Working on a python example plus fixing python grpc code (#6456)

Refactored python grpc code gen

Adds example server & client + fixes ci

Fixes generated code

Making sure we encode the reply string as utf8

Adds Readme details to clarify issue regarding encoding when python is sending/receiving

15 files changed, 441 insertions, 690 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index f56f844f..ba14f7c2 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -120,7 +120,6 @@ set(FlatBuffers_Compiler_SRCS
   grpc/src/compiler/java_generator.h
   grpc/src/compiler/java_generator.cc
   grpc/src/compiler/python_generator.h
-  grpc/src/compiler/python_private_generator.h
   grpc/src/compiler/python_generator.cc
   grpc/src/compiler/swift_generator.h
   grpc/src/compiler/swift_generator.cc
diff --git a/grpc/examples/README.md b/grpc/examples/README.md
index f5694a84..c821218b 100644
--- a/grpc/examples/README.md
+++ b/grpc/examples/README.md
@@ -1,5 +1,33 @@
 ## Languages known issues
 
+### Python
+
+- Assert the type required in your server/client since python is able to receive `Bytes array` or `utf8 strings`.
+
+```python
+def SayHello(self, request, context):
+    # request might be a byte array or a utf8 string
+
+    r = HelloRequest.HelloRequest().GetRootAs(request, 0)
+    reply = "Unknown"
+    if r.Name():
+        reply = r.Name()
+    # Issues might happen if type checking isnt present.
+    # thus encoding it as a `reply.decode('UTF-8')`
+    return build_reply("welcome " + reply.decode('UTF-8'))
+
+```
+
+This can be prevented by making sure all the requests coming to/from python are `Bytes array`
+
+```python
+def say_hello(stub, builder):
+    hello_request = bytes(builder.Output())
+    reply = stub.SayHello(hello_request)
+    r = HelloReply.HelloReply.GetRootAs(reply)
+    print(r.Message())
+```
+
 ### Go
 
 - Always requires the `content-type` of the payload to be set to `application/grpc+flatbuffers`
diff --git a/grpc/examples/generate.sh b/grpc/examples/generate.sh
index 0ac2818a..b0740d8a 100644
--- a/grpc/examples/generate.sh
+++ b/grpc/examples/generate.sh
@@ -38,23 +38,34 @@ fi
 generator="--grpc $current_dir/greeter.fbs"
 
 # Regenerate Go lang code
-cd go/
+cd go
 
 cd greeter
 fbc --go ${generator}
 
 cd ${current_dir}
 
-cd swift/
+# Regenerate Python code
+cd python
+
+cd greeter
+
+fbc --python ${generator}
+
+cd ${current_dir}
+
+# Regenerate Swift code
+cd swift
 
