diff --git a/middleman-core/lib/middleman-core/configuration.rb b/middleman-core/lib/middleman-core/configuration.rb
index 58141d11..e8c9b647 100644
--- a/middleman-core/lib/middleman-core/configuration.rb
+++ b/middleman-core/lib/middleman-core/configuration.rb
@@ -70,13 +70,14 @@ module Middleman
       # @param [Symbol] key The name of the option
       # @param [Object] default The default value for the option
       # @param [String] description A human-readable description of what the option does
+      # @param [Hash] options Additional options.
       # @return [ConfigSetting]
-      def define_setting(key, default=nil, description=nil)
+      def define_setting(key, default=nil, description=nil, options={})
         raise "Setting #{key} doesn't exist" if @finalized
         raise "Setting #{key} already defined" if @settings.key?(key)
         raise 'Setting key must be a Symbol' unless key.is_a? Symbol
 
-        @settings[key] = ConfigSetting.new(key, default, description)
+        @settings[key] = ConfigSetting.new(key, default, description, options)
       end
 
       # Switch the configuration manager is finalized, it switches to read-only
@@ -94,7 +95,7 @@ module Middleman
       # Load in a list of settings
       def load_settings(other_settings)
         other_settings.each do |setting|
-          new_setting = define_setting(setting.key, setting.default, setting.description)
+          new_setting = define_setting(setting.key, setting.default, setting.description, setting.options)
           new_setting.value = setting.value if setting.value_set?
         end
       end
@@ -124,11 +125,15 @@ module Middleman
       # A human-friendly description of the setting
       attr_accessor :description
 
-      def initialize(key, default, description)
+      # Additional config.
+      attr_accessor :options
+
+      def initialize(key, default, description, options={})
         @value_set = false
         self.key = key
         self.default = default
         self.description = description
+        self.options = options
       end
 
       # The user-supplied value for this setting, overriding the default
diff --git a/middleman-core/lib/middleman-core/extension.rb b/middleman-core/lib/middleman-core/extension.rb
index cc8eeb5c..520b59c3 100644
--- a/middleman-core/lib/middleman-core/extension.rb
+++ b/middleman-core/lib/middleman-core/extension.rb
@@ -106,8 +106,8 @@ module Middleman
       # @param [Symbol] key The name of the option
       # @param [Object] default The default value for the option
       # @param [String] description A human-readable description of what the option does
-      def option(key, default=nil, description=nil)
-        config.define_setting(key, default, description)
+      def option(key, default=nil, description=nil, options={})
+        config.define_setting(key, default, description, options)
       end
 
       # Declare helpers to be added the global Middleman application.
@@ -239,6 +239,13 @@ module Middleman
       end
 
       yield @options if block_given?
+
+      @options.all_settings.each do |o|
+        next unless o.options[:required] && !o.value_set?
+
+        logger.error "The `:#{o.key}` option of the `#{self.class.ext_name}` extension is required." 
+        exit(1)
+      end
     end
 
     def bind_before_configuration
diff --git a/middleman-core/lib/middleman-core/extensions/external_pipeline.rb b/middleman-core/lib/middleman-core/extensions/external_pipeline.rb
index bcbcaf2b..2e4e3669 100644
--- a/middleman-core/lib/middleman-core/extensions/external_pipeline.rb
+++ b/middleman-core/lib/middleman-core/extensions/external_pipeline.rb
@@ -1,31 +1,19 @@
 class Middleman::Extensions::ExternalPipeline < ::Middleman::Extension
   self.supports_multiple_instances = true
 
-  option :name, nil, 'The name of the pipeline'
-  option :command, nil, 'The command to initialize'
-  option :source, nil, 'Path to merge into sitemap'
+  option :name, nil, 'The name of the pipeline', required: true
+  option :command, nil, 'The command to initialize', required: true
+  option :source, nil, 'Path to merge into sitemap', required: true
   option :latency, 0.25, 'Latency between refreshes of source'
 
   def initialize(app, config={}, &block)
     super
 
-    if options[:name].nil?
-      throw "Name is required"
-    end
-
-    if options[:command].nil?
-      throw "Command is required"
-    end
-
-    if options[:source].nil?
-      throw "Source is required"
-    end
-
     require 'thread'
 
     app.files.watch :source,
-        path: File.expand_path(options[:source], app.root),
-        latency: options[:latency]
+                    path: File.expand_path(options[:source], app.root),
+                    latency: options[:latency]
   end
 
   def after_configuration
@@ -41,7 +29,7 @@ class Middleman::Extensions::ExternalPipeline < ::Middleman::Extension
   def watch_command!
     ::IO.popen(options[:command], 'r') do |pipe|
       while buf = pipe.gets
-        without_newline = buf.sub(/\n$/,'')
+        without_newline = buf.sub(/\n$/, '')
         logger.info "== External: #{without_newline}" if without_newline.length > 0
       end
     end