WIP: Add support for etcd registry.

Gemfile

@@ -4,6 +4,7 @@ gem 'celluloid',        github: 'celluloid/celluloid',        branch: 'master'
 gem 'celluloid-io',     github: 'celluloid/celluloid-io',     branch: 'master'
 gem 'celluloid-zmq',    github: 'celluloid/celluloid-zmq',    branch: 'master'
 gem 'celluloid-redis',  github: 'celluloid/celluloid-redis',  branch: 'master'
+gem 'http',             github: 'tarcieri/http',              branch: 'master'
 gem 'reel',             github: 'celluloid/reel',             branch: 'master'
 
 #gem 'ffi-rzmq', github: 'chuckremes/ffi-rzmq'
@@ -15,3 +16,5 @@ gem 'coveralls',     require: false
 gemspec
 
 gem 'zk'
+gem 'etcd', '~> 0.2.0.beta.1'
+

lib/dcell/celluloid_ext.rb

@@ -13,11 +13,10 @@ class ActorProxy
     # Marshal uses respond_to? to determine if this object supports _dump so
     # unfortunately we have to monkeypatch in _dump support as the proxy
     # itself normally jacks respond_to? and proxies to the actor
-    alias_method :__respond_to?, :respond_to?
     def respond_to?(meth, check_private = false)
       return false if meth == :marshal_dump
       return true  if meth == :_dump
-      __respond_to?(meth, check_private)
+      method_missing(:respond_to?, meth, include_private)
     end
 
     # Dump an actor proxy via its mailbox

lib/dcell/registries/etcd_adapter.rb

@@ -0,0 +1,104 @@
+require 'uri'
+require 'etcd'
+
+module DCell
+  module Registry
+    class EtcdAdapter
+      PREFIX = '/dcell'
+      DEFAULT_SCHEME = 'http'
+      DEFAULT_PORT   = 4001
+
+      # Create a new connect to Etc daemon.
+      #
+      # servers: List of Etcd servers to connect to. Each server
+      # has a host/port configuration.
+      def initialize(options={})
+        options = options.inject({}) { |h,(k,v)| h[k.to_s] = v; h }
+
+        @env = options['env'] || 'production'
+        @base_path = "#{PREFIX}/#{@env}"
+
+        if options['server']
+          servers = [ options['server'] ]
+        else
+          servers = options['servers']
+        end
+
+        # Sanity check.
+        raise 'no Etcd servers given' unless servers
+
+        # Add default Etcd port unless specified.
+        servers.map! do |server|
+          if server[/:\d+$/]
+            server
+          else
+            "#{server}:#{DEFAULT_PORT}"
+          end
+        end
+
+        server = server.first
+        @etcd = Etcd.client(host: server.host, port: server.port)
+
+        server = server.is_a?(URI) ? server : URI(server)
+        if server.scheme && server.host && server.port
+          server
+        else
+          server = URI("#{DEFAULT_SCHEME}://#{server.to_s}:#{DEFAULT_PORT}")
+        end
+      end
+
+      server = servers[rand(servers.count)]
+      @etcd = Etcd.client(host: server.host,
+        port: server.port,
+        use_ssl: server.scheme == 'https' ? true : false,
+        user_name: server.user,
+        password: server.password)
+
+      @node_registry = Registry.new(@etcd, @base_path, :nodes)
+      @global_registry = Registry.new(@etcd, @base_path, :globals)
+    end
+
+    def get_node(node_id);       @node_registry.get(node_id) end
+    def set_node(node_id, addr); @node_registry.set(node_id, addr) end
+    def nodes;                   @node_registry.all end
+    def clear_nodes;             @node_registry.clear end
+
+    def get_global(key);        @global_registry.get(key) end
+    def set_global(key, value); @global_registry.set(key, value) end
+    def global_keys;            @global_registry.all end
+    def clear_globals;          @global_registry.clear end
+
+    class Registry
+      def initialize(etcd, base_path, name)
+        @etcd = etcd
+        @base_path = File.join(base_path, name.to_s)
+
+        unless @etcd.exists?(@base_path)
+          @etcd.create(@base_path, dir: true)
+        end
+      end
+
+      def get(key)
+        result = @etcd.get(File.join(base_path, key))
+        Marshal.load(result.value) 
+      end
+
+      def set(key, value)
+        path = File.join base_path, key
+        string = Marshal.dump value
+        @etcd.set(path, value: string)
+      rescue Etcd::NodeExist
+        @etcd.update(path, value: string)
+      end
+
+      def all
+        @etcd.get(@base_path).children
+      end
+
+      def clear
+        @etcd.delete(@base_path)
+        @etcd.create(@base_path, dir: true)
+      end
+    end
+  end
+end

spec/dcell/registries/etcd_adapter_spec.rb

@@ -0,0 +1,7 @@
+require 'spec_helper'
+require 'dcell/registries/etcd_adapter'
+
+describe DCell::Registry::EtcdAdapter, :pending => ENV["CI"] && "no etcd" do
+  subject { DCell::Registry::EtcdAdapter.new :server => 'localhost', :env => 'test' }
+  it_behaves_like "a DCell registry"
+end