instrumentation_tests.rb

require 'active_support'
require 'securerandom'

class SimpleInstrumentor
  class << self
    attr_accessor :events, :blocks

    def instrument(name, params = {}, &block)
      @events << name
      @blocks << name if block_given?

      yield if block_given?
    end

    def reset!
      @events = []
      @blocks = []
    end
  end
end

Shindo.tests('Excon instrumentation') do

  after do
    ActiveSupport::Notifications.unsubscribe("excon")
    ActiveSupport::Notifications.unsubscribe("excon.request")
    ActiveSupport::Notifications.unsubscribe("excon.response")
    ActiveSupport::Notifications.unsubscribe("excon.retry")
    ActiveSupport::Notifications.unsubscribe("excon.error")
    ActiveSupport::Notifications.unsubscribe("gug")
    ActiveSupport::Notifications.unsubscribe("gug.request")
    ActiveSupport::Notifications.unsubscribe("gug.response")
    ActiveSupport::Notifications.unsubscribe("gug.retry")
    ActiveSupport::Notifications.unsubscribe("gug.error")
    Delorean.back_to_the_present
    Excon.stubs.clear
  end

  before do
    SimpleInstrumentor.reset!
  end

  def subscribe(match)
    @events = []
    ActiveSupport::Notifications.subscribe(match) do |*args|
      @events << ActiveSupport::Notifications::Event.new(*args)
    end
  end

  def make_request(params = {})
    connection = Excon.new(
      'http://127.0.0.1:9292',
      :instrumentor => ActiveSupport::Notifications,
      :mock         => true
    )
    connection.get(params)
  end

  REQUEST_DELAY_SECONDS = 30
  def stub_success
    Excon.stub({:method => :get}) { |params|
      Delorean.jump REQUEST_DELAY_SECONDS
      {:body => params[:body], :headers => params[:headers], :status => 200}
    }
  end

  def stub_retries
    run_count = 0
    Excon.stub({:method => :get}) { |params|
      run_count += 1
      if run_count <= 3 # First 3 calls fail.
        raise Excon::Errors::SocketError.new(Exception.new "Mock Error")
      else
        {:body => params[:body], :headers => params[:headers], :status => 200}
      end
    }
  end

  def stub_failure
    Excon.stub({:method => :get}) { |params|
      raise Excon::Errors::SocketError.new(Exception.new "Mock Error")
    }
  end

  tests('basic notification').returns(['excon.request', 'excon.response']) do
    subscribe(/excon/)
    stub_success
    make_request
    @events.map(&:name)
  end

  tests('captures scheme, host, port, and path').returns([:host, :path, :port, :scheme]) do
    subscribe(/excon/)
    stub_success
    make_request
    [:host, :path, :port, :scheme].select {|k| @events.first.payload.has_key? k}
  end

  tests('params in request overwrite those in constructor').returns('/cheezburger') do
    subscribe(/excon/)
    stub_success
    make_request(:path => '/cheezburger')
    @events.first.payload[:path]
  end

  tests('notify on retry').returns(3) do
    subscribe(/excon/)
    stub_retries
    make_request(idempotent: true)
    @events.count{|e| e.name =~ /retry/}
  end

  tests('notify on error').returns(true) do
    subscribe(/excon/)
    stub_failure
    raises(Excon::Errors::SocketError) do
      make_request
    end

    @events.any?{|e| e.name =~ /error/}
  end

  tests('filtering').returns(['excon.request', 'excon.error']) do
    subscribe(/excon.request/)
    subscribe(/excon.error/)
    stub_failure
    raises(Excon::Errors::SocketError) do
      make_request(idempotent: true)
    end

    @events.map(&:name)
  end

  tests('more filtering').returns(['excon.retry', 'excon.retry', 'excon.retry']) do
    subscribe(/excon.retry/)
    stub_failure
    raises(Excon::Errors::SocketError) do
      make_request(idempotent: true)
    end

