook'
/Users/yadusingla/.rvm/gems/ruby-2.7.1/gems/activesupport-6.0.3.4/lib/active_support/lazy_load_hooks.rb:43:in `block in on_load'
/Users/yadusingla/.rvm/gems/ruby-2.7.1/gems/activesupport-6.0.3.4/lib/active_support/lazy_load_hooks.rb:42:in `each'
/Users/yadusingla/.rvm/gems/ruby-2.7.1/gems/activesupport-6.0.3.4/lib/active_support/lazy_load_hooks.rb:42:in `on_load'

Answer 1

Here I am using a 3-tier configuration, so for 3 tier configuration initializer isn't correctly defined. If we select configurations by environment variable then we'll get two, both primary and follower. Rails don't know which one to access so the app has to select the right one.
Change config = Rails.application.config.database_configuration[Rails.env] to
self.configurations = Rails.application.config.database_configuration
config = configurations.configs_for(env_name: Rails.env, spec_name: "primary").config
Refer to this link https://github.com/rails/rails/issues/40640