Split plugin framework into its own package

Signed-off-by: Carlisia <carlisiac@vmware.com>

pkg/plugin/framework/object_store.go

@@ -0,0 +1,44 @@
+/*
+Copyright 2019 the Velero contributors.
+
+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.
+*/
+
+package framework
+
+import (
+	"github.com/hashicorp/go-plugin"
+	"google.golang.org/grpc"
+
+	proto "github.com/heptio/velero/pkg/plugin/generated"
+)
+
+// ObjectStorePlugin is an implementation of go-plugin's Plugin
+// interface with support for gRPC for the cloudprovider/ObjectStore
+// interface.
+type ObjectStorePlugin struct {
+	plugin.NetRPCUnsupportedPlugin
+	*pluginBase
+}
+
+// GRPCClient returns an ObjectStore gRPC client.
+func (p *ObjectStorePlugin) GRPCClient(c *grpc.ClientConn) (interface{}, error) {
+	return newClientDispenser(p.clientLogger, c, newObjectStoreGRPCClient), nil
+
+}
+
+// GRPCServer registers an ObjectStore gRPC server.
+func (p *ObjectStorePlugin) GRPCServer(s *grpc.Server) error {
+	proto.RegisterObjectStoreServer(s, &ObjectStoreGRPCServer{mux: p.serverMux})
+	return nil
+}