debian-mirror-gitlab/app/models/preloaders/environments/deployment_preloader.rb
2022-10-11 01:57:18 +05:30

53 lines
2.1 KiB
Ruby

# frozen_string_literal: true
module Preloaders
module Environments
# This class is to batch-load deployments of multiple environments.
# The deployments to batch-load are fetched using UNION of N selects in a single query instead of default scoping with `IN (environment_id1, environment_id2 ...)`.
# See https://gitlab.com/gitlab-org/gitlab/-/issues/345672#note_761852224 for more details.
class DeploymentPreloader
attr_reader :environments
def initialize(environments)
@environments = environments
end
def execute_with_union(association_name, association_attributes)
load_deployment_association(association_name, association_attributes)
end
private
def load_deployment_association(association_name, association_attributes)
return unless environments.present?
# Not using Gitlab::SQL::Union as `order_by` in the SQL constructed is ignored.
# See:
# 1) https://gitlab.com/gitlab-org/gitlab/-/blob/master/lib/gitlab/sql/union.rb#L7
# 2) https://gitlab.com/gitlab-org/gitlab/-/issues/353966#note_860928647
union_sql = environments.map do |environment|
"(#{environment.association(association_name).scope.to_sql})"
end.join(' UNION ')
deployments = Deployment
.from("(#{union_sql}) #{::Deployment.table_name}")
.preload(association_attributes)
deployments_by_environment_id = deployments.index_by(&:environment_id)
environments.each do |environment|
associated_deployment = deployments_by_environment_id[environment.id]
environment.association(association_name).target = associated_deployment
environment.association(association_name).loaded!
next unless associated_deployment
# `last?` in DeploymentEntity requires this environment to be loaded
associated_deployment.association(:environment).target = environment
associated_deployment.association(:environment).loaded!
end
end
end
end
end