Katello Repository STI refactoring

John_Mitsch · March 15, 2017, 6:50pm

Hello all,

I wanted to share the plan for refactoring the Katello Repositories model
and get some feedback.

We have been wanting to break up repositories for some time. The
repositories table has a field "content_type", which is used to handle yum,
file, docker, ostree, and puppet repos. In addition to this, there is a
"Content View Puppet Environment" model, which inherits repository methods.
[1]

Some reasons to refactor repositories are:

The repository model is large and monolithic
Multiple exceptions have to be made for different content_types i.e [2]
Its easy to introduce bugs in this area
the complexity is blocking or making it harder to design new features
around repositories
Its the first step to implementing content type plugins - original design
here [3]

The plan is to use Single Table Inheritance on the repositories table, and
move the content_type column to the type column. Each content type will be
its own class and can have its own methods.

The API will likely stay the same or have minimal changes, The rabl files
would just need updating. Any additional API changes can happen after the
refactoring (with proper deprecation warnings)

This would be broken into small changes, which will look something like
this:

add STI to repositories model, but keep old logic
setup classes for each content type
remove content_type field and update logic that uses that field to know
use type field
move content based on functionality (in individual commits)
remove content view puppet environment and use "puppet" type repository
in its place

Let me know if you have any questions, looking forward to hearing
everyone's opinions.

[1]

github.com

Katello/katello/blob/master/app/models/katello/content_view_puppet_environment.rb#L6


module Katello
class ContentViewPuppetEnvironment < Katello::Model
  include ForemanTasks::Concerns::ActionSubject
  include Glue::Pulp::Repo if SETTINGS[:katello][:use_pulp]
  include Glue if SETTINGS[:katello][:use_pulp]


  belongs_to :environment, :class_name => "Katello::KTEnvironment",
                           :inverse_of => :content_view_puppet_environments
  belongs_to :content_view_version, :class_name => "Katello::ContentViewVersion",
                                    :inverse_of => :content_view_puppet_environments


  has_one :content_view, :through => :content_view_version, :class_name => "Katello::ContentView"


  belongs_to :puppet_environment, :class_name => "Environment",
                                  :inverse_of => :content_view_puppet_environment, :dependent => :destroy

[2]

github.com

Katello/katello/blob/937ca0da561347f94a22aae87aa52ab345eb1238/app/models/katello/glue/pulp/repo.rb#L154-L175


case self.content_type
when Repository::YUM_TYPE
  Runcible::Models::YumImporter.new(yum_importer_values(capsule))
when Repository::FILE_TYPE
  Runcible::Models::IsoImporter.new(importer_ssl_options(capsule).merge(:feed => importer_feed_url(capsule)))
when Repository::PUPPET_TYPE
  options = {:feed => importer_feed_url(capsule)}
  Runcible::Models::PuppetImporter.new(importer_ssl_options(capsule).merge(options))
when Repository::DOCKER_TYPE
  options = {}
  options[:upstream_name] = capsule.default_capsule? ? self.docker_upstream_name : self.container_repository_name
  options[:feed] = docker_feed_url(capsule)
  options[:enable_v1] = false
  Runcible::Models::DockerImporter.new(importer_ssl_options(capsule).merge(options))
when Repository::OSTREE_TYPE
  options = importer_ssl_options(capsule)


  options[:feed] = self.importer_feed_url(capsule)
  Runcible::Models::OstreeImporter.new(options)
else

This file has been truncated. show original

[3] ContentPlugins - Katello - Foreman

Thanks,
John Mitsch
Red Hat Engineering
(860)-967-7285
irc: jomitsch