debian-mirror-gitlab/lib/gitlab/issuables_count_for_state.rb
2021-11-11 11:23:49 +05:30

153 lines
4.4 KiB
Ruby

# frozen_string_literal: true
module Gitlab
# Class for counting and caching the number of issuables per state.
class IssuablesCountForState
# The name of the Gitlab::SafeRequestStore cache key.
CACHE_KEY = :issuables_count_for_state
# The expiration time for the Rails cache.
CACHE_EXPIRES_IN = 1.hour
THRESHOLD = 1000
# The state values that can be safely casted to a Symbol.
STATES = %w[opened closed merged all].freeze
attr_reader :project, :finder
def self.declarative_policy_class
'IssuablePolicy'
end
# finder - The finder class to use for retrieving the issuables.
# fast_fail - restrict counting to a shorter period, degrading gracefully on
# failure
def initialize(finder, project = nil, fast_fail: false, store_in_redis_cache: false)
@finder = finder
@project = project
@fast_fail = fast_fail
@cache = Gitlab::SafeRequestStore[CACHE_KEY] ||= initialize_cache
@store_in_redis_cache = store_in_redis_cache
end
def for_state_or_opened(state = nil)
self[state || :opened]
end
def fast_fail?
!!@fast_fail
end
# Define method for each state
STATES.each do |state|
define_method(state) { self[state] }
end
# Returns the count for the given state.
#
# state - The name of the state as either a String or a Symbol.
#
# Returns an Integer.
def [](state)
state = state.to_sym if cast_state_to_symbol?(state)
cache_for_finder[state] || 0
end
private
def cache_for_finder
cached_counts = Rails.cache.read(redis_cache_key, cache_options) if cache_issues_count?
cached_counts ||= @cache[finder]
return cached_counts if cached_counts.empty?
if cache_issues_count? && cached_counts.values.all? { |count| count >= THRESHOLD }
Rails.cache.write(redis_cache_key, cached_counts, cache_options)
end
cached_counts
end
def cast_state_to_symbol?(state)
state.is_a?(String) && STATES.include?(state)
end
def initialize_cache
Hash.new { |hash, finder| hash[finder] = perform_count(finder) }
end
def perform_count(finder)
return finder.count_by_state unless fast_fail?
fast_count_by_state_attempt!
# Determining counts when referring to issuable titles or descriptions can
# be very expensive, and involve the database reading gigabytes of data
# for a relatively minor piece of functionality. This may slow index pages
# by seconds in the best case, or lead to a statement timeout in the worst
# case.
#
# In time, we may be able to use elasticsearch or postgresql tsv columns
# to perform the calculation more efficiently. Until then, use a shorter
# timeout and return -1 as a sentinel value if it is triggered
begin
ApplicationRecord.with_fast_read_statement_timeout do
finder.count_by_state
end
rescue ActiveRecord::QueryCanceled => err
fast_count_by_state_failure!
Gitlab::ErrorTracking.track_exception(
err,
params: finder.params,
current_user_id: finder.current_user&.id,
issue_url: 'https://gitlab.com/gitlab-org/gitlab/-/issues/249180'
)
Hash.new(-1)
end
end
def fast_count_by_state_attempt!
Gitlab::Metrics.counter(
:gitlab_issuable_fast_count_by_state_total,
"Count of total calls to IssuableFinder#count_by_state with fast failure"
).increment
end
def fast_count_by_state_failure!
Gitlab::Metrics.counter(
:gitlab_issuable_fast_count_by_state_failures_total,
"Count of failed calls to IssuableFinder#count_by_state with fast failure"
).increment
end
def cache_issues_count?
@store_in_redis_cache &&
finder.instance_of?(IssuesFinder) &&
parent_group.present? &&
!params_include_filters?
end
def parent_group
finder.params.group
end
def redis_cache_key
['group', parent_group&.id, 'issues']
end
def cache_options
{ expires_in: CACHE_EXPIRES_IN }
end
def params_include_filters?
non_filtering_params = %i[
scope state sort group_id include_subgroups
attempt_group_search_optimizations non_archived issue_types
]
finder.params.except(*non_filtering_params).values.any?
end
end
end