gitlab-org--gitlab-foss/app/models/concerns/atomic_internal_id.rb
Kamil Trzciński fb07863693 Rewind IID on Ci::Pipelines
If no pipeline is created we currently have IID gap.
This is due to fact that we generate IID not on save,
but rather ahead of time. This results, us,
losing IIDs.
2019-04-16 11:22:23 +02:00

72 lines
2.5 KiB
Ruby

# frozen_string_literal: true
# Include atomic internal id generation scheme for a model
#
# This allows us to atomically generate internal ids that are
# unique within a given scope.
#
# For example, let's generate internal ids for Issue per Project:
# ```
# class Issue < ApplicationRecord
# has_internal_id :iid, scope: :project, init: ->(s) { s.project.issues.maximum(:iid) }
# end
# ```
#
# This generates unique internal ids per project for newly created issues.
# The generated internal id is saved in the `iid` attribute of `Issue`.
#
# This concern uses InternalId records to facilitate atomicity.
# In the absence of a record for the given scope, one will be created automatically.
# In this situation, the `init` block is called to calculate the initial value.
# In the example above, we calculate the maximum `iid` of all issues
# within the given project.
#
# Note that a model may have more than one internal id associated with possibly
# different scopes.
module AtomicInternalId
extend ActiveSupport::Concern
class_methods do
def has_internal_id(column, scope:, init:, presence: true) # rubocop:disable Naming/PredicateName
# We require init here to retain the ability to recalculate in the absence of a
# InternaLId record (we may delete records in `internal_ids` for example).
raise "has_internal_id requires a init block, none given." unless init
before_validation :"ensure_#{scope}_#{column}!", on: :create
validates column, presence: presence
define_method("ensure_#{scope}_#{column}!") do
scope_value = association(scope).reader
value = read_attribute(column)
return value unless scope_value
scope_attrs = { scope_value.class.table_name.singularize.to_sym => scope_value }
usage = self.class.table_name.to_sym
if value.present?
InternalId.track_greatest(self, scope_attrs, usage, value, init)
else
value = InternalId.generate_next(self, scope_attrs, usage, init)
write_attribute(column, value)
end
value
end
define_method("reset_#{scope}_#{column}") do
if value = read_attribute(column)
scope_value = association(scope).reader
scope_attrs = { scope_value.class.table_name.singularize.to_sym => scope_value }
usage = self.class.table_name.to_sym
if InternalId.reset(self, scope_attrs, usage, value)
write_attribute(column, nil)
end
end
read_attribute(column)
end
end
end
end