96 lines
2.2 KiB
Ruby
96 lines
2.2 KiB
Ruby
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require 'logger'
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module Gitlab
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module Metrics
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module Samplers
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class BaseSampler
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def self.initialize_instance(*args)
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raise "#{name} singleton instance already initialized" if @instance
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@instance = new(*args)
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at_exit(&@instance.method(:stop))
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@instance
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end
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def self.instance
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@instance
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end
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attr_reader :running
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# interval - The sampling interval in seconds.
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def initialize(interval)
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interval_half = interval.to_f / 2
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@interval = interval
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@interval_steps = (-interval_half..interval_half).step(0.1).to_a
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@mutex = Mutex.new
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end
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def enabled?
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true
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end
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def start
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return unless enabled?
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@mutex.synchronize do
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return if running
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@running = true
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@thread = Thread.new do
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sleep(sleep_interval)
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while running
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safe_sample
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sleep(sleep_interval)
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end
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end
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end
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end
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def stop
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@mutex.synchronize do
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return unless running
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@running = false
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if @thread
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@thread.wakeup if @thread.alive?
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@thread.join
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@thread = nil
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end
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end
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end
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def safe_sample
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sample
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rescue => e
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Rails.logger.warn("#{self.class}: #{e}, stopping")
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stop
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end
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def sample
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raise NotImplementedError
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end
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# Returns the sleep interval with a random adjustment.
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#
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# The random adjustment is put in place to ensure we:
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#
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# 1. Don't generate samples at the exact same interval every time (thus
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# potentially missing anything that happens in between samples).
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# 2. Don't sample data at the same interval two times in a row.
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def sleep_interval
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while step = @interval_steps.sample
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if step != @last_step
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@last_step = step
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return @interval + @last_step
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end
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end
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end
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end
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end
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end
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end
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