nicholasjackson/minke

module Minke
  module Docker
    ##
    # ServiceDiscovery allows you to look up the publicly accessible address and port for a server
    class ServiceDiscovery
      def initialize project_name, docker_runner, docker_network = nil
        @project_name = project_name
        @docker_runner = docker_runner
        @docker_network = docker_network
      end

      ##
      # Will attempt to locate the public details for a running container given
      # its name and private port
      # Parameters:
      # - service_name: the name of the running service
      # - private_port: the private port which you wish to retrieve an address for
      # Returns:
      # public address for the container e.g. 0.0.0.0:8080
      def public_address_for service_name, private_port
        ip = ""
        ports = nil

        10.times do
          begin
            ip = @docker_runner.get_docker_ip_address
            container_details = find_container_by_name "/#{@project_name}_#{service_name}_1"
            #puts container_details
            ports = container_details.first.info['Ports'].select { |p| 
              p['PrivatePort'] == private_port.to_i
            }.first
          rescue Exception
            sleep(1)
          end
        end
        
        if ports == nil || ports['PublicPort'] == nil 
          raise "Unable to find public address for '#{service_name}' on port #{private_port}"
        end

        return "#{ip}:#{ports['PublicPort']}"
      end

      ##
      # Will attempt to locate the private details for a running container given
      # its name and private port
      # Parameters:
      # - service_name: the name of the running service
      # - private_port: the private port which you wish to retrieve an address for
      # Returns:
      # private address for the container e.g. 172.17.0.2:8080
      def bridge_address_for service_name, private_port
        ip = ""

        10.times do
          begin
            container_details = find_container_by_name "/#{@project_name}_#{service_name}_1"
            ip = container_details
              .first
              .info['NetworkSettings']['Networks']["#{@docker_network}"]['IPAddress']
            break
          rescue
            sleep(1)
          end
        end
         
        if ip.length < 1  
          raise "Unable to find bridge address for network: #{@docker_network}, container: #{service_name}, port: #{private_port}"
        end
          
        return "#{ip}:#{private_port}"
      end

      ##
      # builds an address for the given url
      def build_address url
        if url.type == 'external'
          "#{url.protocol}://#{url.address}:#{url.port}#{url.path}"
        elsif url.type == 'bridge'
          address = bridge_address_for url.address, url.port
          "#{url.protocol}://#{address}#{url.path}"
        elsif url.type == 'public'
          address = public_address_for url.address, url.port
          "#{url.protocol}://#{address}#{url.path}"
        end
      end

      private
      def find_container_by_name name
        containers = @docker_runner.running_containers
        containers.select { |c| c.info['Names'].include?(name) }
      end
    end
  end
end