gitlab-org--gitlab-foss/app/controllers/import/github_controller.rb
Yorick Peterse 4dfe26cd8b
Rewrite the GitHub importer from scratch
Prior to this MR there were two GitHub related importers:

* Github::Import: the main importer used for GitHub projects
* Gitlab::GithubImport: importer that's somewhat confusingly used for
  importing Gitea projects (apparently they have a compatible API)

This MR renames the Gitea importer to Gitlab::LegacyGithubImport and
introduces a new GitHub importer in the Gitlab::GithubImport namespace.
This new GitHub importer uses Sidekiq for importing multiple resources
in parallel, though it also has the ability to import data sequentially
should this be necessary.

The new code is spread across the following directories:

* lib/gitlab/github_import: this directory contains most of the importer
  code such as the classes used for importing resources.
* app/workers/gitlab/github_import: this directory contains the Sidekiq
  workers, most of which simply use the code from the directory above.
* app/workers/concerns/gitlab/github_import: this directory provides a
  few modules that are included in every GitHub importer worker.

== Stages

The import work is divided into separate stages, with each stage
importing a specific set of data. Stages will schedule the work that
needs to be performed, followed by scheduling a job for the
"AdvanceStageWorker" worker. This worker will periodically check if all
work is completed and schedule the next stage if this is the case. If
work is not yet completed this worker will reschedule itself.

Using this approach we don't have to block threads by calling `sleep()`,
as doing so for large projects could block the thread from doing any
work for many hours.

== Retrying Work

Workers will reschedule themselves whenever necessary. For example,
hitting the GitHub API's rate limit will result in jobs rescheduling
themselves. These jobs are not processed until the rate limit has been
reset.

== User Lookups

Part of the importing process involves looking up user details in the
GitHub API so we can map them to GitLab users. The old importer used
an in-memory cache, but this obviously doesn't work when the work is
spread across different threads.

The new importer uses a Redis cache and makes sure we only perform
API/database calls if absolutely necessary.  Frequently used keys are
refreshed, and lookup misses are also cached; removing the need for
performing API/database calls if we know we don't have the data we're
looking for.

== Performance & Models

The new importer in various places uses raw INSERT statements (as
generated by `Gitlab::Database.bulk_insert`) instead of using Rails
models. This allows us to bypass any validations and callbacks,
drastically reducing the number of SQL queries and Gitaly RPC calls
necessary to import projects.

To ensure the code produces valid data the corresponding tests check if
the produced rows are valid according to the model validation rules.
2017-11-07 23:24:59 +01:00

114 lines
3.1 KiB
Ruby

class Import::GithubController < Import::BaseController
before_action :verify_import_enabled
before_action :provider_auth, only: [:status, :jobs, :create]
rescue_from Octokit::Unauthorized, with: :provider_unauthorized
def new
if logged_in_with_provider?
go_to_provider_for_permissions
elsif session[access_token_key]
redirect_to status_import_url
end
end
def callback
session[access_token_key] = client.get_token(params[:code])
redirect_to status_import_url
end
def personal_access_token
session[access_token_key] = params[:personal_access_token]
redirect_to status_import_url
end
def status
@repos = client.repos
@already_added_projects = current_user.created_projects.where(import_type: provider)
already_added_projects_names = @already_added_projects.pluck(:import_source)
@repos.reject! { |repo| already_added_projects_names.include? repo.full_name }
end
def jobs
jobs = current_user.created_projects.where(import_type: provider).to_json(only: [:id, :import_status])
render json: jobs
end
def create
@repo_id = params[:repo_id].to_i
repo = client.repo(@repo_id)
@project_name = params[:new_name].presence || repo.name
namespace_path = params[:target_namespace].presence || current_user.namespace_path
@target_namespace = find_or_create_namespace(namespace_path, current_user.namespace_path)
if can?(current_user, :create_projects, @target_namespace)
@project = Gitlab::LegacyGithubImport::ProjectCreator.new(repo, @project_name, @target_namespace, current_user, access_params, type: provider).execute
else
render 'unauthorized'
end
end
private
def client
@client ||= Gitlab::LegacyGithubImport::Client.new(session[access_token_key], client_options)
end
def verify_import_enabled
render_404 unless import_enabled?
end
def go_to_provider_for_permissions
redirect_to client.authorize_url(callback_import_url)
end
def import_enabled?
__send__("#{provider}_import_enabled?") # rubocop:disable GitlabSecurity/PublicSend
end
def new_import_url
public_send("new_import_#{provider}_url") # rubocop:disable GitlabSecurity/PublicSend
end
def status_import_url
public_send("status_import_#{provider}_url") # rubocop:disable GitlabSecurity/PublicSend
end
def callback_import_url
public_send("callback_import_#{provider}_url") # rubocop:disable GitlabSecurity/PublicSend
end
def provider_unauthorized
session[access_token_key] = nil
redirect_to new_import_url,
alert: "Access denied to your #{Gitlab::ImportSources.title(provider.to_s)} account."
end
def access_token_key
:"#{provider}_access_token"
end
def access_params
{ github_access_token: session[access_token_key] }
end
# The following methods are overriden in subclasses
def provider
:github
end
def logged_in_with_provider?
current_user.identities.exists?(provider: provider)
end
def provider_auth
if session[access_token_key].blank?
go_to_provider_for_permissions
end
end
def client_options
{}
end
end