Simplify how we create container registry resources

app/services/container_registry/create_repository_service.rb

-module ContainerRegistry
-  ##
-  # Service for creating a container repository.
-  #
-  # It is usually executed before registry authenticator returns
-  # a token for given request.
-  #
-  class CreateRepositoryService < BaseService
-    def execute(path)
-      @path = path
-
-      return if path.has_repository?
-
-      unless user_can_create? || legacy_trigger_can_create?
-        raise Gitlab::Access::AccessDeniedError
-      end
-
-      ContainerRepository.create_from_path(path)
-    end
-
-    private
-
-    def user_can_create?
-      can?(@current_user, :create_container_image, @path.repository_project)
-    end
-
-    ## TODO, remove it after removing legacy triggers.
-    #
-    def legacy_trigger_can_create?
-      @current_user.nil? && @project == @path.repository_project
-    end
-  end
-end

spec/services/container_registry/create_repository_service_spec.rb

-require 'spec_helper'
-
-describe ContainerRegistry::CreateRepositoryService, '#execute' do
-  let(:project) { create(:empty_project) }
-  let(:user) { create(:user) }
-
-  let(:path) do
-    ContainerRegistry::Path.new("#{project.full_path}/my/image")
-  end
-
-  let(:service) { described_class.new(project, user) }
-
-  before do
-    stub_container_registry_config(enabled: true)
-  end
-
-  context 'when repository is created by an user' do
-    context 'when user has no ability to create a repository' do
-      it 'does not create a new container repository' do
-        expect { service.execute(path) }
-          .to raise_error(Gitlab::Access::AccessDeniedError)
-          .and change { ContainerRepository.count }.by(0)
-      end
-    end
-
-    context 'when user has ability do create a repository' do
-      before do
-        project.add_developer(user)
-      end
-
-      context 'when repository already exists' do
-        before do
-          create(:container_repository, project: project, name: 'my/image')
-        end
-
-        it 'does not create container repository again' do
-          expect { service.execute(path) }
-            .to_not change { ContainerRepository.count }
-        end
-      end
-
-      context 'when repository does not exist yet' do
-        it 'creates a new container repository' do
-          expect { service.execute(path) }
-            .to change { project.container_repositories.count }.by(1)
-        end
-      end
-    end
-  end
-
-  context 'when repository is created by a legacy pipeline trigger' do
-    let(:user) { nil }
-
-    context 'when repository path matches authenticated project' do
-      it 'creates a new container repository' do
-        expect { service.execute(path) }
-          .to change { project.container_repositories.count }.by(1)
-      end
-    end
-
-    context 'when repository path does not match authenticated project' do
-      let(:private_project) { create(:empty_project, :private) }
-
-      let(:path) do
-        ContainerRegistry::Path.new("#{private_project.full_path}/my/image")
-      end
-
-      it 'does not create a new container repository' do
-        expect { service.execute(path) }
-          .to raise_error(Gitlab::Access::AccessDeniedError)
-          .and change { ContainerRepository.count }.by(0)
-      end
-    end
-  end
-end