 cd Greeter/Sources/Model
 fbc --swift ${generator}
 
 cd ${current_dir}
 
-cd ts/
+# Regenerate Typescript code
+cd ts
 
 cd greeter/src
 fbc --ts ${generator}
 
-cd ${current_dir}
\ No newline at end of file
+cd ${current_dir}
diff --git a/grpc/examples/python/greeter/README.md b/grpc/examples/python/greeter/README.md
new file mode 100644
index 00000000..fcf310c0
--- /dev/null
+++ b/grpc/examples/python/greeter/README.md
@@ -0,0 +1,12 @@
+# Python Greeter example
+
+## Prerequisite
+
+- You need to have grpc python installed on your device `pip install grpcio`
+## How to run Server:
+
+- `python server.py ${PORT}`
+
+## How to run Client:
+
+- `python client.py ${PORT} ${NAME}`
\ No newline at end of file
diff --git a/grpc/examples/python/greeter/client.py b/grpc/examples/python/greeter/client.py
new file mode 100644
index 00000000..d2d71845
--- /dev/null
+++ b/grpc/examples/python/greeter/client.py
@@ -0,0 +1,40 @@
+import sys		
+import argparse
+import grpc
+
+sys.path.insert(0, '../../../../../flatbuffers/python')
+
+import flatbuffers
+from models import HelloReply, HelloRequest, greeter_grpc_fb
+
+parser = argparse.ArgumentParser()
+parser.add_argument("port", help="server port to connect to", default=3000)
+parser.add_argument("name", help="name to be sent to server", default="flatbuffers")
+
+def say_hello(stub, hello_request):
+    reply = stub.SayHello(hello_request)
+    r = HelloReply.HelloReply.GetRootAs(reply)
+    print(r.Message())
+
+def say_many_hellos(stub, hello_request):
+    greetings = stub.SayManyHellos(hello_request)
+    for greeting in greetings:
+        r = HelloReply.HelloReply.GetRootAs(greeting)
+        print(r.Message())
+
+def main():
+    args = parser.parse_args()
+
+    with grpc.insecure_channel('localhost:' + args.port) as channel:
+        builder = flatbuffers.Builder()		
+        ind = builder.CreateString(args.name)
+        HelloRequest.HelloRequestStart(builder)
+        HelloRequest.HelloRequestAddName(builder, ind)
+        root = HelloRequest.HelloRequestEnd(builder)
+        builder.Finish(root)
+        output = bytes(builder.Output())
+        stub = greeter_grpc_fb.GreeterStub(channel)
+        say_hello(stub, output)
+        say_many_hellos(stub, output)
+
+main()
\ No newline at end of file
diff --git a/grpc/examples/python/greeter/models/HelloReply.py b/grpc/examples/python/greeter/models/HelloReply.py
new file mode 100644
index 00000000..95434dcc
--- /dev/null
+++ b/grpc/examples/python/greeter/models/HelloReply.py
@@ -0,0 +1,45 @@
+# automatically generated by the FlatBuffers compiler, do not modify
+
+# namespace: models
+
+import flatbuffers
+from flatbuffers.compat import import_numpy
+np = import_numpy()
+
+class HelloReply(object):
+    __slots__ = ['_tab']
+
+    @classmethod
+    def GetRootAs(cls, buf, offset=0):
+        n = flatbuffers.encode.Get(flatbuffers.packer.uoffset, buf, offset)
+        x = HelloReply()
+        x.Init(buf, n + offset)
+        return x
+
+    @classmethod
+    def GetRootAsHelloReply(cls, buf, offset=0):
+        """This method is deprecated. Please switch to GetRootAs."""
+        return cls.GetRootAs(buf, offset)
+    # HelloReply
+    def Init(self, buf, pos):
+        self._tab = flatbuffers.table.Table(buf, pos)
+
+    # HelloReply
+    def Message(self):
+        o = flatbuffers.number_types.UOffsetTFlags.py_type(self._tab.Offset(4))
+        if o != 0:
+            return self._tab.String(o + self._tab.Pos)
+        return None
+
+def Start(builder): builder.StartObject(1)
+def HelloReplyStart(builder):
+    """This method is deprecated. Please switch to Start."""
+    return Start(builder)
+def AddMessage(builder, message): builder.PrependUOffsetTRelativeSlot(0, flatbuffers.number_types.UOffsetTFlags.py_type(message), 0)
+def HelloReplyAddMessage(builder, message):
+    """This method is deprecated. Please switch to AddMessage."""
+    return AddMessage(builder, message)
+def End(builder): return builder.EndObject()
+def HelloReplyEnd(builder):
+    """This method is deprecated. Please switch to End."""
+    return End(builder)
\ No newline at end of file
diff --git a/grpc/examples/python/greeter/models/HelloRequest.py b/grpc/examples/python/greeter/models/HelloRequest.py
new file mode 100644
index 00000000..0263095e
--- /dev/null
+++ b/grpc/examples/python/greeter/models/HelloRequest.py
@@ -0,0 +1,45 @@
+# automatically generated by the FlatBuffers compiler, do not modify
+
+# namespace: models
+
+import flatbuffers
+from flatbuffers.compat import import_numpy
+np = import_numpy()
+
+class HelloRequest(object):
+    __slots__ = ['_tab']
+
+    @classmethod
+    def GetRootAs(cls, buf, offset=0):
+        n = flatbuffers.encode.Get(flatbuffers.packer.uoffset, buf, offset)
+        x = HelloRequest()
+        x.Init(buf, n + offset)
+        return x
+
+    @classmethod
+    def GetRootAsHelloRequest(cls, buf, offset=0):
+        """This method is deprecated. Please switch to GetRootAs."""
+        return cls.GetRootAs(buf, offset)
+    # HelloRequest
+    def Init(self, buf, pos):
+        self._tab = flatbuffers.table.Table(buf, pos)
+
+    # HelloRequest
+    def Name(self):
+        o = flatbuffers.number_types.UOffsetTFlags.py_type(self._tab.Offset(4))
+        if o != 0:
+            return self._tab.String(o + self._tab.Pos)
+        return None
+
+def Start(builder): builder.StartObject(1)
+def HelloRequestStart(builder):
+    """This method is deprecated. Please switch to Start."""
+    return Start(builder)
+def AddName(builder, name): builder.PrependUOffsetTRelativeSlot(0, flatbuffers.number_types.UOffsetTFlags.py_type(name), 0)
+def HelloRequestAddName(builder, name):
+    """This method is deprecated. Please switch to AddName."""
+    return AddName(builder, name)
+def End(builder): return builder.EndObject()
+def HelloRequestEnd(builder):
+    """This method is deprecated. Please switch to End."""
+    return End(builder)
\ No newline at end of file
diff --git a/grpc/examples/python/greeter/models/__init__.py b/grpc/examples/python/greeter/models/__init__.py
new file mode 100644
index 00000000..e69de29b
--- /dev/null
+++ b/grpc/examples/python/greeter/models/__init__.py
diff --git a/grpc/examples/python/greeter/models/greeter_grpc_fb.py b/grpc/examples/python/greeter/models/greeter_grpc_fb.py
new file mode 100644
index 00000000..b9f8a4ed
--- /dev/null
+++ b/grpc/examples/python/greeter/models/greeter_grpc_fb.py
@@ -0,0 +1,52 @@
+# Generated by the gRPC Python protocol compiler plugin. DO NOT EDIT!
+
+import grpc
+
+class GreeterStub(object):
+  """ Interface exported by the server. """  
+  
+  def __init__(self, channel):
+    """ Constructor. 
+    
+    Args: 
+    channel: A grpc.Channel. 
+    """
+    
+    self.SayHello = channel.unary_unary(
+      "/models.Greeter/SayHello"
+      )
+    
+    self.SayManyHellos = channel.unary_stream(
+      "/models.Greeter/SayManyHellos"
+      )
+    
+
+class GreeterServicer(object):
+  """ Interface exported by the server. """  
+  
+  def SayHello(self, request, context):
+    context.set_code(grpc.StatusCode.UNIMPLEMENTED)
+    context.set_details('Method not implemented!')
+    raise NotImplementedError('Method not implemented!')
+  
+  
+  def SayManyHellos(self, request, context):
+    context.set_code(grpc.StatusCode.UNIMPLEMENTED)
+    context.set_details('Method not implemented!')
+    raise NotImplementedError('Method not implemented!')
+  
+  
+
+def add_GreeterServicer_to_server(servicer, server):
+  rpc_method_handlers = {
+    'SayHello': grpc.unary_unary_rpc_method_handler(
+      servicer.SayHello
+    ),
+    'SayManyHellos': grpc.unary_stream_rpc_method_handler(
+      servicer.SayManyHellos
+    ),
+  }
+  generic_handler = grpc.method_handlers_generic_handler(
+    'models.Greeter', rpc_method_handlers)
+  server.add_generic_rpc_handlers((generic_handler,))
+
diff --git a/grpc/examples/python/greeter/server.py b/grpc/examples/python/greeter/server.py
new file mode 100644
index 00000000..acca880b
--- /dev/null
+++ b/grpc/examples/python/greeter/server.py
@@ -0,0 +1,57 @@
+from concurrent import futures
+import sys		
+import argparse
+import grpc
+
+sys.path.insert(0, '../../../../../flatbuffers/python')
+
+import flatbuffers
+from models import HelloReply, HelloRequest, greeter_grpc_fb
+
+parser = argparse.ArgumentParser()
+parser.add_argument("port", help="server on port", default=3000)
+
+def build_reply(message):
+    builder = flatbuffers.Builder()		
+    ind = builder.CreateString(message)
+    HelloReply.HelloReplyStart(builder)
+    HelloReply.HelloReplyAddMessage(builder, ind)
+    root = HelloReply.HelloReplyEnd(builder)
+    builder.Finish(root)
+    return bytes(builder.Output())
+
+class GreeterServicer(greeter_grpc_fb.GreeterServicer):
+
+    def __init__(self):
+        self.greetings = ["Hi", "Hallo", "Ciao"]
+
+    def SayHello(self, request, context):
+        r = HelloRequest.HelloRequest().GetRootAs(request, 0)
+        reply = "Unknown"
+        if r.Name():
+            reply = r.Name()
+        return build_reply("welcome " + reply.decode('UTF-8'))
+
+    def SayManyHellos(self, request, context):
+        r = HelloRequest.HelloRequest().GetRootAs(request, 0)
+        reply = "Unknown"
+        if r.Name():
+            reply = r.Name()
+
+        for greeting in self.greetings:
+            print(type(reply))
+            yield build_reply(greeting + " " + reply.decode('UTF-8'))
+        
+
+def serve():
+    args = parser.parse_args()
+    server = grpc.server(futures.ThreadPoolExecutor(max_workers=10))
+    greeter_grpc_fb.add_GreeterServicer_to_server(
+        GreeterServicer(), server
+    )
+    server.add_insecure_port('[::]:' + args.port)
+    server.start()
+    server.wait_for_termination()
+
+if __name__ == '__main__':
+    serve()
\ No newline at end of file
diff --git a/grpc/src/compiler/BUILD b/grpc/src/compiler/BUILD
index 23fe5405..88e27e80 100644
--- a/grpc/src/compiler/BUILD
+++ b/grpc/src/compiler/BUILD
@@ -79,7 +79,6 @@ cc_library(
     ],
     hdrs = [
         "python_generator.h",
-        "python_private_generator.h",
         ":common_headers",
     ],
     include_prefix = "src/compiler",
diff --git a/grpc/src/compiler/python_generator.cc b/grpc/src/compiler/python_generator.cc
index 3fcf7ea4..8108db45 100644
--- a/grpc/src/compiler/python_generator.cc
+++ b/grpc/src/compiler/python_generator.cc
@@ -16,608 +16,133 @@
  *
  */
 
