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Diffstat (limited to 'lib/gitlab/metrics/base_sampler.rb')
-rw-r--r-- | lib/gitlab/metrics/base_sampler.rb | 94 |
1 files changed, 94 insertions, 0 deletions
diff --git a/lib/gitlab/metrics/base_sampler.rb b/lib/gitlab/metrics/base_sampler.rb new file mode 100644 index 00000000000..219accfc029 --- /dev/null +++ b/lib/gitlab/metrics/base_sampler.rb @@ -0,0 +1,94 @@ +require 'logger' +module Gitlab + module Metrics + class BaseSampler + def self.initialize_instance(*args) + raise "#{name} singleton instance already initialized" if @instance + @instance = new(*args) + at_exit(&@instance.method(:stop)) + @instance + end + + def self.instance + @instance + end + + attr_reader :running + + # interval - The sampling interval in seconds. + def initialize(interval) + interval_half = interval.to_f / 2 + + @interval = interval + @interval_steps = (-interval_half..interval_half).step(0.1).to_a + + @mutex = Mutex.new + end + + def enabled? + true + end + + def start + return unless enabled? + + @mutex.synchronize do + return if running + @running = true + + @thread = Thread.new do + sleep(sleep_interval) + + while running + safe_sample + + sleep(sleep_interval) + end + end + end + end + + def stop + @mutex.synchronize do + return unless running + + @running = false + + if @thread + @thread.wakeup if @thread.alive? + @thread.join + @thread = nil + end + end + end + + def safe_sample + sample + rescue => e + Rails.logger.warn("#{self.class}: #{e}, stopping") + stop + end + + def sample + raise NotImplementedError + end + + # Returns the sleep interval with a random adjustment. + # + # The random adjustment is put in place to ensure we: + # + # 1. Don't generate samples at the exact same interval every time (thus + # potentially missing anything that happens in between samples). + # 2. Don't sample data at the same interval two times in a row. + def sleep_interval + while step = @interval_steps.sample + if step != @last_step + @last_step = step + + return @interval + @last_step + end + end + end + end + end +end |