128 lines
3.4 KiB
Ruby
128 lines
3.4 KiB
Ruby
# frozen_string_literal: true
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module Gitlab
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module Memory
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# A background thread that monitors Ruby memory and calls
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# into a handler when the Ruby process violates defined limits
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# for an extended period of time.
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class Watchdog
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# This handler does nothing. It returns `false` to indicate to the
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# caller that the situation has not been dealt with so it will
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# receive calls repeatedly if fragmentation remains high.
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#
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# This is useful for "dress rehearsals" in production since it allows
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# us to observe how frequently the handler is invoked before taking action.
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class NullHandler
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include Singleton
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def call
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# NOP
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false
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end
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end
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# This handler sends SIGTERM and considers the situation handled.
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class TermProcessHandler
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def initialize(pid = $$)
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@pid = pid
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end
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def call
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Process.kill(:TERM, @pid)
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true
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end
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end
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# This handler invokes Puma's graceful termination handler, which takes
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# into account a configurable grace period during which a process may
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# remain unresponsive to a SIGTERM.
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class PumaHandler
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def initialize(puma_options = ::Puma.cli_config.options)
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@worker = ::Puma::Cluster::WorkerHandle.new(0, $$, 0, puma_options)
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end
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def call
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@worker.term
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true
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end
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end
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def initialize
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@configuration = Configuration.new
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@alive = true
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end
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##
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# Configuration for Watchdog, see Gitlab::Memory::Watchdog::Configurator
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# for examples.
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def configure
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yield configuration
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end
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def call
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event_reporter.started(log_labels)
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while @alive
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sleep(sleep_time_seconds)
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monitor
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end
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event_reporter.stopped(log_labels(memwd_reason: @reason).compact)
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end
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def stop(reason: nil)
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@reason = reason
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@alive = false
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end
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private
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attr_reader :configuration
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delegate :event_reporter, :monitors, :sleep_time_seconds, to: :configuration
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def monitor
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if monitors.empty?
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stop(reason: 'monitors are not configured')
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return
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end
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monitors.call_each do |result|
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break unless @alive
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next unless result.threshold_violated?
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event_reporter.threshold_violated(result.monitor_name)
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next unless result.strikes_exceeded?
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strike_exceeded_callback(result.monitor_name, result.payload)
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end
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end
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def strike_exceeded_callback(monitor_name, monitor_payload)
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event_reporter.strikes_exceeded(monitor_name, log_labels(monitor_payload))
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Gitlab::Memory::Reports::HeapDump.enqueue!
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stop(reason: 'successfully handled') if handler.call
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end
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def handler
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# This allows us to keep the watchdog running but turn it into "friendly mode" where
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# all that happens is we collect logs and Prometheus events for fragmentation violations.
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return NullHandler.instance unless Feature.enabled?(:enforce_memory_watchdog, type: :ops)
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configuration.handler
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end
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def log_labels(extra = {})
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extra.merge(
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memwd_handler_class: handler.class.name,
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memwd_sleep_time_s: sleep_time_seconds
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)
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end
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end
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end
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end
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