-#include <algorithm>
-#include <cassert>
-#include <cctype>
-#include <cstring>
-#include <fstream>
-#include <iostream>
 #include <map>
-#include <memory>
-#include <ostream>
-#include <set>
 #include <sstream>
-#include <tuple>
-#include <vector>
 
 #include "flatbuffers/util.h"
 #include "src/compiler/python_generator.h"
-#include "src/compiler/python_private_generator.h"
-
-using std::make_pair;
-using std::map;
-using std::pair;
-using std::replace;
-using std::tuple;
-using std::vector;
-using std::set;
 
 namespace grpc_python_generator {
 
-grpc::string generator_file_name;
-
-typedef map<grpc::string, grpc::string> StringMap;
-typedef vector<grpc::string> StringVector;
-typedef tuple<grpc::string, grpc::string> StringPair;
-typedef set<StringPair> StringPairSet;
-
-// Provides RAII indentation handling. Use as:
-// {
-//   IndentScope raii_my_indent_var_name_here(my_py_printer);
-//   // constructor indented my_py_printer
-//   ...
-//   // destructor called at end of scope, un-indenting my_py_printer
-// }
-class IndentScope {
- public:
-  explicit IndentScope(grpc_generator::Printer* printer) : printer_(printer) {
-    printer_->Indent();
-  }
-
-  ~IndentScope() { printer_->Outdent(); }
-
- private:
-  grpc_generator::Printer* printer_;
-};
+grpc::string GenerateMethodType(const grpc_generator::Method *method) {
 
-inline grpc::string StringReplace(grpc::string str, const grpc::string& from,
-                                  const grpc::string& to, bool replace_all) {
-  size_t pos = 0;
+  if (method->NoStreaming())
+    return "unary_unary";
 
-  do {
-    pos = str.find(from, pos);
-    if (pos == grpc::string::npos) {
-      break;
-    }
-    str.replace(pos, from.length(), to);
-    pos += to.length();
-  } while (replace_all);
+  if (method->ServerStreaming())
+    return "unary_stream";
 
-  return str;
-}
-
-inline grpc::string StringReplace(grpc::string str, const grpc::string& from,
-                                  const grpc::string& to) {
-  return StringReplace(str, from, to, true);
-}
+  if (method->ClientStreaming())
+    return "stream_unary";
 
-grpc::string ModuleName(const grpc::string& filename,
-                        const grpc::string& import_prefix) {
-  grpc::string basename = flatbuffers::StripExtension(filename);
-  basename = StringReplace(basename, "-", "_");
-  basename = StringReplace(basename, "/", ".");
-  return import_prefix + basename + "_fb";
+  return "stream_stream";
 }
 
-grpc::string ModuleAlias(const grpc::string& filename,
-                         const grpc::string& import_prefix) {
-  grpc::string module_name = ModuleName(filename, import_prefix);
-  // We can't have dots in the module name, so we replace each with _dot_.
-  // But that could lead to a collision between a.b and a_dot_b, so we also
-  // duplicate each underscore.
-  module_name = StringReplace(module_name, "_", "__");
-  module_name = StringReplace(module_name, ".", "_dot_");
-  return module_name;
-}
-
-PrivateGenerator::PrivateGenerator(const GeneratorConfiguration& config_,
-                                   const grpc_generator::File* file_)
-    : config(config_), file(file_) {}
-
-void PrivateGenerator::PrintBetaServicer(const grpc_generator::Service* service,
-                                         grpc_generator::Printer* out) {
-  StringMap service_dict;
-  service_dict["Service"] = service->name();
-  out->Print("\n\n");
-  out->Print(service_dict, "class Beta$Service$Servicer(object):\n");
-  {
-    IndentScope raii_class_indent(out);
-    out->Print(
-        "\"\"\"The Beta API is deprecated for 0.15.0 and later.\n"
-        "\nIt is recommended to use the GA API (classes and functions in this\n"
-        "file not marked beta) for all further purposes. This class was "
-        "generated\n"
-        "only to ease transition from grpcio<0.15.0 to "
-        "grpcio>=0.15.0.\"\"\"\n");
-    for (int i = 0; i < service->method_count(); ++i) {
-      auto method = service->method(i);
-      grpc::string arg_name =
-          method->ClientStreaming() ? "request_iterator" : "request";
-      StringMap method_dict;
-      method_dict["Method"] = method->name();
-      method_dict["ArgName"] = arg_name;
-      out->Print(method_dict, "def $Method$(self, $ArgName$, context):\n");
-      {
-        IndentScope raii_method_indent(out);
-        out->Print("context.code(beta_interfaces.StatusCode.UNIMPLEMENTED)\n");
-      }
-    }
-  }
-}
+grpc::string GenerateMethodInput(const grpc_generator::Method *method) {
 
