Add strict mode

3 files changed, 195 insertions, 22 deletions

diff --git a/lib/mixlib/config.rb b/lib/mixlib/config.rb
index 28a22b9..08b1da9 100644
--- a/lib/mixlib/config.rb
+++ b/lib/mixlib/config.rb
@@ -20,16 +20,17 @@
 
 require 'mixlib/config/version'
 require 'mixlib/config/configurable'
+require 'mixlib/config/unknown_config_option_error'
 
 module Mixlib
   module Config
     def self.extended(base)
       class << base; attr_accessor :configuration; end
       class << base; attr_accessor :configurables; end
-      class << base; attr_accessor :contexts; end
+      class << base; attr_accessor :config_contexts; end
       base.configuration = Hash.new
       base.configurables = Hash.new
-      base.contexts = Array.new
+      base.config_contexts = Array.new
     end
 
     # Loads a given ruby file, and runs instance_eval against it in the context of the current
@@ -38,7 +39,7 @@ module Mixlib
     # Raises an IOError if the file cannot be found, or is not readable.
     #
     # === Parameters
-    # <string>:: A filename to read from
+    # filename<String>:: A filename to read from
     def from_file(filename)
       self.instance_eval(IO.read(filename), filename, 1)
     end
@@ -46,7 +47,7 @@ module Mixlib
     # Pass Mixlib::Config.configure() a block, and it will yield itself
     #
     # === Parameters
-    # <block>:: A block that is called with self.configuration as the arugment.
+    # block<Block>:: A block that is called with self.configuration as the arugment.
     def configure(&block)
       block.call(self.configuration)
     end
@@ -60,9 +61,9 @@ module Mixlib
     # value:: The value of the config option
     #
     # === Raises
-    # <ArgumentError>:: If the config option does not exist
+    # <UnknownConfigOptionError>:: If the config option does not exist and strict mode is on.
     def [](config_option)
-      configurable(config_option.to_sym).get(self.configuration)
+      internal_get(config_option.to_sym)
     end
 
     # Set the value of a config option
@@ -73,6 +74,9 @@ module Mixlib
     #
     # === Returns
     # value:: The new value of the config option
+    #
+    # === Raises
+    # <UnknownConfigOptionError>:: If the config option does not exist and strict mode is on.
     def []=(config_option, value)
       internal_set(config_option, value)
     end
@@ -100,7 +104,7 @@ module Mixlib
     # Resets all config options to their defaults.
     def reset
       self.configuration = Hash.new
-      self.contexts.each { |context| context.reset }
+      self.config_contexts.each { |config_context| config_context.reset }
     end
 
     # Merge an incoming hash with our config options
@@ -132,6 +136,7 @@ module Mixlib
 
     # metaprogramming to ensure that the slot for method_symbol
     # gets set to value after any other logic is run
+    #
     # === Parameters
     # method_symbol<Symbol>:: Name of the method (variable setter)
     # blk<Block>:: logic block to run in setting slot method_symbol to value
@@ -142,6 +147,7 @@ module Mixlib
     end
 
     # metaprogramming to set the default value for the given config option
+    #
     # === Parameters
     # symbol<Symbol>:: Name of the config option
     # default_value<Object>:: Default value (can be unspecified)
@@ -190,7 +196,7 @@ module Mixlib
     #
     # For example:
     #
-    # context :server_info do
+    # config_context :server_info do
     #   configurable(:url).defaults_to("http://localhost")
     # end
     #
@@ -198,10 +204,10 @@ module Mixlib
     # symbol<Symbol>: the name of the context
     # block<Block>: a block that will be run in the context of this new config
     # class.
-    def context(symbol, &block)
+    def config_context(symbol, &block)
       context = Class.new
       context.extend(::Mixlib::Config)
-      contexts << context
+      config_contexts << context
       if block
         context.instance_eval(&block)
       end
@@ -210,6 +216,53 @@ module Mixlib
       end
     end
 
