Refactor the provider config a bit to allow multiple blocks

plugins/kernel_v2/config/vm.rb

@@ -36,7 +36,7 @@ module VagrantPlugins
 
         # The providers hash defaults any key to a provider object
         @providers = Hash.new do |hash, key|
-          hash[key] = VagrantConfigProvider.new(key, nil)
+          hash[key] = VagrantConfigProvider.new(key)
         end
       end
 
@@ -94,8 +94,7 @@ module VagrantPlugins
       #
       # @param [Symbol] name The name of the provider.
       def provider(name, &block)
-        # TODO: Error if a provider is defined multiple times.
+        @providers[name].add_config_block(block) if block_given?
-        @providers[name] = VagrantConfigProvider.new(name, block)
       end
 
       def provision(name, options=nil, &block)
@@ -134,6 +133,11 @@ module VagrantPlugins
         # If we haven't defined a single VM, then we need to define a
         # default VM which just inherits the rest of the configuration.
         define(DEFAULT_VM_NAME) if defined_vm_keys.empty?
+
+        # Compile all the provider configurations
+        @providers.each do |name, config|
+          config.finalize!
+        end
       end
 
       def validate(machine)

plugins/kernel_v2/config/vm_provider.rb

@@ -7,31 +7,53 @@ module VagrantPlugins
     # Represents a single configured provider for a VM. This may or may
     # not be a valid provider. Validation is deferred until later.
     class VagrantConfigProvider
+      # This is the name of the provider, as a symbol.
+      #
+      # @return [Symbol]
       attr_reader :name
+
+      # The compiled configuration. This is only available after finalizing.
+      #
+      # @return [Object]
       attr_reader :config
 
       # Initializes a new provider configuration for a VM. This should
       # only be instantiated internally by calling `config.vm.provider`.
       #
       # @param [Symbol] name The name of the provider that is registered.
-      def initialize(name, block)
+      def initialize(name)
         @name   = name
         @config = nil
+        @config_blocks = []
         @logger = Log4r::Logger.new("vagrant::config::vm::provider")
 
         # Attempt to find the configuration class for this provider and
         # load the configuration.
-        config_class = Vagrant.plugin("2").manager.provider_configs[@name]
+        @config_class = Vagrant.plugin("2").manager.provider_configs[@name]
-        if !config_class
+        if !@config_class
           @logger.info("Provider config for #{@name} not found, ignoring config.")
-          return
+        end
       end
 
-        @logger.info("Configuring provider #{@name} with #{config_class}")
+      # This adds a configuration block to the list of configuration
-        @config = config_class.new
+      # blocks to execute when compiling the configuration.
-        block.call(@config) if block
+      def add_config_block(block)
+        @config_blocks << block
+      end
+
+      # This is called to compile the configuration
+      def finalize!
+        if @config_class
+          @logger.info("Configuring provider #{@name} with #{@config_class}")
+
+          # Call each block in order with the config object
+          @config = @config_class.new
+          @config_blocks.each { |b| b.call(@config) }
+
+          # Finalize the configuration
           @config.finalize!
         end
       end
     end
+  end
 end