Remove inline background jobs

This isn't working correctly, as internal ActiveStorage Jobs are not run
correctly. While we could configure:

  Rails.application.config.active_job.queue_adapter = :inline

This still doesn't seem to run all jobs inline, for example the purge
jobs are never executed resulting in old attachments left in storage.

app/jobs/application_job.rb

@@ -5,9 +5,4 @@ class ApplicationJob < ActiveJob::Base # :nodoc:
   # Most jobs are safe to ignore if the underlying records are no longer
   # available
   discard_on ActiveJob::DeserializationError
-
-  def self.perform_later(*args)
-    return super unless AlaveteliConfiguration.background_jobs == 'inline'
-    perform_now(*args)
-  end
 end

config/general.yml-example

@@ -1304,19 +1304,3 @@ SURVEY_URL: ''
 #
 # ---
 USER_SIGN_IN_ACTIVITY_RETENTION_DAYS: 0
-
-# Background jobs are processed by Rails' ActiveJob using Sidekiq. There are
-# various ways to run Sidekiq depending to server resources and technical
-# knowledge in order to run and maintain a Redis server.
-#
-# Can either be set to:
-# - 'inline' to process jobs within the web application process, this was the
-#   default option up until Alaveteli 0.42 and doesn't require Redis to be.
-#   installed. Due to issues with requests with web requests timing out this has
-#   been superseded by the other options.
-# - 'server' to process job by a server running as a system daemon.
-#
-# BACKGROUND_JOBS – String (default: 'server')
-#
-# ---
-BACKGROUND_JOBS: 'server'

config/test.yml

@@ -120,5 +120,3 @@ MAX_REQUESTS_PER_USER_PER_DAY: 2
 SKIP_ADMIN_AUTH: true
 
 UTILITY_SEARCH_PATH: []
-
-BACKGROUND_JOBS: 'server'

lib/configuration.rb

@@ -21,7 +21,6 @@ module AlaveteliConfiguration
       ADMIN_USERNAME: '',
       AUTHORITY_MUST_RESPOND: true,
       AVAILABLE_LOCALES: 'en',
-      BACKGROUND_JOBS: 'server',
       BLACKHOLE_PREFIX: 'do-not-reply-to-this-address',
       BLOCK_RATE_LIMITED_IPS: false,
       BLOCK_RESTRICTED_COUNTRY_IPS: false,
@@ -144,12 +143,6 @@ def self.get(key, default)
     value || MySociety::Config.get(key, default)
   end
 
-  def self.background_jobs
-    value = get('BACKGROUND_JOBS', DEFAULTS[:BACKGROUND_JOBS])
-    return value if %w[inline server].include?(value)
-    raise 'Unknown value for BACKGROUND_JOBS. Please check config/general.yml'
-  end
-
   def self.method_missing(name)
     key = name.to_s.upcase
     if DEFAULTS.key?(key.to_sym)

lib/tasks/config_files.rake

@@ -68,8 +68,7 @@ namespace :config_files do
       {
         path: '/etc/systemd/system',
         name: 'sidekiq.service',
-        template: 'config/sidekiq.service.example',
-        condition: -> { AlaveteliConfiguration.background_jobs == 'server' }
+        template: 'config/sidekiq.service.example'
       }
     ]
   end