+    NOT_PASSED = Object.new
+
+    # Gets or sets strict mode.  When strict mode is on, only values which
+    # were specified with configurable(), default() or writes_with() may be
+    # retrieved or set. Getting or setting anything else will cause
+    # Mixlib::Config::UnknownConfigOptionError to be thrown.
+    #
+    # If this is set to :warn, unknown values may be get or set, but a warning
+    # will be printed with Chef::Log.warn if this occurs.
+    #
+    # === Parameters
+    # value<String>:: pass this value to set strict mode [optional]
+    #
+    # === Returns
+    # Current value of config_strict_mode
+    #
+    # === Raises
+    # <ArgumentError>:: if value is set to something other than true, false, or :warn
+    #
+    def config_strict_mode(value = NOT_PASSED)
+      if value == NOT_PASSED
+        @config_strict_mode || false
+      else
+        self.config_strict_mode = value
+      end
+    end
+
+    # Sets strict mode.  When strict mode is on, only values which
+    # were specified with configurable(), default() or writes_with() may be
+    # retrieved or set.  All other values
+    #
+    # If this is set to :warn, unknown values may be get or set, but a warning
+    # will be printed with Chef::Log.warn if this occurs.
+    #
+    # === Parameters
+    # value<String>:: pass this value to set strict mode [optional]
+    #
+    # === Raises
+    # <ArgumentError>:: if value is set to something other than true, false, or :warn
+    #
+    def config_strict_mode=(value)
+      if ![ true, false, :warn ].include?(value)
+        raise ArgumentError, "config_strict_mode must be true, false or :warn"
+      end
+      @config_strict_mode = value
+    end
+
     # Allows for simple lookups and setting of config options via method calls
     # on Mixlib::Config.  If there any arguments to the method, they are used to set
     # the value of the config option.  Otherwise, it's a simple get operation.
@@ -220,6 +273,9 @@ module Mixlib
     #
     # === Returns
     # value:: The value of the config option.
+    #
+    # === Raises
+    # <UnknownConfigOptionError>:: If the config option does not exist and strict mode is on.
     def method_missing(method_symbol, *args)
       num_args = args.length
       # Setting
@@ -229,7 +285,7 @@ module Mixlib
       end
 
       # Returning
-      configurable(method_symbol).get(self.configuration)
+      internal_get(method_symbol)
     end
 
     # Internal dispatch setter, calls the setter (def myvar=) if it is defined,
@@ -242,13 +298,38 @@ module Mixlib
     def internal_set(method_symbol,value)
       # It would be nice not to have to 
       method_name = method_symbol.id2name
+
       if self.respond_to?("#{method_name}=".to_sym)
         self.send("#{method_name}=", value)
       else
-        configurable(method_symbol).set(self.configuration, value)
+        if configurables.has_key?(method_symbol)
+          configurables[method_symbol].set(self.configuration, value)
+        else
+          if config_strict_mode == :warn
+            Chef::Log.warn("Setting unsupported config value #{method_name}..")
+          elsif self.config_strict_mode
+            raise UnknownConfigOptionError, "Cannot set unsupported config value #{method_name}."
+          end
+          configuration[method_symbol] = value
+        end
       end
     end
 
     protected :internal_set
+
+    private
+
+    def internal_get(symbol)
+      if configurables.has_key?(symbol)
+        configurables[symbol].get(self.configuration)
+      else
+        if config_strict_mode == :warn
+          Chef::Log.warn("Reading unsupported config value #{symbol}.")
+        elsif config_strict_mode
+          raise UnknownConfigOptionError, "Reading unsupported config value #{symbol}."
+        end
+        configuration[symbol]
+      end
+    end
   end
 end
diff --git a/lib/mixlib/config/unknown_config_option_error.rb b/lib/mixlib/config/unknown_config_option_error.rb
new file mode 100644
index 0000000..83dd1da
--- /dev/null
+++ b/lib/mixlib/config/unknown_config_option_error.rb
@@ -0,0 +1,24 @@
+#
+# Author:: John Keiser (<jkeiser@opscode.com>)
+# Copyright:: Copyright (c) 2013 Opscode, Inc.
+# License:: Apache License, Version 2.0
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+module Mixlib
+  module Config
+    class UnknownConfigOptionError < StandardError
+    end
+  end
+end
diff --git a/spec/mixlib/config_spec.rb b/spec/mixlib/config_spec.rb
index 4e141c8..ac45b55 100644
--- a/spec/mixlib/config_spec.rb
+++ b/spec/mixlib/config_spec.rb
@@ -32,9 +32,9 @@ describe Mixlib::Config do
   end
 
   it "should load a config file" do
-    File.stub!(:exists?).and_return(true)
-    File.stub!(:readable?).and_return(true)
-    IO.stub!(:read).with('config.rb').and_return("alpha = 'omega'\nfoo = 'bar'")
+    File.stub(:exists?).and_return(true)
+    File.stub(:readable?).and_return(true)
+    IO.stub(:read).with('config.rb').and_return("alpha = 'omega'\nfoo = 'bar'")
     lambda {
       ConfigIt.from_file('config.rb')
     }.should_not raise_error
@@ -43,7 +43,7 @@ describe Mixlib::Config do
   it "should not raise an ArgumentError with an explanation if you try and set a non-existent variable" do
     lambda {
       ConfigIt[:foobar] = "blah"
-    }.should_not raise_error(ArgumentError)
+    }.should_not raise_error
   end
 
   it "should raise an Errno::ENOENT if it can't find the file" do
@@ -53,7 +53,7 @@ describe Mixlib::Config do
   end
 
   it "should allow the error to bubble up when it's anything other than IOError" do
-    IO.stub!(:read).with('config.rb').and_return("@#asdf")
+    IO.stub(:read).with('config.rb').and_return("@#asdf")
     lambda {
       ConfigIt.from_file('config.rb')
     }.should raise_error(SyntaxError)
@@ -80,6 +80,39 @@ describe Mixlib::Config do
     ConfigIt[:arbitrary_value].should == 50
   end
 
