debian-mirror-gitlab/lib/gitlab/query_limiting/transaction.rb
2018-03-17 18:26:18 +05:30

77 lines
1.9 KiB
Ruby

module Gitlab
module QueryLimiting
class Transaction
THREAD_KEY = :__gitlab_query_counts_transaction
attr_accessor :count, :whitelisted
# The name of the action (e.g. `UsersController#show`) that is being
# executed.
attr_accessor :action
# The maximum number of SQL queries that can be executed in a request. For
# the sake of keeping things simple we hardcode this value here, it's not
# supposed to be changed very often anyway.
THRESHOLD = 100
# Error that is raised whenever exceeding the maximum number of queries.
ThresholdExceededError = Class.new(StandardError)
def self.current
Thread.current[THREAD_KEY]
end
# Starts a new transaction and returns it and the blocks' return value.
#
# Example:
#
# transaction, retval = Transaction.run do
# 10
# end
#
# retval # => 10
def self.run
transaction = new
Thread.current[THREAD_KEY] = transaction
[transaction, yield]
ensure
Thread.current[THREAD_KEY] = nil
end
def initialize
@action = nil
@count = 0
@whitelisted = false
end
# Sends a notification based on the number of executed SQL queries.
def act_upon_results
return unless threshold_exceeded?
error = ThresholdExceededError.new(error_message)
raise(error) if raise_error?
end
def increment
@count += 1 unless whitelisted
end
def raise_error?
Rails.env.test?
end
def threshold_exceeded?
count > THRESHOLD
end
def error_message
header = 'Too many SQL queries were executed'
header += " in #{action}" if action
"#{header}: a maximum of #{THRESHOLD} is allowed but #{count} SQL queries were executed"
end
end
end
end