92 lines
2.3 KiB
Ruby
92 lines
2.3 KiB
Ruby
# frozen_string_literal: true
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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 < Daemon
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attr_reader :interval
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# interval - The sampling interval in seconds.
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# warmup - When true, takes a single sample eagerly before entering the sampling loop.
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# This can be useful to ensure that all metrics files exist after `start` returns,
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# since prometheus-client-mmap creates them lazily upon first access.
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def initialize(interval: nil, logger: Logger.new($stdout), warmup: false, **options)
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interval ||= ENV[interval_env_key]&.to_i
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interval ||= self.class::DEFAULT_SAMPLING_INTERVAL_SECONDS
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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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@logger = logger
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@warmup = warmup
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super(**options)
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end
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def safe_sample
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sample
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rescue StandardError => e
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@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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private
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attr_reader :running
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def sampler_class
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self.class.name.demodulize
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end
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def interval_env_key
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"#{sampler_class.underscore.upcase}_INTERVAL_SECONDS"
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end
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def start_working
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@running = true
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safe_sample if @warmup
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true
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end
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def run_thread
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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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def stop_working
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@running = false
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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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