VOL-1097 : Ofagent integration for voltha 2.0

- Created a common location for python based components
- Adjusted the ofagent component to interact with voltha 2.0
- Added streaming rpc methods for rcv/send of packets to voltha api
- Adjusted voltha.proto

Change-Id: I47fb7b80878ead060b4b42bd16cb4f8aa384fdb6
diff --git a/python/ofagent/protos/third_party/__init__.py b/python/ofagent/protos/third_party/__init__.py
new file mode 100644
index 0000000..818c1b1
--- /dev/null
+++ b/python/ofagent/protos/third_party/__init__.py
@@ -0,0 +1,50 @@
+#
+# Copyright 2017 the original author or authors.
+#
+# 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.
+#
+
+"""
+This helps loading http_pb2 and annotations_pb2.
+Without this, the Python importer will not be able to process the lines:
+from google.api import http_pb2 or
+from google.api import annotations_pb2
+(Without importing these, the protobuf loader will not recognize http options
+in the protobuf definitions.)
+"""
+
+from importlib import import_module
+import os
+import sys
+
+
+class GoogleApiImporter(object):
+
+    def find_module(self, full_name, path=None):
+        if full_name == 'google.api':
+            self.path = [os.path.dirname(__file__)]
+            return self
+
+    def load_module(self, name):
+        if name in sys.modules:
+            return sys.modules[name]
+        full_name = 'ofagent.protos.third_party.' + name
+        import_module(full_name)
+        module = sys.modules[full_name]
+        sys.modules[name] = module
+        return module
+
+
+sys.meta_path.append(GoogleApiImporter())
+from google.api import http_pb2, annotations_pb2
+_ = http_pb2, annotations_pb2
diff --git a/python/ofagent/protos/third_party/google/__init__.py b/python/ofagent/protos/third_party/google/__init__.py
new file mode 100644
index 0000000..b0fb0b2
--- /dev/null
+++ b/python/ofagent/protos/third_party/google/__init__.py
@@ -0,0 +1,13 @@
+# Copyright 2017-present Open Networking Foundation
+#
+# 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.
diff --git a/python/ofagent/protos/third_party/google/api/__init__.py b/python/ofagent/protos/third_party/google/api/__init__.py
new file mode 100644
index 0000000..b0fb0b2
--- /dev/null
+++ b/python/ofagent/protos/third_party/google/api/__init__.py
@@ -0,0 +1,13 @@
+# Copyright 2017-present Open Networking Foundation
+#
+# 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.
diff --git a/python/ofagent/protos/third_party/google/api/annotations.proto b/python/ofagent/protos/third_party/google/api/annotations.proto
new file mode 100644
index 0000000..cbd18b8
--- /dev/null
+++ b/python/ofagent/protos/third_party/google/api/annotations.proto
@@ -0,0 +1,29 @@
+// Copyright (c) 2015, Google Inc.
+//
+// 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.
+
+syntax = "proto3";
+
+package google.api;
+
+import "google/api/http.proto";
+import "google/protobuf/descriptor.proto";
+
+option java_multiple_files = true;
+option java_outer_classname = "AnnotationsProto";
+option java_package = "com.google.api";
+
+extend google.protobuf.MethodOptions {
+  // See `HttpRule`.
+  HttpRule http = 72295728;
+}
diff --git a/python/ofagent/protos/third_party/google/api/http.proto b/python/ofagent/protos/third_party/google/api/http.proto
new file mode 100644
index 0000000..ce07aa1
--- /dev/null
+++ b/python/ofagent/protos/third_party/google/api/http.proto
@@ -0,0 +1,127 @@
+// Copyright (c) 2015, Google Inc.
+//
+// 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.
