Class: Wurk::ErrorCoalescer

Inherits:
Object
  • Object
show all
Defined in:
lib/wurk/error_coalescer.rb

Overview

Lets the first report of a key through, then one per window, and says how many it swallowed in between. Per process: every forked child speaks for itself, so a fleet still reports at worst children x keys per window.

Keys can come from data (an error message's first word), so at most MAX_KEYS are remembered: a new key first evicts the keys whose window has passed with nothing swallowed, then, if still full, the oldest. An evicted key's next report goes straight out.

Constant Summary collapse

DEFAULT_WINDOW = 
60
MAX_KEYS = 
1024

Instance Method Summary collapse

Constructor Details

#initialize(window: DEFAULT_WINDOW, max_keys: MAX_KEYS, clock: -> { ::Process.clock_gettime(::Process::CLOCK_MONOTONIC) }) ⇒ ErrorCoalescer

Returns a new instance of ErrorCoalescer.



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# File 'lib/wurk/error_coalescer.rb', line 16

def initialize(window: DEFAULT_WINDOW, max_keys: MAX_KEYS,
               clock: -> { ::Process.clock_gettime(::Process::CLOCK_MONOTONIC) })
  @window = window
  @max_keys = max_keys
  @clock = clock
  @lock = ::Mutex.new
  @entries = {}
end

Instance Method Details

#admit(key) ⇒ Object

The number of reports suppressed since the last one when this one should go out (0 for a first report); nil when this one should be swallowed.



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# File 'lib/wurk/error_coalescer.rb', line 27

def admit(key)
  @lock.synchronize do
    now = @clock.call
    make_room(now) unless @entries.key?(key)
    entry = (@entries[key] ||= [nil, 0])
    if entry[0] && now - entry[0] < @window
      entry[1] += 1
      next nil
    end

    suppressed = entry[1]
    entry[0] = now
    entry[1] = 0
    suppressed
  end
end

#size ⇒ Object 



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# File 'lib/wurk/error_coalescer.rb', line 44

def size = @lock.synchronize { @entries.size }