NATS integration

  This change adds the following message bus behaviors:
  - Component announcement / registration
  - router registration and re-registration
  Also included is a patch addressing the incompatibility introduced by
Yajl's JSON gem ``compatibility'' layer. Ironies abound.

  Test plan:
  - Unit tests passed
  - Deploy to dev instance and ad-hock test http end points on both the
    CCNG domain and API2 domain.

Change-Id: Icc1038e990523065883b4c281920da4b2668f03d

config/cloud_controller.yml

@@ -3,6 +3,8 @@ port: 8181
 pid_filename: /tmp/cloud_controller.pid
 nats_uri: nats://127.0.0.1:4222
 
+external_domain: api2.vcap.me
+
 bootstrap_admin_email: sre@vmware.com
 
 info:

lib/cloud_controller/config.rb

@@ -76,6 +76,7 @@ def self.configure(config)
     # TODO: this introduces 2 config styles.  CC takes config
     # via per instance constructor.  Remove that in favor of this
     # method as there will be more along these lines.
+    VCAP::CloudController::MessageBus.configure(config)
     VCAP::CloudController::RestController::QuotaManager.configure(config)
     VCAP::CloudController::Models::AccountCapacity.configure(config)
   end

lib/cloud_controller/json_patch.rb

@@ -0,0 +1,12 @@
+# Copyright (c) 2012-2012 VMware, Inc.
+
+# FIXME: this is so gross
+# Monkey-patching the monkeypatch: UAA gem is unhappy because yajl/json_gem
+# ignores symbolize_names
+# The UAA client gem should probably move to Yajl...
+def JSON.parse(str, opts=JSON.default_options)
+  if opts.delete(:symbolize_names)
+    opts[:symbolize_keys] = true
+  end
+  Yajl::Parser.parse(str, opts)
+end

lib/cloud_controller/message_bus.rb

@@ -0,0 +1,52 @@
+# Copyright (c) 2012-2012 VMware, Inc.
+
+require "nats/client"
+require "vcap/component"
+require "cloud_controller/json_patch"
+
+module VCAP::CloudController::MessageBus
+  class << self
+    attr_reader :config
+    attr_reader :nats
+
+    def configure(config)
+      @config = config
+      @nats = config[:nats] || NATS
+    end
+  end
+
+  def self.register_components
+    # hook up with NATS
+    # TODO: put useful metrics in varz
+    # TODO: subscribe to the two DEA channels
+    EM.schedule do
+      nats.start(:uri => config[:nats_uri]) do
+        VCAP::Component.register(
+          :type => 'CloudController',
+          :host => VCAP.local_ip,
+          :index => config[:index],
+          :config => config,
+          # leaving the varz port / user / pwd blank to be random
+        )
+      end
+    end
+  end
+
+  def self.register_routes
+    EM.schedule do
+      # TODO: blacklist api2 in legacy CC
+      # TODO: Yajl should probably also be injected
+      router_register_message = Yajl::Encoder.encode({
+        :host => VCAP.local_ip,
+        :port => config[:port],
+        :uris => [config[:external_domain]],
+        :tags => {:component => "CloudController" },
+      })
+      nats.publish("router.register", router_register_message)
+      # Broadcast when a router restarts
+      nats.subscribe("router.start") do
+        nats.publish("router.register", router_register_message)
+      end
+    end
+  end
+end

lib/cloud_controller/runner.rb

@@ -1,4 +1,5 @@
 # Copyright (c) 2009-2012 VMware, Inc.
+require File.expand_path("../message_bus.rb", __FILE__)
 
 module VCAP::CloudController
   class Runner
@@ -83,27 +84,31 @@ def setup_db
       DB.connect(db_logger, @config[:db])
     end
 
+    def development?
+      @development ||= false
+    end
+
     def run!
       db = setup_db
       run_migrations = @run_migrations
-      development = @development
-      config = @config
-
-      port = ENV["VCAP_APP_PORT"]
-      port ||= @config[:port]
+      config = @config.dup
 
       DB.apply_migrations(db) if run_migrations
 
-      @thin_server = Thin::Server.new("0.0.0.0", port,
+      @thin_server = Thin::Server.new("0.0.0.0", config[:port],
                                       :signals => false) do
         use Rack::CommonLogger
+        VCAP::CloudController::MessageBus.register_components
+        VCAP::CloudController::MessageBus.register_routes
+
         map "/" do
-          DB.apply_migrations(db) if (run_migrations && development)
+          DB.apply_migrations(db) if (run_migrations && development?)
           run VCAP::CloudController::Controller.new(config)
         end
       end
 
       trap_signals
+
       @thin_server.threaded = true
       @thin_server.start!
     end
@@ -127,6 +132,7 @@ def merge_vcap_config
       pg_key = services.keys.select { |svc| svc =~ /postgres/i }.first
       c = services[pg_key].first["credentials"]
       @config[:db][:database] = "postgres://#{c["user"]}:#{c["password"]}@#{c["hostname"]}:#{c["port"]}/#{c["name"]}"
+      @config[:port] = ENV["VCAP_APP_PORT"]
     end
   end
 end