httpclient.rb

require 'manticore'

class SfdcHTTP

  attr_accessor :expiration_date, :client

  def initialize
    @client ||= set_client
    @expiration_date = nil
  end

  def self.get_client
    if @expiration_date == nil
      self.set_client
      @client
    elsif Time.now - @expiration_date < 240
      @client
    else
      self.set_client
      @client
    end
  end

  def self.set_client
    @expiration_date = Time.now
    @client = Manticore::Client.new(
      keepalive: true,
      pool_max: 50,
      pool_max_per_route: 50,
      ssl: { verify: :disable }
    )
    @client
  end

  def self.call_sfdc(n)
    if n == 4
      set_client
    end
    puts "##{n}'s request client: #{@client}"
    response = @client.get(
      'http://localhost:3000'
    ).call
    puts "##{n}s response client: #{@client}, response body: #{response.body}\n"
  end


  def self.spin_up(n_connections)
    set_client
    threads = []

    n_connections.times do |n|
      threads << Thread.new do
        call_sfdc(n)
      end
    end

    threads.each do |thread|
      thread.join
    end

  end

end

puts SfdcHTTP.spin_up(10)

response

#1's request client: #<Manticore::Client:0x15ff3e9e>
#2's request client: #<Manticore::Client:0x15ff3e9e>
#0's request client: #<Manticore::Client:0x15ff3e9e>
#5's request client: #<Manticore::Client:0x15ff3e9e>
#3's request client: #<Manticore::Client:0x15ff3e9e>
#6's request client: #<Manticore::Client:0x15ff3e9e>
#7's request client: #<Manticore::Client:0x15ff3e9e>
#8's request client: #<Manticore::Client:0x15ff3e9e>
#9's request client: #<Manticore::Client:0x15ff3e9e>
#4's request client: #<Manticore::Client:0x4d72f551>
#9s response client: #<Manticore::Client:0x4d72f551>, response body: Hello world
#5s response client: #<Manticore::Client:0x4d72f551>, response body: Hello world
#4s response client: #<Manticore::Client:0x4d72f551>, response body: Hello world
#6s response client: #<Manticore::Client:0x4d72f551>, response body: Hello world
#2s response client: #<Manticore::Client:0x4d72f551>, response body: Hello world
#1s response client: #<Manticore::Client:0x4d72f551>, response body: Hello world
#0s response client: #<Manticore::Client:0x4d72f551>, response body: Hello world
#7s response client: #<Manticore::Client:0x4d72f551>, response body: Hello world
#8s response client: #<Manticore::Client:0x4d72f551>, response body: Hello world
#3s response client: #<Manticore::Client:0x4d72f551>, response body: Hello world

server.js

var express = require('express');
var app = express();
var port = 3000;

app.get('/', function(req, res){
  setTimeout(function(){res.send('Hello world')}, 1000)
})
app.listen(port, function(){
  console.log('listening on port 3000')
})