src/compiler/python_generator.cc - platform/external/grpc-grpc - Git at Google

 /*
  *
  * 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.
  *
  */

 #include <cassert>
 #include <cctype>
 #include <cstring>
 #include <map>
 #include <ostream>
 #include <sstream>
 #include <vector>

 #include "src/compiler/python_generator.h"
 #include <google/protobuf/io/printer.h>
 #include <google/protobuf/io/zero_copy_stream_impl_lite.h>
 #include <google/protobuf/descriptor.pb.h>
 #include <google/protobuf/descriptor.h>

 using google::protobuf::Descriptor;
 using google::protobuf::FileDescriptor;
 using google::protobuf::ServiceDescriptor;
 using google::protobuf::MethodDescriptor;
 using google::protobuf::io::Printer;
 using google::protobuf::io::StringOutputStream;
 using std::initializer_list;
 using std::make_pair;
 using std::map;
 using std::pair;
 using std::string;
 using std::strlen;
 using std::vector;

 namespace grpc_python_generator {
 namespace {
 //////////////////////////////////
 // BEGIN FORMATTING BOILERPLATE //
 //////////////////////////////////

 // Converts an initializer list of the form { key0, value0, key1, value1, ... }
 // into a map of key* to value*. Is merely a readability helper for later code.
 map<string, string> ListToDict(const initializer_list<string>& values) {
   assert(values.size() % 2 == 0);
   map<string, string> value_map;
   auto value_iter = values.begin();
   for (unsigned i = 0; i < values.size()/2; ++i) {
     string key = *value_iter;
     ++value_iter;
     string value = *value_iter;
     value_map[key] = value;
     ++value_iter;
   }
   return value_map;
 }

 // 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(Printer* printer) : printer_(printer) {
     printer_->Indent();
   }

   ~IndentScope() {
     printer_->Outdent();
   }

  private:
   Printer* printer_;
 };

 ////////////////////////////////
 // END FORMATTING BOILERPLATE //
 ////////////////////////////////

 bool PrintServicer(const ServiceDescriptor* service,
                    Printer* out) {
   string doc = "<fill me in later!>";
   map<string, string> dict = ListToDict({
         "Service", service->name(),
         "Documentation", doc,
       });
   out->Print(dict, "class EarlyAdopter$Service$Servicer(object):\n");
   {
     IndentScope raii_class_indent(out);
     out->Print(dict, "\"\"\"$Documentation$\"\"\"\n");
     out->Print("__metaclass__ = abc.ABCMeta\n");
     for (int i = 0; i < service->method_count(); ++i) {
       auto meth = service->method(i);
       string arg_name = meth->client_streaming() ?
           "request_iterator" : "request";
       out->Print("@abc.abstractmethod\n");
       out->Print("def $Method$(self, $ArgName$):\n",
                  "Method", meth->name(), "ArgName", arg_name);
       {
         IndentScope raii_method_indent(out);
         out->Print("raise NotImplementedError()\n");
       }
     }
   }
   return true;
 }

 bool PrintServer(const ServiceDescriptor* service, Printer* out) {
   string doc = "<fill me in later!>";
   map<string, string> dict = ListToDict({
         "Service", service->name(),
         "Documentation", doc,
       });
   out->Print(dict, "class EarlyAdopter$Service$Server(object):\n");
   {
     IndentScope raii_class_indent(out);
     out->Print(dict, "\"\"\"$Documentation$\"\"\"\n");
     out->Print("__metaclass__ = abc.ABCMeta\n");
     out->Print("@abc.abstractmethod\n");
     out->Print("def start(self):\n");
     {
       IndentScope raii_method_indent(out);
       out->Print("raise NotImplementedError()\n");
     }

     out->Print("@abc.abstractmethod\n");
     out->Print("def stop(self):\n");
     {
       IndentScope raii_method_indent(out);
       out->Print("raise NotImplementedError()\n");
     }
   }
   return true;
 }

 bool PrintStub(const ServiceDescriptor* service,
                Printer* out) {
   string doc = "<fill me in later!>";
   map<string, string> dict = ListToDict({
         "Service", service->name(),
         "Documentation", doc,
       });
   out->Print(dict, "class EarlyAdopter$Service$Stub(object):\n");
   {
     IndentScope raii_class_indent(out);
     out->Print(dict, "\"\"\"$Documentation$\"\"\"\n");
     out->Print("__metaclass__ = abc.ABCMeta\n");
     for (int i = 0; i < service->method_count(); ++i) {
       const MethodDescriptor* meth = service->method(i);
       string arg_name = meth->client_streaming() ?
           "request_iterator" : "request";
       auto methdict = ListToDict({"Method", meth->name(), "ArgName", arg_name});
       out->Print("@abc.abstractmethod\n");
       out->Print(methdict, "def $Method$(self, $ArgName$):\n");
       {
         IndentScope raii_method_indent(out);
         out->Print("raise NotImplementedError()\n");
       }
       out->Print(methdict, "$Method$.async = None\n");
     }
   }
   return true;
 }