-void PrivateGenerator::PrintBetaStub(const grpc_generator::Service* service,
-                                     grpc_generator::Printer* out) {
-  StringMap service_dict;
-  service_dict["Service"] = service->name();
-  out->Print("\n\n");
-  out->Print(service_dict, "class Beta$Service$Stub(object):\n");
-  {
-    IndentScope raii_class_indent(out);
-    out->Print(
-        "\"\"\"The Beta API is deprecated for 0.15.0 and later.\n"
-        "\nIt is recommended to use the GA API (classes and functions in this\n"
-        "file not marked beta) for all further purposes. This class was "
-        "generated\n"
-        "only to ease transition from grpcio<0.15.0 to "
-        "grpcio>=0.15.0.\"\"\"\n");
-    for (int i = 0; i < service->method_count(); ++i) {
-      auto method = service->method(i);
-      grpc::string arg_name =
-          method->ClientStreaming() ? "request_iterator" : "request";
-      StringMap method_dict;
-      method_dict["Method"] = method->name();
-      method_dict["ArgName"] = arg_name;
-      out->Print(method_dict,
-                 "def $Method$(self, $ArgName$, timeout, metadata=None, "
-                 "with_call=False, protocol_options=None):\n");
-      {
-        IndentScope raii_method_indent(out);
-        out->Print("raise NotImplementedError()\n");
-      }
-      if (!method->ServerStreaming()) {
-        out->Print(method_dict, "$Method$.future = None\n");
-      }
-    }
-  }
-}
+  if (method->NoStreaming() || method->ServerStreaming())
+    return "self, request, context";
 
-void PrivateGenerator::PrintBetaServerFactory(
-    const grpc::string& package_qualified_service_name,
-    const grpc_generator::Service* service, grpc_generator::Printer* out) {
-  StringMap service_dict;
-  service_dict["Service"] = service->name();
-  out->Print("\n\n");
-  out->Print(service_dict,
-             "def beta_create_$Service$_server(servicer, pool=None, "
-             "pool_size=None, default_timeout=None, maximum_timeout=None):\n");
-  {
-    IndentScope raii_create_server_indent(out);
-    out->Print(
-        "\"\"\"The Beta API is deprecated for 0.15.0 and later.\n"
-        "\nIt is recommended to use the GA API (classes and functions in this\n"
-        "file not marked beta) for all further purposes. This function was\n"
-        "generated only to ease transition from grpcio<0.15.0 to grpcio>=0.15.0"
-        "\"\"\"\n");
-    StringMap method_implementation_constructors;
-    StringMap input_message_modules_and_classes;
-    StringMap output_message_modules_and_classes;
-    for (int i = 0; i < service->method_count(); ++i) {
-      auto method = service->method(i);
-      const grpc::string method_implementation_constructor =
-          grpc::string(method->ClientStreaming() ? "stream_" : "unary_") +
-          grpc::string(method->ServerStreaming() ? "stream_" : "unary_") +
-          "inline";
-      grpc::string input_message_module_and_class = method->get_fb_builder();
-      grpc::string output_message_module_and_class = method->get_fb_builder();
-      method_implementation_constructors.insert(
-          make_pair(method->name(), method_implementation_constructor));
-      input_message_modules_and_classes.insert(
-          make_pair(method->name(), input_message_module_and_class));
-      output_message_modules_and_classes.insert(
-          make_pair(method->name(), output_message_module_and_class));
-    }
-    StringMap method_dict;
-    method_dict["PackageQualifiedServiceName"] = package_qualified_service_name;
-//    out->Print("request_deserializers = {\n");
-//    for (StringMap::iterator name_and_input_module_class_pair =
-//             input_message_modules_and_classes.begin();
-//         name_and_input_module_class_pair !=
-//         input_message_modules_and_classes.end();
-//         name_and_input_module_class_pair++) {
-//      method_dict["MethodName"] = name_and_input_module_class_pair->first;
-//      method_dict["InputTypeModuleAndClass"] =
-//          name_and_input_module_class_pair->second;
-//      IndentScope raii_indent(out);
-//      out->Print(method_dict,
-//                 "(\'$PackageQualifiedServiceName$\', \'$MethodName$\'): "
-//                 "$InputTypeModuleAndClass$.FromString,\n");
-//    }
-//    out->Print("}\n");
-//    out->Print("response_serializers = {\n");
-//    for (StringMap::iterator name_and_output_module_class_pair =
-//             output_message_modules_and_classes.begin();
-//         name_and_output_module_class_pair !=
-//         output_message_modules_and_classes.end();
-//         name_and_output_module_class_pair++) {
-//      method_dict["MethodName"] = name_and_output_module_class_pair->first;
-//      method_dict["OutputTypeModuleAndClass"] =
-//          name_and_output_module_class_pair->second;
-//      IndentScope raii_indent(out);
-//      out->Print(method_dict,
-//                 "(\'$PackageQualifiedServiceName$\', \'$MethodName$\'): "
-//                 "$OutputTypeModuleAndClass$.SerializeToString,\n");
-//    }
-//    out->Print("}\n");
-    out->Print("method_implementations = {\n");
-    for (StringMap::iterator name_and_implementation_constructor =
-             method_implementation_constructors.begin();
-         name_and_implementation_constructor !=
-         method_implementation_constructors.end();
-         name_and_implementation_constructor++) {
-      method_dict["Method"] = name_and_implementation_constructor->first;
-      method_dict["Constructor"] = name_and_implementation_constructor->second;
-      IndentScope raii_descriptions_indent(out);
-      const grpc::string method_name =
-          name_and_implementation_constructor->first;
-      out->Print(method_dict,
-                 "(\'$PackageQualifiedServiceName$\', \'$Method$\'): "
-                 "face_utilities.$Constructor$(servicer.$Method$),\n");
-    }
-    out->Print("}\n");
-    out->Print(
-        "server_options = beta_implementations.server_options("
-        "thread_pool=pool, thread_pool_size=pool_size, "
-        "default_timeout=default_timeout, "
-        "maximum_timeout=maximum_timeout)\n");
-    out->Print(
-        "return beta_implementations.server(method_implementations, "
-        "options=server_options)\n");
-        //"request_deserializers=request_deserializers, "
-        //"response_serializers=response_serializers, "
-  }
+  return "self, request_iterator, context";
 }
 