+
+syntax = "proto3";
+
+package google.api;
+
+option java_multiple_files = true;
+option java_outer_classname = "HttpProto";
+option java_package = "com.google.api";
+
+
+// `HttpRule` defines the mapping of an RPC method to one or more HTTP REST API
+// methods. The mapping determines what portions of the request message are
+// populated from the path, query parameters, or body of the HTTP request.  The
+// mapping is typically specified as an `google.api.http` annotation, see
+// "google/api/annotations.proto" for details.
+//
+// The mapping consists of a mandatory field specifying a path template and an
+// optional `body` field specifying what data is represented in the HTTP request
+// body. The field name for the path indicates the HTTP method. Example:
+//
+// ```
+// package google.storage.v2;
+//
+// import "google/api/annotations.proto";
+//
+// service Storage {
+//   rpc CreateObject(CreateObjectRequest) returns (Object) {
+//     option (google.api.http) {
+//       post: "/v2/{bucket_name=buckets/*}/objects"
+//       body: "object"
+//     };
+//   };
+// }
+// ```
+//
+// Here `bucket_name` and `object` bind to fields of the request message
+// `CreateObjectRequest`.
+//
+// The rules for mapping HTTP path, query parameters, and body fields
+// to the request message are as follows:
+//
+// 1. The `body` field specifies either `*` or a field path, or is
+//    omitted. If omitted, it assumes there is no HTTP body.
+// 2. Leaf fields (recursive expansion of nested messages in the
+//    request) can be classified into three types:
+//     (a) Matched in the URL template.
+//     (b) Covered by body (if body is `*`, everything except (a) fields;
+//         else everything under the body field)
+//     (c) All other fields.
+// 3. URL query parameters found in the HTTP request are mapped to (c) fields.
+// 4. Any body sent with an HTTP request can contain only (b) fields.
+//
+// The syntax of the path template is as follows:
+//
+//     Template = "/" Segments [ Verb ] ;
+//     Segments = Segment { "/" Segment } ;
+//     Segment  = "*" | "**" | LITERAL | Variable ;
+//     Variable = "{" FieldPath [ "=" Segments ] "}" ;
+//     FieldPath = IDENT { "." IDENT } ;
+//     Verb     = ":" LITERAL ;
+//
+// `*` matches a single path component, `**` zero or more path components, and
+// `LITERAL` a constant.  A `Variable` can match an entire path as specified
+// again by a template; this nested template must not contain further variables.
+// If no template is given with a variable, it matches a single path component.
+// The notation `{var}` is henceforth equivalent to `{var=*}`.
+//
+// Use CustomHttpPattern to specify any HTTP method that is not included in the
+// pattern field, such as HEAD, or "*" to leave the HTTP method unspecified for
+// a given URL path rule. The wild-card rule is useful for services that provide
+// content to Web (HTML) clients.
+message HttpRule {
+
+  // Determines the URL pattern is matched by this rules. This pattern can be
+  // used with any of the {get|put|post|delete|patch} methods. A custom method
+  // can be defined using the 'custom' field.
+  oneof pattern {
+    // Used for listing and getting information about resources.
+    string get = 2;
+
+    // Used for updating a resource.
+    string put = 3;
+
+    // Used for creating a resource.
+    string post = 4;
+
+    // Used for deleting a resource.
+    string delete = 5;
+
+    // Used for updating a resource.
+    string patch = 6;
+
+    // Custom pattern is used for defining custom verbs.
+    CustomHttpPattern custom = 8;
+  }
+
+  // The name of the request field whose value is mapped to the HTTP body, or
+  // `*` for mapping all fields not captured by the path pattern to the HTTP
+  // body.
+  string body = 7;
+
+  // Additional HTTP bindings for the selector. Nested bindings must not
+  // specify a selector and must not contain additional bindings.
+  repeated HttpRule additional_bindings = 11;
+}
+
+// A custom pattern is used for defining custom HTTP verb.
+message CustomHttpPattern {
+  // The name of this custom HTTP verb.
+  string kind = 1;
+
+  // The path matched by this custom verb.
+  string path = 2;
+}