Add Autoconnect singleton and determine Playground connection with it.

* Refactor Playground#initialize to use #autoconnect.
* Closes #81.

lib/vanity.rb

@@ -31,6 +31,7 @@ module Vanity
 require "vanity/adapters/mock_adapter"
 # Playground.
 require "vanity/playground"
+require "vanity/autoconnect"
 require "vanity/helpers"
 # Integration with various frameworks.
 require "vanity/frameworks"

lib/vanity/autoconnect.rb

@@ -0,0 +1,61 @@
+module Vanity
+  # A singleton responsible for determining if the playground should connect
+  # to the datastore.
+  module Autoconnect
+
+     BLACKLISTED_RAILS_RAKE_TASKS = [
+      'about',
+      'assets:clean',
+      'assets:clobber',
+      'assets:environment',
+      'assets:precompile',
+      'assets:precompile:all',
+      'db:create',
+      'db:drop',
+      'db:fixtures:load',
+      'db:migrate',
+      'db:migrate:status',
+      'db:rollback',
+      'db:schema:cache:clear',
+      'db:schema:cache:dump',
+      'db:schema:dump',
+      'db:schema:load',
+      'db:seed',
+      'db:setup',
+      'db:structure:dump',
+      'db:version',
+      'doc:app',
+      'log:clear',
+      'middleware',
+      'notes',
+      'notes:custom',
+      'rails:template',
+      'rails:update',
+      'routes',
+      'secret',
+      'stats',
+      'time:zones:all',
+      'tmp:clear',
+      'tmp:create'
+    ]
+    ENVIRONMENT_VANITY_DISABLED_FLAG = "VANITY_DISABLED"
+
+    def self.playground_should_autoconnect?
+      !environment_disabled? && !in_blacklisted_rake_task?
+    end
+
+    def self.environment_disabled?
+      !!ENV[ENVIRONMENT_VANITY_DISABLED_FLAG]
+    end
+
+    def self.in_blacklisted_rake_task?
+      !(current_rake_tasks & BLACKLISTED_RAILS_RAKE_TASKS).empty?
+    end
+
+    def self.current_rake_tasks
+      ::Rake.application.top_level_tasks
+    rescue => e
+      []
+    end
+  end
+end

lib/vanity/playground.rb

@@ -21,6 +21,7 @@ class Playground
     # - namespace -- Namespace to use
     # - load_path -- Path to load experiments/metrics from
     # - logger -- Logger to use
+    # - redis -- A Redis object that will be used for the connection
     def initialize(*args)
       options = Hash === args.last ? args.pop : {}
       # In the case of Rails, use the Rails logger and collect only for
@@ -39,31 +40,22 @@ def initialize(*args)
       end
 
       @options = defaults.merge(config).merge(options)
-      if @options[:host] == 'redis' && @options.values_at(:host, :port, :db).any?
-        warn "Deprecated: please specify Redis connection as URL (\"redis://host:port/db\")"
-        establish_connection :adapter=>"redis", :host=>@options[:host], :port=>@options[:port], :database=>@options[:db] || @options[:database]
-      elsif @options[:redis]
-        @adapter = RedisAdapter.new(:redis=>@options[:redis])
-      else
-        connection_spec = args.shift || @options[:connection]
-        if connection_spec
-          connection_spec = "redis://" + connection_spec unless connection_spec[/^\w+:/]
-          establish_connection connection_spec
-        end
-      end
 
       warn "Deprecated: namespace option no longer supported directly" if @options[:namespace]
       @load_path = @options[:load_path] || DEFAULTS[:load_path]
       unless @logger = @options[:logger]
         @logger = Logger.new(STDOUT)
         @logger.level = Logger::ERROR
       end
+
+      autoconnect(@options, args) if Vanity::Autoconnect.playground_should_autoconnect?
+
       @loading = []
       @use_js = false
       self.add_participant_path = DEFAULT_ADD_PARTICIPANT_PATH
       @collecting = !!@options[:collecting]
     end
-   
+
     # Deprecated. Use redis.server instead.
     attr_accessor :host, :port, :db, :password, :namespace
 
@@ -219,7 +211,7 @@ def track!(id, count = 1)
 
 
     # -- Connection management --
- 
+
     # This is the preferred way to programmatically create a new connection (or
     # switch to a new connection). If no connection was established, the
     # playground will create a new one by calling this method with no arguments.
@@ -242,7 +234,7 @@ def track!(id, count = 1)
     #   Vanity.playground.establish_connection :adapter=>:redis,
     #                                          :host=>"redis.local"
     #
-    # @since 1.4.0 
+    # @since 1.4.0
     def establish_connection(spec = nil)
       @spec = spec
       disconnect! if @adapter
@@ -343,6 +335,23 @@ def redis
       connection
     end
 
+    protected
+
+    def autoconnect(options, arguments)
+      if options[:host] == 'redis' && options.values_at(:host, :port, :db).any?
+        warn "Deprecated: please specify Redis connection as URL (\"redis://host:port/db\")"
+        establish_connection :adapter=>"redis", :host=>options[:host], :port=>options[:port], :database=>options[:db] || options[:database]
+      elsif options[:redis]
+        @adapter = RedisAdapter.new(:redis=>options[:redis])
+      else
+        connection_spec = arguments.shift || options[:connection]
+        if connection_spec
+          connection_spec = "redis://" + connection_spec unless connection_spec[/^\w+:/]
+          establish_connection connection_spec
+        end
+      end
+    end
+
   end
 
   # In the case of Rails, use the Rails logger and collect only for

test/autoconnect_test.rb

@@ -0,0 +1,25 @@
+require "test/test_helper"
+
+context ".playground_should_autoconnect?" do
+
+  setup do
+  end
+
+  test "returns true by default" do
+    autoconnect = Vanity::Autoconnect.playground_should_autoconnect?
+    assert autoconnect == true
+  end
+
+  test "returns false if environment flag is set" do
+    ENV['VANITY_DISABLED'] = '1'
+    autoconnect = Vanity::Autoconnect.playground_should_autoconnect?
+    assert autoconnect == false
+    ENV['VANITY_DISABLED'] = nil
+  end
+
+  test "returns false if in assets:precompile rake task" do
+    Rake.expects(:application).returns(stub(:top_level_tasks => ['assets:precompile']))
+    autoconnect = Vanity::Autoconnect.playground_should_autoconnect?
+    assert autoconnect == false
+  end
+end

test/playground_test.rb

@@ -23,4 +23,15 @@ def test_reconnects_with_existing_connection
     assert_equal Vanity.playground.connection.to_s, "mock:/"
   end
 
+  def test_autoconnect_establishes_connection_by_default
+    instance = Vanity.playground
+    assert instance.connected?
+  end
+
+  def test_autoconnect_can_skip_connection
+    Vanity::Autoconnect.stubs(:playground_should_autoconnect?).returns(false)
+    instance = Vanity::Playground.new
+    assert !instance.connected?
+  end
+
 end