command_line.rb

# coding: UTF-8

module Cocaine
  class CommandLine
    class << self
      attr_accessor :logger, :runner

      def path
        @supplemental_path
      end

      def path=(supplemental_path)
        @supplemental_path = supplemental_path
        @supplemental_environment ||= {}
        @supplemental_environment['PATH'] = (Array(supplemental_path) + [ENV['PATH']]).join(File::PATH_SEPARATOR)
      end

      def environment
        @supplemental_environment ||= {}
      end

      def runner
        @runner || best_runner
      end

      def fake!
        @runner = FakeRunner.new
      end

      def unfake!
        @runner = nil
      end

      def java?
        RUBY_PLATFORM =~ /java/
      end

      private

      def best_runner
        [PosixRunner, ProcessRunner, BackticksRunner].detect do |runner|
          runner.supported?
        end.new
      end
    end

    @environment = {}

    attr_reader :exit_status, :runner

    def initialize(binary, params = "", options = {})
      @binary            = binary.dup
      @params            = params.dup
      @options           = options.dup
      @runner            = @options.delete(:runner) || self.class.runner
      @logger            = @options.delete(:logger) || self.class.logger
      @swallow_stderr    = @options.delete(:swallow_stderr)
      @expected_outcodes = @options.delete(:expected_outcodes) || [0]
      @environment       = @options.delete(:environment) || {}
    end

    def command(interpolations = {})
      cmd = []
      cmd << @binary
      cmd << interpolate(@params, interpolations)
      cmd << bit_bucket if @swallow_stderr
      cmd.join(" ").strip
    end

    def run(interpolations = {})
      output = ''
      @exit_status = nil
      begin
        full_command = command(interpolations)
        log("#{colored("Command")} :: #{full_command}")
        output = execute(full_command)
      rescue Errno::ENOENT
        raise Cocaine::CommandNotFoundError
      ensure
        @exit_status = $?.exitstatus if $?.respond_to?(:exitstatus)
      end
      if @exit_status == 127
        raise Cocaine::CommandNotFoundError
      end
      unless @expected_outcodes.include?(@exit_status)
        message = [
          "Command '#{full_command}' returned #{@exit_status}. Expected #{@expected_outcodes.join(", ")}",
          "Here is the command output:\n",
          output
        ].join("\n")
        raise Cocaine::ExitStatusError, message
      end
      output
    end

    def unix?
      RbConfig::CONFIG['host_os'] !~ /mswin|mingw/
    end

    private

    def colored(text, ansi_color = "\e[32m")
      if @logger && @logger.respond_to?(:tty?) && @logger.tty?
        "#{ansi_color}#{text}\e[0m"
      else
        text
      end
    end

    def log(text)
      if @logger
        @logger.info(text)
      end
    end

    def execute(command)
      runner.call(command, environment)
    end

    def environment
      self.class.environment.merge(@environment)
    end

    def interpolate(pattern, interpolations)
      interpolations.inject(pattern) do |command_string, (key, value)|
        command_string.gsub(/:\{?#{key}\}?/) { shell_quote(value) }
      end
    end

    def shell_quote(string)
      return "" if string.nil?
      if unix?
        if string.empty?
          "''"
        else
          string.split("'").map{|m| "'#{m}'" }.join("\\'")
        end
      else
        %{"#{string}"}
      end
    end

    def bit_bucket
      unix? ? "2>/dev/null" : "2>NUL"
    end
  end
end