benchmark.sh

#!/bin/sh

# Requires GNU time (gtime)

gtime -v ruby faraday-memory-leak.rb 2> /tmp/benchmark
cat /tmp/benchmark | grep "Maximum resident set size"

faraday-memory-leak.rb

require 'bundler/inline'

gemfile do
  source 'https://rubygems.org'

  gem 'faraday', '<1.0.0'
end

require "faraday"

connections = []

ENV["TIMES"].to_i.times do |i|
  puts i.to_s

  connection = Faraday.new("https://gstatic.com/generate_204") do |conn|
    conn.adapter Faraday.default_adapter
  end
  connections.push connection

  connection.get("/generate_204")
end

TIMES=1 ./benchmark.sh
Maximum resident set size (kbytes): 27080

TIMES=10 ./benchmark.sh
Maximum resident set size (kbytes): 35132

TIMES=100 ./benchmark.sh
Maximum resident set size (kbytes): 121972