Initial memory leak detection code.

Author: ioquatix

examples/leaks/leaks.rb

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+#!/usr/bin/env ruby
+
+require "process/metrics"
+require "async/clock"
+require "securerandom"
+
+class RingBuffer
+	def initialize(size)
+		@size = 0
+		
+		@buffer = Array.new(size)
+		@index = 0
+	end
+	
+	attr :size
+	
+	def full?
+		@size == @buffer.size
+	end
+	
+	def <<(value)
+		index = (@index + @size) % @buffer.size
+		@buffer[index] = value
+		
+		if @size < @buffer.size
+			@size += 1
+		end
+	end
+	
+	def each
+		return enum_for(:each) unless block_given?
+		
+		@size.times do |i|
+			index = (@index + i) % @buffer.size
+			yield @buffer[index]
+		end
+	end
+	
+	include Enumerable
+end
+
+class LeakDetector
+	class Sample < Struct.new(:time, :memory)
+		def self.capture
+			new(Async::Clock.now, Process::Metrics::Memory.capture(Process.pid).proportional_size)
+		end
+		
+		def delta(sample)
+			(memory - sample.memory) / (time - sample.time)
+		end
+	end
+	
+	def initialize(threshold: 0.0, interval: 10.0, samples: 12)
+		@threshold = threshold
+		@interval = interval
+		
+		@derivatives = RingBuffer.new(samples)
+		@previous_sample = nil
+	end
+	
+	def run
+		@thread = Thread.new do
+			loop do
+				capture_sample
+				check_for_leaks!
+				sleep @interval
+			end
+		end
+	end
+	
+	private
+	
+	def capture_sample
+		sample = Sample.capture
+		
+		$stderr.puts "Sample: #{sample.memory.round(2)} KB"
+		
+		if @previous_sample
+			@derivatives << sample.delta(@previous_sample)
+		end
+		
+		@previous_sample = sample
+	end
+	
+	def check_for_leaks!
+		return unless samples.full?
+		
+		average_derivative = @derivatives.sum / @derivatives.size
+		
+		if average_derivative > @threshold
+			$stderr.puts "🚨 Memory leak detected!"
+			puts "Average derivative: #{average_derivative.round(2)} KB/s"
+			puts "Cumulative derivative: #{@cumulative_derivative.round(2)} KB"
+			puts "Derivatives: #{@derivatives.map { |d| d.round(2) }.join(', ')}"
+		end
+	end
+end
+
+# Initialize and run the leak detector
+leak_detector = LeakDetector.new
+leak_detector.run
+
+leak_rate = 1024 * 1024 # 1 MB/s
+
+loop do
+	leaks = Array.new(10) do
+		SecureRandom.random_bytes(leak_rate)
+		sleep 0.1
+	end
+end