Class: Siding::Restarter

Inherits:
Object
  • Object
show all
Defined in:
lib/siding/restarter.rb

Constant Summary collapse

MIN_INTERVAL = 
3.0
MAX_INTERVAL = 
60.0
IDLE_FRACTION = 
0.1
SETTLE = 
1.0
HANDOVER_INTERVAL = 
0.5
QUIET = 
:quiet
SETTLING = 
:settling
BOOT = 
:boot
SUPERSEDED = 
:superseded

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(manifest:, project_key:, runtime:, logger:, env: ENV, clock: nil, busy: nil, superseded: nil, on_superseded: nil, spawner: nil) ⇒ Restarter

Returns a new instance of Restarter.



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# File 'lib/siding/restarter.rb', line 21

def initialize(manifest:, project_key:, runtime:, logger:, env: ENV, clock: nil, busy: nil, superseded: nil, on_superseded: nil, spawner: nil)
  @manifest = manifest
  @project_key = project_key
  @runtime = runtime
  @logger = logger
  @env = env
  @clock = clock || -> { Process.clock_gettime(Process::CLOCK_MONOTONIC) }
  @busy = busy || -> { false }
  @superseded = superseded || -> { false }
  @on_superseded = on_superseded
  @spawner = spawner
  @gate = Mutex.new
  @signal = Thread::Queue.new
  @running = false
  @last_activity = @clock.call
end

Instance Attribute Details

#logger ⇒ Object (readonly)

Returns the value of attribute logger.



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# File 'lib/siding/restarter.rb', line 19

def logger
  @logger
end

#manifest ⇒ Object (readonly)

Returns the value of attribute manifest.



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# File 'lib/siding/restarter.rb', line 19

def manifest
  @manifest
end

#project_key ⇒ Object (readonly)

Returns the value of attribute project_key.



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# File 'lib/siding/restarter.rb', line 19

def project_key
  @project_key
end

#runtime ⇒ Object (readonly)

Returns the value of attribute runtime.



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# File 'lib/siding/restarter.rb', line 19

def runtime
  @runtime
end

Instance Method Details

#around_fork ⇒ Object 



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# File 'lib/siding/restarter.rb', line 82

def around_fork
  quiesce do
    @watch&.stop
    yield
  ensure
    @watch = start_watch if @running
  end
end

#busy! ⇒ Object Also known as: idle! 



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# File 'lib/siding/restarter.rb', line 65

def busy!
  @last_activity = @clock.call
end

#idle_seconds(now = @clock.call) ⇒ Object 



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# File 'lib/siding/restarter.rb', line 70

def idle_seconds(now = @clock.call)
  now - @last_activity
end

#interval_for(idle) ⇒ Object 



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# File 'lib/siding/restarter.rb', line 74

def interval_for(idle)
  [[idle * IDLE_FRACTION, MIN_INTERVAL].max, MAX_INTERVAL].min
end

#poll(now: @clock.call) ⇒ Object 



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# File 'lib/siding/restarter.rb', line 91

def poll(now: @clock.call)
  decision = tick(now: now)
  act(decision)
  decision
end

#quiesce ⇒ Object 



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# File 'lib/siding/restarter.rb', line 78

def quiesce
  @gate.synchronize { yield }
end

#replacement_pid ⇒ Object 



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# File 'lib/siding/restarter.rb', line 107

def replacement_pid
  pid = @replacement_pid
  return nil if pid.nil?
  return pid if alive?(pid)

  @replacement_pid = nil
end

#start ⇒ Object 



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# File 'lib/siding/restarter.rb', line 38

def start
  return self if @thread

  @watch = start_watch

  @running = true
  @thread = Thread.new { poll_loop }
  @thread.name = "siding-restarter" if @thread.respond_to?(:name=)
  self
end

#stop ⇒ Object 



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# File 'lib/siding/restarter.rb', line 49

def stop
  thread = @thread
  @running = false
  @thread = nil
  @watch&.stop
  return self if thread.nil?

  @signal << :stop
  thread.join(1) || thread.kill
  self
end

#tick(now: @clock.call) ⇒ Object 



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# File 'lib/siding/restarter.rb', line 97

def tick(now: @clock.call)
  return SUPERSEDED if @superseded.call
  return QUIET if @busy.call

  verdict = Staleness.validate(manifest, env: @env)
  return settled(QUIET) if verdict.fresh?

  settle(verdict.revision_label, now)
end

#watch_mode ⇒ Object 



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# File 'lib/siding/restarter.rb', line 61

def watch_mode
  @watch ? @watch.mode_label : "poll"
end