Foreman performance analysis deep dive

000 - preformance deep dive resources.md

1. rack-mini-profiler: Swiss-army knife profiler for rails apps
2. flamegraph: Nice and useful timeline visualizer for debugging long methods.
3. memory_profiler: Easy to use memory profiler for memory consuming methods.
4. heapy: Memory dump analyzer for advanced memory analysis.
5. foreman-tracer: great tool for unintrusive tracing by lzap.

00_loggers_initializer.rb

# SQL Logger:
ActiveRecord::Base.logger = Logger.new(STDOUT)

# REST Logger:
require 'rest_client'
RestClient.log =
  Object.new.tap do |proxy|
    def proxy.<<(message)
      Rails.logger.info message
    end
  end

gemfile.local.rb

gem 'rack-mini-profiler'
# # For memory profiling (requires Ruby MRI 2.1+)
gem 'memory_profiler'
#
# For call-stack profiling flamegraphs (requires Ruby MRI 2.0.0+)
gem 'flamegraph'
gem 'stackprof'     # For Ruby MRI 2.1+
gem 'fast_stack'    # For Ruby MRI 2.0

production_installation.centos7.sh

yum install gcc
yum install rh-ruby22-ruby-devel
scl enable tfm "gem install stackprof flamegraph memory_profiler rack-mini-profiler"
# It's ugly, but it works:
cat <<EOF > /usr/share/foreman/config.ru
# This file is used by Rack-based servers to start the application.

require ::File.expand_path('../config/environment',  __FILE__)

# add requires for rack-mini-profiler and enable it:
require 'memory_profiler'
require 'stackprof'
require 'flamegraph'
require 'rack-mini-profiler'

use Rack::MiniProfiler
# /add

# apply a prefix to the application, if one is defined
# e.g. http://some.server.com/prefix where '/prefix' is defined by env variable
map ENV['RAILS_RELATIVE_URL_ROOT'] || '/'  do
  run Foreman::Application
end
EOF
systemctl restart httpd