Add basic server setup

Add a command line tool to start a simple one node server setup
of the exchange

exe/rex-server

@@ -0,0 +1,22 @@
+#!/usr/bin/env ruby
+# frozen_string_literal: true
+
+require "bundler/setup"
+require "rex"
+
+puts <<~STR
+                  __
+                / _)
+       _.----._/ /
+      /         /
+   __/ (  | (  |
+  /__.-'|_|--|_|
+  
+  Ruby Exchange (Rex)
+  Author:  Tim Kächele
+  License: AGPLv3
+STR
+
+EM.run {
+  Rex::Server::SimpleServerSetup.new(ARGV[0], ARGV[1].to_i).start
+}

lib/rex/server.rb

@@ -13,6 +13,8 @@ require_relative "server/message_processor"
 require_relative "server/websocket_server"
 
 require_relative "server/json_message_serializer"
+require_relative "server/simple_server_setup"
+
 module Rex
   module Server
     VERSION = "0.1.0"

lib/rex/server/simple_server_setup.rb

@@ -0,0 +1,54 @@
+module Rex
+  module Server
+    # Implementation of a simple one node server setup
+    #
+    # Setups/Starts
+    #
+    # - a message processor to parse and forward
+    #   messages to the matching engine
+    # - a matching engine instance to process any order book related
+    #   messages
+    # - a websocket server to accept websocket base connections and
+    #   process incoming messages
+    class SimpleServerSetup
+      def initialize(host, port)
+        matching_engine_inbox_pipe = EventMachine::Channel.new
+        matching_engine_outbox_pipe = EventMachine::Channel.new
+
+        @matching_engine = MatchingEngine.new(
+          matching_engine_inbox_pipe,
+          matching_engine_outbox_pipe
+        )
+
+        message_processor_inflow_pipe = EventMachine::Channel.new
+        message_broker = MessageBroker.new(JsonMessageSerializer.new)
+
+        @message_processor = Rex::Server::MessageProcessor.new(
+          matching_engine_inbox_pipe,
+          matching_engine_outbox_pipe,
+          message_broker,
+          message_processor_inflow_pipe
+        )
+
+        @websocket_server = Rex::Server::WebsocketServer.new(
+          message_broker,
+          message_processor_inflow_pipe,
+          host: host,
+          port: port
+        )
+      end
+
+      def start
+        @message_processor.start
+        @matching_engine.start
+        @websocket_server.start
+      end
+
+      def stop
+        @matching_engine.stop
+        @message_processor.stop
+        @websocket_server.stop
+      end
+    end
+  end
+end