+  describe "when strict mode is on" do
+    class StrictClass
+      extend ::Mixlib::Config
+      config_strict_mode true
+      default :x, 1
+    end
+
+    it "allows you to get and set configured values" do
+      StrictClass.x = StrictClass.x * 2
+      StrictClass[:x] = StrictClass[:x] * 2
+    end
+
+    it "raises an error when you get an arbitrary config option with .y" do
+      lambda { StrictClass.y }.should raise_error(Mixlib::Config::UnknownConfigOptionError)
+    end
+
+    it "raises an error when you get an arbitrary config option with [:y]" do
+      lambda { StrictClass[:y] }.should raise_error(Mixlib::Config::UnknownConfigOptionError)
+    end
+
+    it "raises an error when you set an arbitrary config option with .y = 10" do
+      lambda { StrictClass.y = 10 }.should raise_error(Mixlib::Config::UnknownConfigOptionError)
+    end
+
+    it "raises an error when you get an arbitrary config option with .y 10" do
+      lambda { StrictClass.y 10 }.should raise_error(Mixlib::Config::UnknownConfigOptionError)
+    end
+
+    it "raises an error when you get an arbitrary config option with [:y] = 10" do
+      lambda { StrictClass[:y] = 10 }.should raise_error(Mixlib::Config::UnknownConfigOptionError)
+    end
+  end
+
   describe "when a block has been used to set config values" do
     before do
       ConfigIt.configure { |c| c[:cookbook_path] = "monkey_rabbit"; c[:otherthing] = "boo" }
@@ -96,7 +129,7 @@ describe Mixlib::Config do
   end
 
   it "should not raise an ArgumentError if you access a config option that does not exist" do
-    lambda { ConfigIt[:snob_hobbery] }.should_not raise_error(ArgumentError)
+    lambda { ConfigIt[:snob_hobbery] }.should_not raise_error
   end
 
   it "should return true or false with has_key?" do
@@ -132,7 +165,7 @@ describe Mixlib::Config do
     end
 
     it "should multiply an integer by 1000 via from-file, too" do
-      IO.stub!(:read).with('config.rb').and_return("test_method 99")
+      IO.stub(:read).with('config.rb').and_return("test_method 99")
       @klass.from_file('config.rb')
       @klass.test_method.should == 99000
     end
@@ -317,7 +350,7 @@ describe Mixlib::Config do
       @klass = Class.new
       @klass.extend(::Mixlib::Config)
       @klass.class_eval do
-        context(:blah) do
+        config_context(:blah) do
           default :x, 5
         end
       end
@@ -351,8 +384,8 @@ describe Mixlib::Config do
       @klass = Class.new
       @klass.extend(::Mixlib::Config)
       @klass.class_eval do
-        context(:blah) do
-          context(:yarr) do
+        config_context(:blah) do
+          config_context(:yarr) do
             default :x, 5
           end
         end
@@ -381,4 +414,39 @@ describe Mixlib::Config do
       @klass.blah.yarr.x.should == 5
     end
   end
+
+  describe "When a nested context has strict mode on" do
+    class StrictClass2
+      extend ::Mixlib::Config
+      config_context :c do
+        config_strict_mode true
+        default :x, 1
+      end
+    end
+
+    it "The parent class allows you to set arbitrary config options" do
+      StrictClass2.y = 10
+    end
+
+    it "The nested class does not allow you to set arbitrary config options" do
+      lambda { StrictClass2.c.y = 10 }.should raise_error(Mixlib::Config::UnknownConfigOptionError)
+    end
+  end
+
+  describe "When strict mode is on but a nested context has strict mode unspecified" do
+    class StrictClass3
+      extend ::Mixlib::Config
+      config_strict_mode true
+      default :x, 1
+      config_context :c
+    end
+
+    it "The parent class does not allow you to set arbitrary config options" do
+      lambda { StrictClass3.y = 10 }.should raise_error(Mixlib::Config::UnknownConfigOptionError)
+    end
+
+    it "The nested class allows you to set arbitrary config options" do
+      StrictClass3.c.y = 10
+    end
+  end
 end