Expand broker functionality to include server implementation

plugins/commands/serve/broker.rb

@@ -9,6 +9,14 @@ module VagrantPlugins
     class Broker
       include Singleton
 
+      # Broker specific errors
+      class Error < StandardError
+        class StreamTimeout < Error; end
+      end
+
+      # Maximum number of seconds to wait for receiving stream connection information
+      STREAM_WAIT_TIMEOUT = 5
+
       # Protobuf connection information
       Info = ::Plugin::ConnInfo
 
@@ -36,16 +44,32 @@ module VagrantPlugins
       # is passed to our internal broker to track streams
       # for internal use.
       class Streamer < ::Plugin::GRPCBroker::Service
+        # @return [Broker]
+        attr_reader :broker
+
+        # Create a new streamer service
+        #
+        # @param broker [Broker] broker to register requests
+        # @return [self]
+        def initialize(broker:)
+          super
+          @broker = broker
+        end
+
+        # Handle stream requests which include connection
+        # information for stream IDs
         def start_stream(reqs, x)
           reqs.map do |req|
-            Broker.instance.register(req)
+            broker.register(req)
           end
           nil
         end
       end
 
-      # Create a new broker
-      def initialize
+      # Create a server side broker
+      def initialize(bind:, ports:)
+        @bind = bind
+        @ports = ports
         @streams_m = Mutex.new
         @streams = {}
       end
@@ -73,8 +97,6 @@ module VagrantPlugins
       # @note If stream information has not be received
       #       for the requested ID it will wait for the
       #       info.
-      # TODO(spox): Should we add a timeout here similar
-      #             to within go-plugin (hard coded 5s).
       def dial(id)
         catch(:found) do
           @streams_m.synchronize do
@@ -83,11 +105,57 @@ module VagrantPlugins
             if v.nil?
               v = @streams[id] = ConditionVariable.new
             end
-            v.wait(@streams_m)
+            v.wait(@streams_m, STREAM_WAIT_TIMEOUT)
+            if v == @streams[id]
+              raise Error::StreamTimeout,
+                "Failed to receive connection information for stream `#{id}'"
+            end
             @streams[id]
           end
         end
       end
+
+      def client_for(stub)
+      end
+
+      class Client
+
+        # Create a new broker
+        def initialize(client:)
+          @stream_id_m = Mutex.new
+          @stream_id = 0
+          @servers_m = Mutex.new
+          @servers = {}
+        end
+
+        # @return [Integer] next stream id to use
+        def next_id
+          @stream_id_m.synchronize do
+            @stream_id += 1
+          end
+        end
+
+      # Accept a specific stream ID and immediately
+      # serve a gRPC server on that stream ID.
+      #
+      # @param id [Integer] stream id
+      # @param services [Array<Class>] list of services to serve
+      def accept_and_serve(id, services)
+        s = GRPC::RpcServer.new
+        health_checker = Grpc::Health::Checker.new
+        port = s.add_http2_port("#{bind_addr}:0", :this_port_is_insecure)
+        services.each do |srv_klass|
+          s.handle(srv_klass.new)
+          health_checker.add_status(srv_klass,
+            Grpc::Health::V1::HealthCheckResponse::ServingStatus::SERVING)
+        end
+        s.handle(health_checker)
+        s.run_till_terminated_or_interrupted([1, 'int', 'SIGQUIT', 'SIGINT'])
+      end
+
+      ## Client side ##
+
+      end
     end
   end
 end