Class: Hyperion::Metrics

Inherits:
Object
  • Object
show all
Defined in:
lib/hyperion/metrics.rb

Overview

Lock-free per-thread counters. Each worker thread mutates its own Hash on the hot path — no mutex acquire/release on every increment, no contention across the thread pool. ‘snapshot` aggregates lazily across all threads that have ever incremented (one short mutex section, only taken when the operator asks for stats).

Reset semantics: counters monotonically increase. Operators that want rate-of-change should snapshot, sleep, snapshot, diff.

Public API:

Hyperion.stats -> Hash with all current values across all threads.

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Metrics

Returns a new instance of Metrics.



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# File 'lib/hyperion/metrics.rb', line 16

def initialize
  @threads = Set.new
  @threads_mutex = Mutex.new
  # Each Metrics instance has its own thread-local key so spec runs that
  # build fresh Metrics objects don't share state across examples.
  @thread_key = :"__hyperion_metrics_#{object_id}__"
end

Instance Method Details

#decrement(key, by = 1) ⇒ Object 



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# File 'lib/hyperion/metrics.rb', line 30

def decrement(key, by = 1)
  increment(key, -by)
end

#increment(key, by = 1) ⇒ Object

Hot path: one TLS lookup + one hash op. No mutex.



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# File 'lib/hyperion/metrics.rb', line 25

def increment(key, by = 1)
  counters = Thread.current[@thread_key] ||= register_thread_counters
  counters[key] += by
end

#increment_status(code) ⇒ Object 



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# File 'lib/hyperion/metrics.rb', line 34

def increment_status(code)
  increment(:"responses_#{code}")
end

#reset! ⇒ Object

Tests can call .reset! between examples to avoid cross-spec leakage.



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# File 'lib/hyperion/metrics.rb', line 54

def reset!
  @threads_mutex.synchronize do
    @threads.each { |t| t[@thread_key]&.clear }
  end
end

#snapshot ⇒ Object 



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# File 'lib/hyperion/metrics.rb', line 38

def snapshot
  result = Hash.new(0)
  @threads_mutex.synchronize do
    @threads.delete_if { |t| !t.alive? }
    @threads.each do |t|
      counters = t[@thread_key]
      next unless counters

      counters.each { |k, v| result[k] += v }
    end
  end
  result.default = nil
  result
end