bundler/bundler-api

require 'bundler_api/metriks'
require 'bundler_api/redis'

class BundlerApi::AgentReporting
  UA_REGEX = %r{^
    bundler/(?<bundler_version>#{Gem::Version::VERSION_PATTERN})\s
    rubygems/(?<gem_version>#{Gem::Version::VERSION_PATTERN})\s
    ruby/(?<ruby_version>#{Gem::Version::VERSION_PATTERN})\s
    \((?<arch>.*)\)\s
    command/(?<command>\w+)\s
    (?:options/(?<options>\S+)\s)?
    (?:ci/(?<ci>\S+)\s)?
    (?<id>.*)
  }x

  def initialize(app)
    @app = app
  end

  def call(env)
    report_user_agent(env['HTTP_USER_AGENT'])
    @app.call(env)
  end

private

  def report_user_agent(ua_string)
    return unless ua_match = UA_REGEX.match(ua_string)
    return if known_id?(ua_match['id'])

    keys = [ "versions.bundler.#{ ua_match['bundler_version'] }",
      "versions.rubygems.#{ ua_match['gem_version'] }",
      "versions.ruby.#{ ua_match['ruby_version'] }",
      "archs.#{ ua_match['arch'] }",
      "commands.#{ ua_match['command'] }",
    ]

    if ua_match['options']
      keys += ua_match['options'].split(",").map { |k| "options.#{ k }" }
    end

    if ua_match['ci']
      keys += ua_match['ci'].split(",").map { |k| "cis.#{ k }" }
    end

    keys.each do |metric|
      # Librato metric keys are limited to these characters, and 255 chars total
      metric.gsub!(/[^.:_\-0-9a-zA-Z]/, '.')
      Metriks.meter(metric[0...255]).mark
    end
  end

  def known_id?(id)
    return true if BundlerApi.redis.exists(id)

    BundlerApi.redis.setex(id, 120, true)
    false
  rescue => e
    STDERR.puts "[Error][AgentReporting] `known_id?` raised #{e.class}: #{e.message}"
    false
  end
end