Support for python grpc - continuing the work from the pull request #4270 #4705 (#5613)

* Support for python grpc

* add few fixes

* Fixes build

* Fix python generator

* Add tests

* Fix grpc python test

* Fix tests and add incomplete python generator

* Fix python generator

* Add python generator methods

* Fix Appveyor build

* grpc python support v0.1

* Update tests

* update grpctest

* Remove duplicated code and fix a brace

* tests for flatbuffers grpc python

* Updated tests + removed SerializeToString, From String

* remove pickle import

* include missing files in ci - BUILD and generated test result

grpc/src/compiler/python_generator.h

@@ -0,0 +1,55 @@
+/*
+ *
+ * Copyright 2015, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef GRPC_INTERNAL_COMPILER_PYTHON_GENERATOR_H
+#define GRPC_INTERNAL_COMPILER_PYTHON_GENERATOR_H
+
+#include <utility>
+
+#include "src/compiler/schema_interface.h"
+
+namespace grpc_python_generator {
+
+// Data pertaining to configuration of the generator with respect to anything
+// that may be used internally at Google.
+struct GeneratorConfiguration {
+  grpc::string grpc_package_root;
+  // TODO(https://github.com/grpc/grpc/issues/8622): Drop this.
+  grpc::string beta_package_root;
+  // TODO(https://github.com/google/protobuf/issues/888): Drop this.
+  grpc::string import_prefix;
+};
+
+}  // namespace grpc_python_generator
+
+#endif  // GRPC_INTERNAL_COMPILER_PYTHON_GENERATOR_H