Class: FiberAudit::Runtime::Watchdog

Inherits:
Object
  • Object
show all
Defined in:
lib/fiber_audit/runtime/watchdog.rb

Overview

Monitors scheduler-owned heartbeat fibers from one dedicated process thread. rubocop:disable Metrics/ClassLength

Defined Under Namespace

Classes: Channel, Stall

Constant Summary collapse

SOURCE = 
:scheduler_watchdog
STOP_TIMEOUT_SECONDS = 
1
MAX_OVERLAP_EVENTS = 
10

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(policy:, recorder:, redactor:, active_operations:, clock: Clock.new, thread_factory: ->(&block) { Thread.new(&block) }) ⇒ Watchdog

Returns a new instance of Watchdog.



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# File 'lib/fiber_audit/runtime/watchdog.rb', line 26

def initialize(
  policy:,
  recorder:,
  redactor:,
  active_operations:,
  clock: Clock.new,
  thread_factory: ->(&block) { Thread.new(&block) }
)
  validate_dependencies!(policy, recorder, redactor, active_operations, clock, thread_factory)
  @policy = policy
  @recorder = recorder
  @redactor = redactor
  @active_operations = active_operations
  @clock = clock
  @thread_factory = thread_factory
  @mutex = Mutex.new
  @wait_mutex = Mutex.new
  @condition = ConditionVariable.new
  @channels = {}.compare_by_identity
  @stall_sequence = 0
  @unsupported_seen = false
  @monitor_thread = nil
  @stopping = false
  @stopped = false
  emit_state(policy.enabled? ? :watchdog_absent : :watchdog_disabled)
end

Instance Attribute Details

#active_operations ⇒ Object (readonly)

Returns the value of attribute active_operations.



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# File 'lib/fiber_audit/runtime/watchdog.rb', line 24

def active_operations
  @active_operations
end

#policy ⇒ Object (readonly)

Returns the value of attribute policy.



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# File 'lib/fiber_audit/runtime/watchdog.rb', line 24

def policy
  @policy
end

#recorder ⇒ Object (readonly)

Returns the value of attribute recorder.



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# File 'lib/fiber_audit/runtime/watchdog.rb', line 24

def recorder
  @recorder
end

Instance Method Details

#enabled? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/fiber_audit/runtime/watchdog.rb', line 53

def enabled?
  policy.enabled?
end

#fail_open? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/fiber_audit/runtime/watchdog.rb', line 57

def fail_open?
  recorder.session.policy.fail_open?
end

#poll(now_ns: nil) ⇒ Object 



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# File 'lib/fiber_audit/runtime/watchdog.rb', line 139

def poll(now_ns: nil)
  return state unless enabled?

  observed_now = now_ns.nil? ? @clock.monotonic_ns : Validation.integer(now_ns, 'watchdog poll time')
  @mutex.synchronize do
    @channels.each_value { |channel| poll_channel(channel, observed_now) if channel.active }
  end
  state
rescue StandardError => e
  handle_failure(e)
  raise e unless fail_open?

  :unsupported
end

#scheduler_closing(thread: Thread.current) ⇒ Object 



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# File 'lib/fiber_audit/runtime/watchdog.rb', line 115

def scheduler_closing(thread: Thread.current)
  return self unless enabled?

  now_ns = safe_monotonic_ns
  @mutex.synchronize do
    channel = @channels.delete(thread)
    next unless channel

    channel.heartbeat.request_stop
    complete_stall(channel, now_ns: now_ns, resumed: false) if channel.stall
    unless channel.active || channel.unsupported
      @unsupported_seen = true
      emit_state(:watchdog_unsupported, thread: thread)
    end
  end
  wake_monitor
  self
rescue StandardError => e
  handle_failure(e)
  raise e unless fail_open?

  self
end

#scheduler_installed(thread: Thread.current, schedule: Fiber.method(:schedule), sleeper: Kernel.method(:sleep)) ⇒ Object 



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# File 'lib/fiber_audit/runtime/watchdog.rb', line 72

def scheduler_installed(
  thread: Thread.current,
  schedule: Fiber.method(:schedule),
  sleeper: Kernel.method(:sleep)
)
  return self unless enabled?
  raise RuntimeContractError, 'scheduler thread must be a Thread' unless thread.is_a?(Thread)

  heartbeat = Heartbeat.new(
    clock: @clock,
    interval_ns: policy.heartbeat_interval_ns,
    owner_thread: thread,
    on_tick: method(:heartbeat_ticked),
    on_error: method(:heartbeat_failed)
  )
  previous = @mutex.synchronize do
    prior = @channels[thread]
    @channels[thread] = Channel.new(
      thread: thread,
      heartbeat: heartbeat,
      active: false,
      unsupported: false,
      stall: nil
    )
    prior
  end
  previous&.heartbeat&.request_stop
  heartbeat.start(schedule: schedule, sleeper: sleeper)
  self
rescue StandardError => e
  channel_failure(thread, e)
  raise e unless fail_open?

  self
end

#scheduler_unsupported(thread: Thread.current) ⇒ Object 



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# File 'lib/fiber_audit/runtime/watchdog.rb', line 108

def scheduler_unsupported(thread: Thread.current)
  return self unless enabled?

  channel_failure(thread, nil)
  self
end

#state ⇒ Object 



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# File 'lib/fiber_audit/runtime/watchdog.rb', line 61

def state
  return :disabled unless enabled?

  @mutex.synchronize do
    return :active if @channels.values.any?(&:active)
    return :unsupported if @unsupported_seen || @channels.values.any?(&:unsupported)

    :absent
  end
end

#stop ⇒ Object 



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# File 'lib/fiber_audit/runtime/watchdog.rb', line 154

def stop
  return self if @stopped

  @wait_mutex.synchronize do
    @stopping = true
    @condition.broadcast
  end
  now_ns = safe_monotonic_ns
  @mutex.synchronize do
    @channels.each_value do |channel|
      channel.heartbeat.request_stop
      complete_stall(channel, now_ns: now_ns, resumed: false) if channel.stall
      if !channel.active && !channel.unsupported
        @unsupported_seen = true
        emit_state(:watchdog_unsupported, thread: channel.thread)
      end
    end
    @channels.clear
  end
  stop_monitor_thread
  @stopped = true
  self
rescue StandardError => e
  handle_failure(e)
  @stopped = true
  raise e unless fail_open?

  self
end