discourse/config/initializers/sidekiq.rb

require "sidekiq/pausable"

Sidekiq.configure_client do |config|
  config.redis = Discourse.sidekiq_redis_config
end

Sidekiq.configure_server do |config|
  config.redis = Discourse.sidekiq_redis_config

  config.server_middleware do |chain|
    chain.add Sidekiq::Pausable
    # ensure statistic middleware is included in case of a fork
    chain.add Sidekiq::Statistic::Middleware
  end
end

if Sidekiq.server?

  # warm up AR
  RailsMultisite::ConnectionManagement.each_connection do
    (ActiveRecord::Base.connection.tables - %w[schema_migrations]).each do |table|
      table.classify.constantize.first rescue nil
    end
  end

  Rails.application.config.after_initialize do
    require 'scheduler/scheduler'
    manager = Scheduler::Manager.new
    Scheduler::Manager.discover_schedules.each do |schedule|
      manager.ensure_schedule!(schedule)
    end
    Thread.new do
      while true
        begin
          manager.tick
        rescue => e
          # the show must go on
          Discourse.handle_job_exception(e, {message: "While ticking scheduling manager"})
        end
        sleep 1
      end
    end
  end
end

Sidekiq.logger.level = Logger::WARN

class SidekiqLogsterReporter < Sidekiq::ExceptionHandler::Logger
  def call(ex, context = {})

    return if Jobs::HandledExceptionWrapper === ex

    # Pass context to Logster
    fake_env = {}
    context.each do |key, value|
      Logster.add_to_env(fake_env, key, value)
    end

    text = "Job exception: #{ex}\n"
    if ex.backtrace
      Logster.add_to_env(fake_env, :backtrace, ex.backtrace)
    end

    Logster.add_to_env(fake_env, :current_hostname, Discourse.current_hostname)

    Thread.current[Logster::Logger::LOGSTER_ENV] = fake_env
    Logster.logger.error(text)
  rescue => e
    Logster.logger.fatal("Failed to log exception #{ex} #{hash}\nReason: #{e.class} #{e}\n#{e.backtrace.join("\n")}")
  ensure
    Thread.current[Logster::Logger::LOGSTER_ENV] = nil
  end
end

Sidekiq.error_handlers.clear
Sidekiq.error_handlers << SidekiqLogsterReporter.new