From 5cb2ce04871cdb46582fc66a7ccb0eb17818b7e3 Mon Sep 17 00:00:00 2001
From: FENG Zhichao <flankerfc@gmail.com>
Date: Sat, 15 Aug 2015 14:31:41 +1000
Subject: [PATCH] Add a cli option to specify backend services host if they are
 not running locally.

* e.g. Services running in Docker containers on Mac OS X need to be accessed via
Docker VM IP address instead of OS X's localhost.
---
 lib/invoker.rb                      |  1 +
 lib/invoker/cli.rb                  |  5 +++++
 lib/invoker/power/balancer.rb       |  6 +++++-
 spec/invoker/power/balancer_spec.rb | 12 ++++++++++++
 4 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/lib/invoker.rb b/lib/invoker.rb
index a45769e..553ac9f 100644
--- a/lib/invoker.rb
+++ b/lib/invoker.rb
@@ -37,6 +37,7 @@ module Invoker
   class << self
     attr_accessor :config, :tail_watchers, :commander
     attr_accessor :dns_cache, :daemonize
+    attr_accessor :backend_host
 
     alias_method :daemonize?, :daemonize
 
diff --git a/lib/invoker/cli.rb b/lib/invoker/cli.rb
index 044685a..6ba607a 100644
--- a/lib/invoker/cli.rb
+++ b/lib/invoker/cli.rb
@@ -34,10 +34,15 @@ def uninstall
       type: :boolean,
       banner: "Daemonize the server into the background",
       aliases: [:d]
+    option :backend_host,
+      type: :string,
+      banner: "Host to be used for backend services if they are not running locally. e.g. docker container services in Mac OS X",
+      aliases: [:h]
     def start(file)
       Invoker.setup_config_location
       port = options[:port] || 9000
       Invoker.daemonize = options[:daemon]
+      Invoker.backend_host = options[:backend_host]
       Invoker.load_invoker_config(file, port)
       warn_about_terminal_notifier
       warn_about_old_configuration
diff --git a/lib/invoker/power/balancer.rb b/lib/invoker/power/balancer.rb
index 58bd8fd..79ad2c9 100644
--- a/lib/invoker/power/balancer.rb
+++ b/lib/invoker/power/balancer.rb
@@ -71,7 +71,7 @@ def headers_received(headers)
 
         dns_check_response = UrlRewriter.new.select_backend_config(headers['Host'])
         if dns_check_response && dns_check_response.port
-          connection.server(session, host: '0.0.0.0', port: dns_check_response.port)
+          connection.server(session, host: backend_host, port: dns_check_response.port)
         else
           return_error_page(404)
           http_parser.reset
@@ -105,6 +105,10 @@ def frontend_disconnect(backend, name)
         connection.close_connection_after_writing if backend == session
       end
 
+      def backend_host
+        Invoker.backend_host || '0.0.0.0'
+      end
+
       private
 
       def return_error_page(status)
diff --git a/spec/invoker/power/balancer_spec.rb b/spec/invoker/power/balancer_spec.rb
index 37e9f08..3062581 100644
--- a/spec/invoker/power/balancer_spec.rb
+++ b/spec/invoker/power/balancer_spec.rb
@@ -19,4 +19,16 @@
       @balancer.headers_received(headers)
     end
   end
+
+  describe "#backend_host" do
+    it "should return localhost as default when backend host is not configured" do
+      Invoker.backend_host = nil
+      expect(@balancer.backend_host).to eql("0.0.0.0")
+    end
+
+    it "should return as per configured backend host" do
+      Invoker.backend_host = "192.168.59.103"
+      expect(@balancer.backend_host).to eql("192.168.59.103")
+    end
+  end
 end