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Diffstat (limited to 'lib/gitlab/query_limiting/transaction.rb')
-rw-r--r-- | lib/gitlab/query_limiting/transaction.rb | 83 |
1 files changed, 83 insertions, 0 deletions
diff --git a/lib/gitlab/query_limiting/transaction.rb b/lib/gitlab/query_limiting/transaction.rb new file mode 100644 index 00000000000..3cbafadb0d0 --- /dev/null +++ b/lib/gitlab/query_limiting/transaction.rb @@ -0,0 +1,83 @@ +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) + + if raise_error? + raise(error) + else + # Raven automatically logs to the Rails log if disabled, thus we don't + # need to manually log anything in case Sentry support is not enabled. + Raven.capture_exception(error) + end + 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 |