-void PrivateGenerator::PrintBetaStubFactory(
-    const grpc::string& package_qualified_service_name,
-    const grpc_generator::Service* service, grpc_generator::Printer* out) {
-  StringMap dict;
-  dict["Service"] = service->name();
-  out->Print("\n\n");
-  out->Print(dict,
-             "def beta_create_$Service$_stub(channel, host=None,"
-             " metadata_transformer=None, pool=None, pool_size=None):\n");
-  {
-    IndentScope raii_create_server_indent(out);
-    out->Print(
-        "\"\"\"The Beta API is deprecated for 0.15.0 and later.\n"
-        "\nIt is recommended to use the GA API (classes and functions in this\n"
-        "file not marked beta) for all further purposes. This function was\n"
-        "generated only to ease transition from grpcio<0.15.0 to grpcio>=0.15.0"
-        "\"\"\"\n");
-    StringMap method_cardinalities;
-    StringMap input_message_modules_and_classes;
-    StringMap output_message_modules_and_classes;
-    for (int i = 0; i < service->method_count(); ++i) {
-      auto method = service->method(i);
-      const grpc::string method_cardinality =
-          grpc::string(method->ClientStreaming() ? "STREAM" : "UNARY") +
-          "_" +
-          grpc::string(method->ServerStreaming() ? "STREAM" : "UNARY");
-      grpc::string input_message_module_and_class = method->get_fb_builder();
-      grpc::string output_message_module_and_class = method->get_fb_builder();
-      method_cardinalities.insert(
-          make_pair(method->name(), method_cardinality));
-      input_message_modules_and_classes.insert(
-          make_pair(method->name(), input_message_module_and_class));
-      output_message_modules_and_classes.insert(
-          make_pair(method->name(), output_message_module_and_class));
-    }
-    StringMap method_dict;
-    method_dict["PackageQualifiedServiceName"] = package_qualified_service_name;
-//    out->Print("request_serializers = {\n");
-//    for (StringMap::iterator name_and_input_module_class_pair =
-//             input_message_modules_and_classes.begin();
-//         name_and_input_module_class_pair !=
-//         input_message_modules_and_classes.end();
-//         name_and_input_module_class_pair++) {
-//      method_dict["MethodName"] = name_and_input_module_class_pair->first;
-//      method_dict["InputTypeModuleAndClass"] =
-//          name_and_input_module_class_pair->second;
-//      IndentScope raii_indent(out);
-//      out->Print(method_dict,
-//                 "(\'$PackageQualifiedServiceName$\', \'$MethodName$\'): "
-//                 "$InputTypeModuleAndClass$.SerializeToString,\n");
-//    }
-//    out->Print("}\n");
-//    out->Print("response_deserializers = {\n");
-//    for (StringMap::iterator name_and_output_module_class_pair =
-//             output_message_modules_and_classes.begin();
-//         name_and_output_module_class_pair !=
-//         output_message_modules_and_classes.end();
-//         name_and_output_module_class_pair++) {
-//      method_dict["MethodName"] = name_and_output_module_class_pair->first;
-//      method_dict["OutputTypeModuleAndClass"] =
-//          name_and_output_module_class_pair->second;
-//      IndentScope raii_indent(out);
-//      out->Print(method_dict,
-//                 "(\'$PackageQualifiedServiceName$\', \'$MethodName$\'): "
-//                 "$OutputTypeModuleAndClass$.FromString,\n");
-//    }
-//    out->Print("}\n");
-    out->Print("cardinalities = {\n");
-    for (StringMap::iterator name_and_cardinality =
-             method_cardinalities.begin();
-         name_and_cardinality != method_cardinalities.end();
-         name_and_cardinality++) {
-      method_dict["Method"] = name_and_cardinality->first;
-      method_dict["Cardinality"] = name_and_cardinality->second;
-      IndentScope raii_descriptions_indent(out);
-      out->Print(method_dict,
-                 "\'$Method$\': cardinality.Cardinality.$Cardinality$,\n");
-    }
-    out->Print("}\n");
-    out->Print(
-        "stub_options = beta_implementations.stub_options("
-        "host=host, metadata_transformer=metadata_transformer, "
-        "thread_pool=pool, thread_pool_size=pool_size)\n");
-    out->Print(method_dict,
-               "return beta_implementations.dynamic_stub(channel, "
-               "\'$PackageQualifiedServiceName$\', "
-               "cardinalities, options=stub_options)\n");
-        // "request_serializers=request_serializers, "
-        //"response_deserializers=response_deserializers, "
-  }
-}
+void GenerateStub(const grpc_generator::Service *service,
+                  grpc_generator::Printer *printer,
+                  std::map<grpc::string, grpc::string> *dictonary) {
+  auto vars = *dictonary;
+  printer->Print(vars, "class $ServiceName$Stub(object):\n");
+  printer->Indent();
+  printer->Print("\"\"\" Interface exported by the server. \"\"\"");
+  printer->Print("\n\n");
+  printer->Print("def __init__(self, channel):\n");
+  printer->Indent();
+  printer->Print("\"\"\" Constructor. \n\n");
+  printer->Print("Args: \n");
+  printer->Print("channel: A grpc.Channel. \n");
+  printer->Print("\"\"\"\n\n");
 
