Add config service for handling configuration

plugins/commands/serve/service/config_service.rb

@@ -0,0 +1,86 @@
+module VagrantPlugins
+  module CommandServe
+    module Service
+      class ConfigService < ProtoService(SDK::ConfigService::Service)
+
+        CONFIG_LOCATIONS = [
+          :config,
+          :provider_configs,
+          :provisioner_configs,
+          :push_configs,
+        ]
+
+        def register(req, ctx)
+          with_plugin(ctx, CONFIG_LOCATIONS, broker: broker) do |plugin|
+            resp = SDK::Config::RegisterResponse.new
+            Vagrant.plugin("2").local_manager.registered.each do |plg|
+              plg.components.configs.each do |scope, registry|
+                registry.each do |ident, val|
+                  if plugin == val
+                    resp.scope = scope unless scope == :top
+                    resp.identifier = ident
+                    break
+                  end
+                end
+              end
+            end
+            resp
+          end
+        end
+
+        def merge_spec(*_)
+          logger.debug("generating merge spec")
+          funcspec(
+            named: {
+              base: SDK::Args::ConfigData,
+              tomerge: SDK::Args::ConfigData,
+            },
+            result: SDK::Args::ConfigData,
+          )
+        end
+
+        def merge(req, ctx)
+          with_plugin(ctx, :config, broker: broker) do |plugin|
+            base_raw = req.args.detect { |a| a.name == "base" }
+            to_merge_raw = req.args.detect { |a| a.name == "tomerge" }
+            if base_raw.nil? || to_merge_raw.nil?
+              raise ArgumentError,
+                    "Missing configuration value for merge"
+            end
+
+            base = mapper.unfuncspec(base_raw).to_ruby
+            to_merge = mapper.unfuncspec(to_merge_raw).to_ruby
+
+            result = base.merge(to_merge)
+            result.to_proto
+          end
+        end
+
+        def finalize_spec(*_)
+          funcspec(
+            args: [
+              SDK::Args::ConfigData,
+            ],
+            result: SDK::Config::FinalizeResponse
+          )
+        end
+
+        def finalize(req, ctx)
+          with_plugin(ctx, CONFIG_LOCATIONS, broker: broker) do |plugin|
+            logger.debug("finalizing configuration for plugin #{plugin}")
+            config = mapper.unfuncspec(req.args.first).to_ruby
+
+            if !config.is_a?(plugin)
+              raise TypeError,
+                    "Expected config type `#{plugin}' but received `#{config.class}'"
+            end
+            config.finalize!
+            config.instance_variable_set("@__service_finalized", true)
+
+            SDK::Config::FinalizeResponse.new(data: config.to_proto)
+          end
+        end
+      end
+    end
+  end
+end