Module: NetworkResiliency::StatsEngine

Extended by:
StatsEngine
Included in:
StatsEngine
Defined in:
lib/network_resiliency/stats_engine.rb

Constant Summary collapse

LOCK = 
Thread::Mutex.new
STATS = 
{}
SYNC_LIMIT = 
100

Instance Method Summary collapse

Instance Method Details

#add(key, value) ⇒ Object 



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# File 'lib/network_resiliency/stats_engine.rb', line 9

def add(key, value)
  local, _ = synchronize do
    STATS[key] ||= [ Stats.new, Stats.new ]
  end

  local << value
end

#get(key) ⇒ Object 



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# File 'lib/network_resiliency/stats_engine.rb', line 17

def get(key)
  local, remote = synchronize do
    STATS[key] ||= [ Stats.new, Stats.new ]
  end

  local + remote
end

#reset ⇒ Object 



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# File 'lib/network_resiliency/stats_engine.rb', line 25

def reset
  synchronize { STATS.clear }
end

#sync(redis) ⇒ Object 



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# File 'lib/network_resiliency/stats_engine.rb', line 29

def sync(redis)
  dirty_keys = {}

  # select data to be synced
  data = synchronize do
    # ensure sync does not run concurrently
    return [] if @syncing
    @syncing = Thread.current

    dirty_keys = STATS.map do |key, (local, remote)|
      # skip if no new local stats and remote already synced
      next if local.n == 0 && remote.n > 0

      [ key, local.n ]
    end.compact.to_h

    # select keys to sync, prioritizing most used
    keys = dirty_keys.sort_by do |key, weight|
      -weight
    end.take(SYNC_LIMIT).map(&:first)

    # update stats for keys being synced
    keys.map do |key|
      local, remote = STATS[key]

      remote << local # update remote stats until sync completes
      STATS[key][0] = Stats.new # reset local stats

      [ key, local ]
    end.to_h
  end

  NetworkResiliency.statsd&.distribution(
    "network_resiliency.sync.keys",
    data.size,
    tags: {
      empty: data.empty?,
      truncated: data.size < dirty_keys.size,
    }.select { |_, v| v },
    sample_rate: SAMPLE_RATE[:sync],
  )

  NetworkResiliency.statsd&.distribution(
    "network_resiliency.sync.keys.dirty",
    dirty_keys.select { |_, n| n > 0 }.count,
    sample_rate: SAMPLE_RATE[:sync],
  )

  return [] if data.empty?

  # sync data to redis
  remote_stats = if NetworkResiliency.statsd
    NetworkResiliency.statsd&.time("network_resiliency.sync") do
      Stats.sync(redis, **data)
    end
  else
    Stats.sync(redis, **data)
  end

  # integrate new remote stats
  synchronize do
    remote_stats.each do |key, stats|
      local, remote = STATS[key]

      remote.reset
      remote << stats
    end
  end

  remote_stats.keys
ensure
  # release sync lock
  @syncing = nil if @syncing == Thread.current
end

#syncing? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/network_resiliency/stats_engine.rb', line 104

def syncing?
  !!@syncing
end