-void PrivateGenerator::PrintStub(
-    const grpc::string& package_qualified_service_name,
-    const grpc_generator::Service* service, grpc_generator::Printer* out) {
-  StringMap dict;
-  dict["Service"] = service->name();
-  out->Print("\n\n");
-  out->Print(dict, "class $Service$Stub(object):\n");
-  {
-    IndentScope raii_class_indent(out);
-    out->Print("\n");
-    out->Print("def __init__(self, channel):\n");
-    {
-      IndentScope raii_init_indent(out);
-      out->Print("\"\"\"Constructor.\n");
-      out->Print("\n");
-      out->Print("Args:\n");
-      {
-        IndentScope raii_args_indent(out);
-        out->Print("channel: A grpc.Channel.\n");
-      }
-      out->Print("\"\"\"\n");
-      for (int i = 0; i < service->method_count(); ++i) {
-        auto method = service->method(i);
-        grpc::string multi_callable_constructor =
-            grpc::string(method->ClientStreaming() ? "stream" : "unary") +
-            "_" +
-            grpc::string(method->ServerStreaming() ? "stream" : "unary");
-        grpc::string request_module_and_class = method->get_fb_builder();
-        grpc::string response_module_and_class = method->get_fb_builder();
-        StringMap method_dict;
-        method_dict["Method"] = method->name();
-        method_dict["MultiCallableConstructor"] = multi_callable_constructor;
-        out->Print(method_dict,
-                   "self.$Method$ = channel.$MultiCallableConstructor$(\n");
-        {
-          method_dict["PackageQualifiedService"] =
-              package_qualified_service_name;
-          method_dict["RequestModuleAndClass"] = request_module_and_class;
-          method_dict["ResponseModuleAndClass"] = response_module_and_class;
-          IndentScope raii_first_attribute_indent(out);
-          IndentScope raii_second_attribute_indent(out);
-          out->Print(method_dict, "'/$PackageQualifiedService$/$Method$',\n");
-          out->Print(method_dict,"\n");
-          out->Print(
-              method_dict,"\n");
-          out->Print(")\n");
-        }
-      }
-    }
+  for (int j = 0; j < service->method_count(); j++) {
+    auto method = service->method(j);
+    vars["MethodName"] = method->name();
+    vars["MethodType"] = GenerateMethodType(&*method);
+    printer->Print(vars, "self.$MethodName$ = channel.$MethodType$(\n");
+    printer->Indent();
+    printer->Print(vars, "\"/$PATH$$ServiceName$/$MethodName$\"\n");
+    printer->Print(")\n");
+    printer->Outdent();
+    printer->Print("\n");
   }
-}
-
-void PrivateGenerator::PrintServicer(const grpc_generator::Service* service,
-                                     grpc_generator::Printer* out) {
-  StringMap service_dict;
-  service_dict["Service"] = service->name();
-  out->Print("\n\n");
-  out->Print(service_dict, "class $Service$Servicer(object):\n");
-  {
-    IndentScope raii_class_indent(out);
-    for (int i = 0; i < service->method_count(); ++i) {
-      auto method = service->method(i);
-      grpc::string arg_name =
-          method->ClientStreaming() ? "request_iterator" : "request";
-      StringMap method_dict;
-      method_dict["Method"] = method->name();
-      method_dict["ArgName"] = arg_name;
-      out->Print("\n");
-      out->Print(method_dict, "def $Method$(self, $ArgName$, context):\n");
-      {
-        IndentScope raii_method_indent(out);
-        out->Print("context.set_code(grpc.StatusCode.UNIMPLEMENTED)\n");
-        out->Print("context.set_details('Method not implemented!')\n");
-        out->Print("raise NotImplementedError('Method not implemented!')\n");
-      }
-    }
+  printer->Outdent();
+  printer->Outdent();
+  printer->Print("\n");
+}
+
+void GenerateServicer(const grpc_generator::Service *service,
+                      grpc_generator::Printer *printer,
+                      std::map<grpc::string, grpc::string> *dictonary) {
+  auto vars = *dictonary;
+  printer->Print(vars, "class $ServiceName$Servicer(object):\n");
+  printer->Indent();
+  printer->Print("\"\"\" Interface exported by the server. \"\"\"");
+  printer->Print("\n\n");
+
+  for (int j = 0; j < service->method_count(); j++) {
+    auto method = service->method(j);
+    vars["MethodName"] = method->name();
+    vars["MethodInput"] = GenerateMethodInput(&*method);
+    printer->Print(vars, "def $MethodName$($MethodInput$):\n");
+    printer->Indent();
+    printer->Print("context.set_code(grpc.StatusCode.UNIMPLEMENTED)\n");
+    printer->Print("context.set_details('Method not implemented!')\n");
+    printer->Print("raise NotImplementedError('Method not implemented!')\n");
+    printer->Outdent();
+    printer->Print("\n\n");
   }
-}
-
-void PrivateGenerator::PrintAddServicerToServer(
-    const grpc::string& package_qualified_service_name,
-    const grpc_generator::Service* service, grpc_generator::Printer* out) {
-  StringMap service_dict;
-  service_dict["Service"] = service->name();
-  out->Print("\n\n");
-  out->Print(service_dict,
-             "def add_$Service$Servicer_to_server(servicer, server):\n");
-  {
-    IndentScope raii_class_indent(out);
-    out->Print("rpc_method_handlers = {\n");
-    {
-      IndentScope raii_dict_first_indent(out);
-      IndentScope raii_dict_second_indent(out);
-      for (int i = 0; i < service->method_count(); ++i) {
-        auto method = service->method(i);
-        grpc::string method_handler_constructor =
-            grpc::string(method->ClientStreaming() ? "stream" : "unary") +
-            "_" +
-            grpc::string(method->ServerStreaming() ? "stream" : "unary") +
-            "_rpc_method_handler";
-        grpc::string request_module_and_class = method->get_fb_builder();
-        grpc::string response_module_and_class = method->get_fb_builder();
-        StringMap method_dict;
-        method_dict["Method"] = method->name();
-        method_dict["MethodHandlerConstructor"] = method_handler_constructor;
-        method_dict["RequestModuleAndClass"] = request_module_and_class;
-        method_dict["ResponseModuleAndClass"] = response_module_and_class;
-        out->Print(method_dict,
-                   "'$Method$': grpc.$MethodHandlerConstructor$(\n");
-        {
-          IndentScope raii_call_first_indent(out);
-          IndentScope raii_call_second_indent(out);
-          out->Print(method_dict, "servicer.$Method$,\n");
-          out->Print(
-              method_dict,"\n");
-          out->Print(
-              method_dict,
-              "\n");
-        }
-        out->Print("),\n");
