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| -rw-r--r-- | lib/gitlab/instrumentable.rb | 58 |
1 files changed, 58 insertions, 0 deletions
diff --git a/lib/gitlab/instrumentable.rb b/lib/gitlab/instrumentable.rb new file mode 100644 index 00000000000..1d7e7b0f2df --- /dev/null +++ b/lib/gitlab/instrumentable.rb @@ -0,0 +1,58 @@ +# Used to instrument methods in the GitLab codebase +# +# Creates a lightweight wrapper around the method pointed at by DSL method call +# Under the hood this creates a Prometheus histogram, with at most 12 buckets to +# keep that instance alife. Labels are not supported yet, as the number of labels +# per histogram should remain limited, ideally to about 10. Also I didn't want +# an extra DSL method like grape as that gets messy real quick. +# +# Usage: +# class SomeClass +# include Gitlab::Instrumentable +# +# instrument_method :some_method +# +# # with custom buckets, max 12 +# instrument_method :other_method, 20..30 +# instrument_method :other_method, [1,3,5,8,12,30,60,120] +# end +require 'active_support/concern' + +module Gitlab + module Instrumentable + extend ActiveSupport::Concern + + class_methods do + def instrument_method(method, buckets = nil) + @buckets = buckets&.to_a || ::Prometheus::Client::Histogram::DEFAULT_BUCKETS + raise 'Too many buckets, limit to 12' if @buckets.size > 12 && !Rails.env.production? + + mod = Module.new do + define_method(method) do |*args| + return super(*args) if Rails.env.test? + + start_time = Time.now.to_f + res = super(*args) + record_timing_since(start_time, __method__) + + res + end + + private + + def record_timing_since(time, method) + class_name = self.class.name + @histogram ||= Gitlab::Metrics.histogram( + "#{class_name.underscore}_duration_seconds", + "Execution time for #{class_name}##{method}", + {}, @buckets) + + @histogram.observe({}, Time.now.to_f - time) + end + end + + self.prepend(mod) + end + end + end +end |