Class: HunkReviewChanges::Lifecycle

Inherits:
Object
  • Object
show all
Defined in:
lib/hunk_review_changes/lifecycle.rb

Overview

Tracks the browser tab's liveness so the server can shut itself down shortly after the tab closes and never leak a process. The app records events here; the server's watchdog thread reads them.

Constant Summary collapse

BYE_GRACE =

seconds to wait after a tab says it is closing

8
SILENT_LIMIT =

a live tab that goes quiet this long is treated as crashed

900
CONNECT_LIMIT =

give up if no tab ever connects

180

Instance Method Summary collapse

Constructor Details

#initialize(clock: -> { Time.now }) ⇒ Lifecycle

Returns a new instance of Lifecycle.



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# File 'lib/hunk_review_changes/lifecycle.rb', line 12

def initialize(clock: -> { Time.now })
  @clock = clock
  @mutex = Mutex.new
  @last_heartbeat = nil
  @bye_at = nil
end

Instance Method Details

#bye! ⇒ Object 



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# File 'lib/hunk_review_changes/lifecycle.rb', line 27

def bye!
  @mutex.synchronize { @bye_at = @clock.call + BYE_GRACE }
end

#expired?(boot_time) ⇒ Boolean

Whether the server should exit now, given when it booted.

Returns:

  • (Boolean) 


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# File 'lib/hunk_review_changes/lifecycle.rb', line 32

def expired?(boot_time)
  now = @clock.call
  last, bye = @mutex.synchronize { [@last_heartbeat, @bye_at] }
  return true if bye && now >= bye
  return true if last && now - last > SILENT_LIMIT
  return true if last.nil? && now - boot_time > CONNECT_LIMIT

  false
end

#heartbeat! ⇒ Object

A fresh heartbeat (e.g. from a reload) also cancels a pending goodbye.



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# File 'lib/hunk_review_changes/lifecycle.rb', line 20

def heartbeat!
  @mutex.synchronize do
    @last_heartbeat = @clock.call
    @bye_at = nil
  end
end