-      }
-    }
-    StringMap method_dict;
-    method_dict["PackageQualifiedServiceName"] = package_qualified_service_name;
-    out->Print("}\n");
-    out->Print("generic_handler = grpc.method_handlers_generic_handler(\n");
-    {
-      IndentScope raii_call_first_indent(out);
-      IndentScope raii_call_second_indent(out);
-      out->Print(method_dict,
-                 "'$PackageQualifiedServiceName$', rpc_method_handlers)\n");
-    }
-    out->Print("server.add_generic_rpc_handlers((generic_handler,))\n");
+  printer->Outdent();
+  printer->Print("\n");
+
+}
+
+void GenerateRegister(const grpc_generator::Service *service,
+                      grpc_generator::Printer *printer,
+                      std::map<grpc::string, grpc::string> *dictonary) {
+  auto vars = *dictonary;
+  printer->Print(vars, "def add_$ServiceName$Servicer_to_server(servicer, server):\n");
+  printer->Indent();
+  printer->Print("rpc_method_handlers = {\n");
+  printer->Indent();
+  for (int j = 0; j < service->method_count(); j++) {
+    auto method = service->method(j);
+    vars["MethodName"] = method->name();
+    vars["MethodType"] = GenerateMethodType(&*method);
+    printer->Print(vars, "'$MethodName$': grpc.$MethodType$_rpc_method_handler(\n");
+    printer->Indent();
+    printer->Print(vars, "servicer.$MethodName$\n");
+    printer->Outdent();
+    printer->Print("),\n");
   }
-}
-
-void PrivateGenerator::PrintBetaPreamble(grpc_generator::Printer* out) {
-  StringMap var;
-  var["Package"] = config.beta_package_root;
-  out->Print(var,
-             "from $Package$ import implementations as beta_implementations\n");
-  out->Print(var, "from $Package$ import interfaces as beta_interfaces\n");
-  out->Print("from grpc.framework.common import cardinality\n");
-  out->Print(
-      "from grpc.framework.interfaces.face import utilities as "
-      "face_utilities\n");
-}
-
-void PrivateGenerator::PrintPreamble(grpc_generator::Printer* out) {
-  StringMap var;
-  var["Package"] = config.grpc_package_root;
-  out->Print(var, "import $Package$\n");
-  out->Print("\n");
-  StringPairSet imports_set;
-  for (int i = 0; i < file->service_count(); ++i) {
-    auto service = file->service(i);
-    for (int j = 0; j < service->method_count(); ++j) {
-      auto method = service.get()->method(j);
-
-      grpc::string input_type_file_name = method->get_fb_builder();
-      grpc::string input_module_name =
-          ModuleName(input_type_file_name, config.import_prefix);
-      grpc::string input_module_alias =
-          ModuleAlias(input_type_file_name, config.import_prefix);
-      imports_set.insert(
-          std::make_tuple(input_module_name, input_module_alias));
-
-      grpc::string output_type_file_name = method->get_fb_builder();
-      grpc::string output_module_name =
-          ModuleName(output_type_file_name, config.import_prefix);
-      grpc::string output_module_alias =
-          ModuleAlias(output_type_file_name, config.import_prefix);
-      imports_set.insert(
-          std::make_tuple(output_module_name, output_module_alias));
-    }
-  }
-
-  for (StringPairSet::iterator it = imports_set.begin();
-       it != imports_set.end(); ++it) {
-    var["ModuleName"] = std::get<0>(*it);
-    var["ModuleAlias"] = std::get<1>(*it);
-    out->Print(var, "import $ModuleName$ as $ModuleAlias$\n");
-  }
-}
-
-void PrivateGenerator::PrintGAServices(grpc_generator::Printer* out) {
-  grpc::string package = file->package();
-  if (!package.empty()) {
-    package = package.append(".");
-  }
-
-  out->Print(file->additional_headers().c_str());
-
-  for (int i = 0; i < file->service_count(); ++i) {
-    auto service = file->service(i);
-
-    grpc::string package_qualified_service_name = package + service->name();
-    PrintStub(package_qualified_service_name, service.get(), out);
-    PrintServicer(service.get(), out);
-    PrintAddServicerToServer(package_qualified_service_name, service.get(),
-                             out);
-  }
-}
-
-void PrivateGenerator::PrintBetaServices(grpc_generator::Printer* out) {
-  grpc::string package = file->package();
-  if (!package.empty()) {
-    package = package.append(".");
-  }
-  for (int i = 0; i < file->service_count(); ++i) {
-    auto service = file->service(i);
-
-    grpc::string package_qualified_service_name = package + service->name();
-    PrintBetaServicer(service.get(), out);
-    PrintBetaStub(service.get(), out);
-    PrintBetaServerFactory(package_qualified_service_name, service.get(), out);
-    PrintBetaStubFactory(package_qualified_service_name, service.get(), out);
-  }
-}
-
-grpc::string PrivateGenerator::GetGrpcServices() {
+  printer->Outdent();
+  printer->Print("}\n");
+  printer->Print(vars, "generic_handler = grpc.method_handlers_generic_handler(\n");
+  printer->Indent();
+  printer->Print(vars, "'$PATH$$ServiceName$', rpc_method_handlers)\n");
+  printer->Outdent();
+  printer->Print("server.add_generic_rpc_handlers((generic_handler,))");
+  printer->Outdent();
+  printer->Print("\n");
+}
+
+grpc::string Generate(grpc_generator::File *file,
+                      const grpc_generator::Service *service) {
   grpc::string output;
-  {
-    // Scope the output stream so it closes and finalizes output to the string.
-    auto out = file->CreatePrinter(&output);
-    out->Print(
-        "# Generated by the gRPC Python protocol compiler plugin. "
-        "DO NOT EDIT!\n");
-    StringMap var;
-    var["Package"] = config.grpc_package_root;
-    out->Print(var, "import $Package$\n");
-    PrintGAServices(out.get());
-    out->Print("try:\n");
-    {
-      IndentScope raii_dict_try_indent(out.get());
-      out->Print(
-          "# THESE ELEMENTS WILL BE DEPRECATED.\n"
-          "# Please use the generated *_pb2_grpc.py files instead.\n");
-      out->Print(var, "import $Package$\n");
-      PrintBetaPreamble(out.get());
-      PrintGAServices(out.get());
-      PrintBetaServices(out.get());
-    }
-    out->Print("except ImportError:\n");
-    {
-      IndentScope raii_dict_except_indent(out.get());
-      out->Print("pass");
-    }
-  }
+  std::map<grpc::string, grpc::string> vars;
+  vars["PATH"] = file->package();
+  if (!file->package().empty()) { vars["PATH"].append("."); }
+  vars["ServiceName"] = service->name();
+  auto printer = file->CreatePrinter(&output);
+  GenerateStub(service, &*printer, &vars);
+  GenerateServicer(service, &*printer, &vars);
+  GenerateRegister(service, &*printer, &vars);
   return output;
 }
 