    @events.map(&:name)
  end

  tests('indicates duration').returns(true) do
    subscribe(/excon/)
    stub_success
    make_request
    (@events.first.duration/1000 - REQUEST_DELAY_SECONDS).abs < 1
  end

  tests('standard instrumentor') do

    tests('success').returns(
      ['excon.request', 'excon.retry', 'excon.retry', 'excon.retry', 'excon.error']) do

      begin
        original_stderr = $stderr
        $stderr = captured_stderr = StringIO.new
        stub_failure
        connection = Excon.new(
          'http://127.0.0.1:9292',
          :instrumentor => Excon::StandardInstrumentor,
          :mock         => true
        )
        raises(Excon::Errors::SocketError) do
          connection.get(:idempotent => true)
        end

        captured_stderr.string.split("\n").reject {|line| line =~ %r{^  }}.map {|event| event.split(' ').first}
      ensure
        $stderr = original_stderr
      end
    end

    tests('authorization header REDACT') do

      @auth_header = 'Basic dXNlcjpwYXNz'

      begin
        original_stderr = $stderr
        $stderr = @captured_stderr = StringIO.new
        stub_failure
        raises(Excon::Errors::SocketError) do
          @connection = Excon.new(
            'http://user:pass@127.0.0.1:9292',
            :headers      => {
              'Authorization' => @auth_header
            },
            :instrumentor => Excon::StandardInstrumentor,
            :mock         => true
          )
          @connection.get(:idempotent => true)
        end
      ensure
        $stderr = original_stderr
      end

      test('does not appear in response') do
        !@captured_stderr.string.include?(@auth_header)
      end

      test('does not mutate Authorization value') do
        @connection.data[:headers]['Authorization'] == @auth_header
      end

    end

    tests('password REDACT') do

      begin
        original_stderr = $stderr
        $stderr = @captured_stderr = StringIO.new
        stub_failure
        raises(Excon::Errors::SocketError) do
          @connection = Excon.new(
            'http://user:pass@127.0.0.1:9292',
            :instrumentor => Excon::StandardInstrumentor,
            :mock         => true
            )
          @connection.get(:idempotent => true)
        end
      ensure
        $stderr = original_stderr
      end

      @password_param = '"pass"'

      test('does not appear in response') do
        !@captured_stderr.string.include?(@password_param)
      end

      test('does not mutate password value') do
        @connection.data[:password] == "pass"
      end

    end

    tests('proxy password REDACT') do

      begin
        original_stderr = $stderr
        $stderr = @captured_stderr = StringIO.new
        stub_failure
        raises(Excon::Errors::SocketError) do
          @connection = Excon.new(
            'http://user:pass@127.0.0.1:9292',
            :instrumentor => Excon::StandardInstrumentor,
            :mock         => true,
            :proxy => { :password => "pass" }
            )
          @connection.get(:idempotent => true)
        end
      ensure
        $stderr = original_stderr
      end

      @proxy_password_param = '"pass"'

      test('does not appear in response') do
        !@captured_stderr.string.include?(@password_param)
      end

      test('does not mutate password value') do
        @connection.data[:proxy][:password] == "pass"
      end

    end

  end

  tests('use our own instrumentor').returns(
      ['excon.request', 'excon.retry', 'excon.retry', 'excon.retry', 'excon.error']) do
    stub_failure
    connection = Excon.new(
      'http://127.0.0.1:9292',
      :instrumentor => SimpleInstrumentor,
      :mock         => true
    )
    raises(Excon::Errors::SocketError) do
      connection.get(:idempotent => true)
    end

    SimpleInstrumentor.events
  end

  tests('always passes the block').returns(
      ['excon.request', 'excon.response']) do
    stub_success
    connection = Excon.new(
      'http://127.0.0.1:9292',
      :instrumentor => SimpleInstrumentor,
      :mock         => true
    )
    connection.get(:idempotent => true)

    SimpleInstrumentor.blocks
  end

  tests('does not generate events when not provided').returns(0) do
    subscribe(/excon/)
    stub_success
    connection = Excon.new('http://127.0.0.1:9292', :mock => true)
    connection.get(:idempotent => true)
    @events.count
  end

  tests('allows setting the prefix').returns(
      ['gug.request', 'gug.retry', 'gug.retry','gug.retry', 'gug.error']) do
    subscribe(/gug/)
    stub_failure
    raises(Excon::Errors::SocketError) do
      make_request(idempotent: true, instrumentor_name: 'gug')
    end
    @events.map(&:name)
  end

  tests('allows setting the prefix when not idempotent').returns(
    ['gug.request', 'gug.error']) do
    subscribe(/gug/)
    stub_failure
    raises(Excon::Errors::SocketError) do
      make_request(instrumentor_name: 'gug')
    end
    @events.map(&:name)
  end

  with_rackup('basic.ru') do
    tests('works unmocked').returns(['excon.request', 'excon.response']) do
      subscribe(/excon/)
      make_request(:mock => false)
      @events.map(&:name)
    end
  end
end