redis_server.rb

module Test
  class RedisServer

    # Create a new redis-server instance, and start it if block given.
    #
    # @param timeout [Fixnum]
    # @param config [Hash]
    def initialize (timeout: 3, config: { }, &block)
      @owner_pid = $$
      @pid       = nil
      @timeout   = timeout
      @config    = config

      if @config[:loglevel].to_s == 'warning'
        $stderr.puts 'Test::RedisServer does not support "loglevel warning", using "notice" instead.'
        @config[:loglevel] = 'notice'
      end

      start(&block) if block
    end

    # Start redis-server instance.
    #
    # @yield [connect_info]
    # @yieldparam connect_info [Hash]
    def start
      return if @pid

      Dir.mktmpdir do |tmpdir|
        yield start_redis_server(tmpdir)
        stop
      end
    end

    private
    def start_redis_server (tmpdir)
      logfile     = "#{tmpdir}/redis-server.log"
      config_file = prepare_config_file(tmpdir)

      File.open(logfile, 'w') do |redirect|
        @pid = Process.fork do
          stderr = $stderr.dup

          begin
            exec 'redis-server', config_file, out: redirect, err: redirect
          rescue => error
            stderr.puts "exec failed: #{error}"
            exit error.errno
          end
        end
      end

      (@timeout * 10).times do
        if !Process.waitpid(@pid, Process::WNOHANG).nil?
          @pid = nil
          break
        else
          if File.read(logfile) =~ /The server is now ready to accept connections/
            return connect_info
          end
        end

        sleep 0.1
      end

      stop if @pid

      raise RuntimeError, "failed to launch redis-server\n#{File.read(logfile)}"
    end

    def prepare_config_file (directory)
      if @config[:unixsocket].nil? && @config[:port].nil?
        @config[:unixsocket] = "#{directory}/redis.sock"
        @config[:port]       = 0
      end

      if @config[:dir].nil?
        @config[:dir] = "#{directory}/"
      end

      "#{directory}/redis.conf".tap do |config_file|
        File.write(config_file, config)
      end
    end

    def config
      @config.inject('') do |memo, (key, value)|
        next if value.to_s.empty?
        memo += "#{key} #{value}\n"
      end
    end

    def connect_info
      host = @config[:bind].nil? ? '0.0.0.0' : @config[:bind]
      port = @config[:port]

      if port.is_a?(Fixnum) && port > 0
        { url: "redis://#{host}:#{port}/" }
      else
        { path: @config[:unixsocket] }
      end
    end

    def stop (signal = :TERM)
      return if @pid.nil?

      Process.kill(signal, @pid)
      while Process.waitpid(@pid, Process::WNOHANG); end
      @pid = nil
    end

  end
end