diff --git a/grpc/src/compiler/python_generator.h b/grpc/src/compiler/python_generator.h
index d92cb025..4f8f5cc8 100644
--- a/grpc/src/compiler/python_generator.h
+++ b/grpc/src/compiler/python_generator.h
@@ -21,20 +21,13 @@
 
 #include <utility>
 
+#include "src/compiler/config.h"
 #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;
-};
-
+grpc::string Generate(grpc_generator::File *file,
+                      const grpc_generator::Service *service);
 }  // namespace grpc_python_generator
 
 #endif  // GRPC_INTERNAL_COMPILER_PYTHON_GENERATOR_H
diff --git a/grpc/src/compiler/python_private_generator.h b/grpc/src/compiler/python_private_generator.h
deleted file mode 100644
index 30ba0d7b..00000000
--- a/grpc/src/compiler/python_private_generator.h
+++ /dev/null
@@ -1,72 +0,0 @@
-/*
- *
- * Copyright 2015 gRPC 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.
- *
- */
-
-#ifndef GRPC_INTERNAL_COMPILER_PYTHON_PRIVATE_GENERATOR_H
-#define GRPC_INTERNAL_COMPILER_PYTHON_PRIVATE_GENERATOR_H
-
-#include <iostream>
-#include <vector>
-
-#include "src/compiler/python_generator.h"
-#include "src/compiler/schema_interface.h"
-
-namespace grpc_python_generator {
-
-// Tucks all generator state in an anonymous namespace away from
-// PythonGrpcGenerator and the header file, mostly to encourage future changes
-// to not require updates to the grpcio-tools C++ code part. Assumes that it is
-// only ever used from a single thread.
-struct PrivateGenerator {
-  const GeneratorConfiguration& config;
-  const grpc_generator::File* file;
-
-  PrivateGenerator(const GeneratorConfiguration& config,
-                   const grpc_generator::File* file);
-
-  grpc::string GetGrpcServices();
-
- private:
-  void PrintPreamble(grpc_generator::Printer* out);
-  void PrintBetaPreamble(grpc_generator::Printer* out);
-  void PrintGAServices(grpc_generator::Printer* out);
-  void PrintBetaServices(grpc_generator::Printer* out);
-
-  void PrintAddServicerToServer(
-      const grpc::string& package_qualified_service_name,
-      const grpc_generator::Service* service, grpc_generator::Printer* out);
-  void PrintServicer(const grpc_generator::Service* service,
-                     grpc_generator::Printer* out);
-  void PrintStub(const grpc::string& package_qualified_service_name,
-                 const grpc_generator::Service* service,
-                 grpc_generator::Printer* out);
-
-  void PrintBetaServicer(const grpc_generator::Service* service,
-                         grpc_generator::Printer* out);
-  void PrintBetaServerFactory(
-      const grpc::string& package_qualified_service_name,
-      const grpc_generator::Service* service, grpc_generator::Printer* out);
-  void PrintBetaStub(const grpc_generator::Service* service,
-                     grpc_generator::Printer* out);
-  void PrintBetaStubFactory(const grpc::string& package_qualified_service_name,
-                            const grpc_generator::Service* service,
-                            grpc_generator::Printer* out);
-};
-
-}  // namespace grpc_python_generator
-
-#endif  // GRPC_INTERNAL_COMPILER_PYTHON_PRIVATE_GENERATOR_H
diff --git a/src/idl_gen_grpc.cpp b/src/idl_gen_grpc.cpp
index 9beb10c5..9aea745d 100644
--- a/src/idl_gen_grpc.cpp
+++ b/src/idl_gen_grpc.cpp
@@ -24,7 +24,6 @@
 #include "src/compiler/go_generator.h"
 #include "src/compiler/java_generator.h"
 #include "src/compiler/python_generator.h"
-#include "src/compiler/python_private_generator.h"
 #include "src/compiler/swift_generator.h"
 #include "src/compiler/ts_generator.h"
 
@@ -412,6 +411,45 @@ bool GenerateJavaGRPC(const Parser &parser, const std::string &path,
   return JavaGRPCGenerator(parser, path, file_name).generate();
 }
 
+class PythonGRPCGenerator : public flatbuffers::BaseGenerator {
+ private:
+  CodeWriter code_;
+
+ public:
+  PythonGRPCGenerator(const Parser &parser, const std::string &filename)
+      : BaseGenerator(parser, "", filename, "", "" /*Unused*/, "swift") {}
+
+  bool generate() {
+    code_.Clear();
+    code_ +=
+        "# Generated by the gRPC Python protocol compiler plugin. "
+        "DO NOT EDIT!\n";
+    code_ += "import grpc\n";
+
+    FlatBufFile file(parser_, file_name_, FlatBufFile::kLanguagePython);
+
+    for (int i = 0; i < file.service_count(); i++) {
+      auto service = file.service(i);
+      code_ += grpc_python_generator::Generate(&file, service.get());
+    }
+    const auto final_code = code_.ToString();
+    const auto filename = GenerateFileName();
+    return SaveFile(filename.c_str(), final_code, false);
+  }
+
+  std::string GenerateFileName() {
+    std::string namespace_dir;
+    auto &namespaces = parser_.namespaces_.back()->components;
+    for (auto it = namespaces.begin(); it != namespaces.end(); ++it) {
+      if (it != namespaces.begin()) namespace_dir += kPathSeparator;
+      namespace_dir += *it;
+    }
+    std::string grpc_py_filename = namespace_dir;
+    if (!namespace_dir.empty()) grpc_py_filename += kPathSeparator;
+    return grpc_py_filename + file_name_ + "_grpc_fb.py";
+  }
+};
+
 bool GeneratePythonGRPC(const Parser &parser, const std::string & /*path*/,
                         const std::string &file_name) {
   int nservices = 0;
@@ -421,28 +459,7 @@ bool GeneratePythonGRPC(const Parser &parser, const std::string & /*path*/,
   }
   if (!nservices) return true;
 
-  grpc_python_generator::GeneratorConfiguration config;
-  config.grpc_package_root = "grpc";
-  config.beta_package_root = "grpc.beta";
-  config.import_prefix = "";
-
-  FlatBufFile fbfile(parser, file_name, FlatBufFile::kLanguagePython);
-
-  grpc_python_generator::PrivateGenerator generator(config, &fbfile);
-
-  std::string code = generator.GetGrpcServices();
-  std::string namespace_dir;
-  auto &namespaces = parser.namespaces_.back()->components;
-  for (auto it = namespaces.begin(); it != namespaces.end(); ++it) {
-    if (it != namespaces.begin()) namespace_dir += kPathSeparator;
-    namespace_dir += *it;
-  }
-
-  std::string grpc_py_filename = namespace_dir;
-  if (!namespace_dir.empty()) grpc_py_filename += kPathSeparator;
-  grpc_py_filename += file_name + "_grpc_fb.py";
-
-  return flatbuffers::SaveFile(grpc_py_filename.c_str(), code, false);
+  return PythonGRPCGenerator(parser, file_name).generate();
 }
 
 class SwiftGRPCGenerator : public flatbuffers::BaseGenerator {