Send TeamCity service messages from Ruby http://confluence.jetbrains.com/display/TCD8/Build+Script+Interaction+with+TeamCity#BuildScriptInteractionwithTeamCity-ServiceMessages

teamcity.rb

class TeamCity
  def self.running?
    ENV.include? 'TEAMCITY_PROJECT_NAME'
  end

  def self.method_missing(method, *args, &block)
    return unless running?
    
    message_name = camel_case method.to_s
    publish message_name, args[0]
  end

  private
  def self.camel_case(string)
    string
      .split('_')
      .inject([]) { |buffer, e| buffer.push(buffer.empty? ? e : e.capitalize) }
      .join
  end

  def self.publish(message_name, args)
    args = [] << message_name << escaped_array_of(args)
    args = args.flatten.reject(&:nil?)

    puts "##teamcity[#{args.join(' ')}]"
  end

  def self.escape(string)
    string
      .gsub(/\|/, "||")
      .gsub(/'/, "|'")
      .gsub(/\r/, "|r")
      .gsub(/\n/, "|n")
      .gsub(/\u0085/, "|x")
      .gsub(/\u2028/, "|l")
      .gsub(/\u2029/, "|p")
      .gsub(/\[/, "|[")
      .gsub(/\]/, "|]")
  end

  def self.escaped_array_of(args)
    return [] if args.nil?

    if args.is_a? Hash
      args.map {
        |key, value| "#{key.to_s}='#{escape value.to_s}'"
      }
    else
      "'#{escape args}'"
    end
  end
end

teamcity_spec.rb

require 'tasks/teamcity'

describe "TeamCity service messages" do
  context "when running outside TeamCity" do
    before(:all) do
      @original_project = ENV['TEAMCITY_PROJECT_NAME']
      ENV.delete 'TEAMCITY_PROJECT_NAME'
    end

    after(:all) do
      ENV['TEAMCITY_PROJECT_NAME'] = @original_project
    end

    it "should not publish messages" do
      TeamCity.running?.should == false
    end
  end

  context "when running inside TeamCity" do
    before(:all) do
      @original_project = ENV['TEAMCITY_PROJECT_NAME']
      ENV['TEAMCITY_PROJECT_NAME'] = "foo"
    end

    after(:all) do
      ENV['TEAMCITY_PROJECT_NAME'] = @original_project
    end

    it "should publish messages" do
      TeamCity.running?.should == true
    end

    describe "service messages" do
      describe "escaping" do
        context "when publishing messages with special characters" do
          it "should escape apostrophes" do
            $stdout.should_receive(:puts).with("##teamcity[progressStart '|'']")
            TeamCity.progress_start "'"
          end

          it "should escape line feeds" do
            $stdout.should_receive(:puts).with("##teamcity[progressStart '|n']")
            TeamCity.progress_start "\n"
          end

          it "should escape carriage returns" do
            $stdout.should_receive(:puts).with("##teamcity[progressStart '|r']")
            TeamCity.progress_start "\r"
          end

          it "should escape next lines" do
            $stdout.should_receive(:puts).with("##teamcity[progressStart '|x']")
            TeamCity.progress_start "\u0085"
          end

          it "should escape line separators" do
            $stdout.should_receive(:puts).with("##teamcity[progressStart '|l']")
            TeamCity.progress_start "\u2028"
          end

          it "should escape paragraph separators" do
            $stdout.should_receive(:puts).with("##teamcity[progressStart '|p']")
            TeamCity.progress_start "\u2029"
          end

          it "should escape vertical bars" do
            $stdout.should_receive(:puts).with("##teamcity[progressStart '||']")
            TeamCity.progress_start '|'
          end

          it "should escape opening brackets" do
            $stdout.should_receive(:puts).with("##teamcity[progressStart '|[']")
            TeamCity.progress_start '['
          end

          it "should escape closing brackets" do
            $stdout.should_receive(:puts).with("##teamcity[progressStart '|]']")
            TeamCity.progress_start ']'
          end

          it "should escape all special characters" do
            $stdout.should_receive(:puts).with("##teamcity[progressStart '|[|r|||n|]']")
            TeamCity.progress_start "[\r|\n]"
          end
        end
      end

      describe "messages" do
        context "when reporting a message without parameters" do
          it "should print the service message" do
            $stdout.should_receive(:puts).with("##teamcity[enableServiceMessages]")
            TeamCity.enable_service_messages
          end
        end

        context "when reporting a message with an unnamed parameter" do
          it "should print the service message" do
            $stdout.should_receive(:puts).with("##teamcity[progressMessage 'the message']")
            TeamCity.progress_message "the message"
          end
        end

        context "when reporting a message with a named parameter" do
          it "should print the service message" do
            $stdout.should_receive(:puts).with("##teamcity[blockOpened name='block name']")
            TeamCity.block_opened({ :name => "block name" })
          end
        end

        context "when reporting a message with multiple named parameters" do
          it "should print the service message" do
            $stdout.should_receive(:puts).with("##teamcity[testStarted name='test name' captureStandardOutput='true']")
            TeamCity.test_started ({ :name => "test name", :captureStandardOutput => true})
          end
        end
      end
    end
  end
end