 bool GetModuleAndMessagePath(const Descriptor* type,
                              pair<string, string>* out) {
   const Descriptor* path_elem_type = type;
   vector<const Descriptor*> message_path;
   do {
     message_path.push_back(path_elem_type);
     path_elem_type = path_elem_type->containing_type();
   } while (path_elem_type != nullptr);
   string file_name = type->file()->name();
   string module_name;
   static const int proto_suffix_length = strlen(".proto");
   if (!(file_name.size() > static_cast<size_t>(proto_suffix_length) &&
         file_name.find_last_of(".proto") == file_name.size() - 1)) {
     return false;
   }
   module_name = file_name.substr(
       0, file_name.size() - proto_suffix_length) + "_pb2";
   string package = type->file()->package();
   string module = (package.empty() ? "" : package + ".") +
       module_name;
   string message_type;
   for (auto path_iter = message_path.rbegin();
        path_iter != message_path.rend(); ++path_iter) {
     message_type += (*path_iter)->name() + ".";
   }
   message_type.pop_back();
   *out = make_pair(module, message_type);
   return true;
 }

 bool PrintServerFactory(const ServiceDescriptor* service, Printer* out) {
   out->Print("def early_adopter_create_$Service$_server(servicer, port, "
              "root_certificates, key_chain_pairs):\n",
              "Service", service->name());
   {
     IndentScope raii_create_server_indent(out);
     map<string, pair<string, string>> method_to_module_and_message;
     out->Print("method_implementations = {\n");
     for (int i = 0; i < service->method_count(); ++i) {
       IndentScope raii_implementations_indent(out);
       const MethodDescriptor* meth = service->method(i);
       string meth_type =
           string(meth->client_streaming() ? "stream" : "unary") +
           string(meth->server_streaming() ? "_stream" : "_unary") + "_inline";
       out->Print("\"$Method$\": utilities.$Type$(servicer.$Method$),\n",
                  "Method", meth->name(),
                  "Type", meth_type);
       // Maintain information on the input type of the service method for later
       // use in constructing the service assembly's activated fore link.
       const Descriptor* input_type = meth->input_type();
       pair<string, string> module_and_message;
       if (!GetModuleAndMessagePath(input_type, &module_and_message)) {
         return false;
       }
       method_to_module_and_message.insert(
           make_pair(meth->name(), module_and_message));
     }
     out->Print("}\n");
     // Ensure that we've imported all of the relevant messages.
     for (auto& meth_vals : method_to_module_and_message) {
       out->Print("import $Module$\n",
                  "Module", meth_vals.second.first);
     }
     out->Print("request_deserializers = {\n");
     for (auto& meth_vals : method_to_module_and_message) {
       IndentScope raii_serializers_indent(out);
       string full_input_type_path = meth_vals.second.first + "." +
           meth_vals.second.second;
       out->Print("\"$Method$\": $Type$.FromString,\n",
                  "Method", meth_vals.first,
                  "Type", full_input_type_path);
     }
     out->Print("}\n");
     out->Print("response_serializers = {\n");
     for (auto& meth_vals : method_to_module_and_message) {
       IndentScope raii_serializers_indent(out);
       out->Print("\"$Method$\": lambda x: x.SerializeToString(),\n",
                  "Method", meth_vals.first);
     }
     out->Print("}\n");
     out->Print("link = fore.activated_fore_link(port, request_deserializers, "
                "response_serializers, root_certificates, key_chain_pairs)\n");
     out->Print("return implementations.assemble_service("
                "method_implementations, link)\n");
   }
   return true;
 }

 bool PrintStubFactory(const ServiceDescriptor* service, Printer* out) {
   map<string, string> dict = ListToDict({
         "Service", service->name(),
       });
   out->Print(dict, "def early_adopter_create_$Service$_stub(host, port):\n");
   {
     IndentScope raii_create_server_indent(out);
     map<string, pair<string, string>> method_to_module_and_message;
     out->Print("method_implementations = {\n");
     for (int i = 0; i < service->method_count(); ++i) {
       IndentScope raii_implementations_indent(out);
       const MethodDescriptor* meth = service->method(i);
       string meth_type =
           string(meth->client_streaming() ? "stream" : "unary") +
           string(meth->server_streaming() ? "_stream" : "_unary") + "_inline";
       // TODO(atash): once the expected input to assemble_dynamic_inline_stub is
       // cleaned up, change this to the expected argument's dictionary values.
       out->Print("\"$Method$\": utilities.$Type$(None),\n",
                  "Method", meth->name(),
                  "Type", meth_type);
       // Maintain information on the input type of the service method for later
       // use in constructing the service assembly's activated fore link.
       const Descriptor* output_type = meth->output_type();
       pair<string, string> module_and_message;
       if (!GetModuleAndMessagePath(output_type, &module_and_message)) {
         return false;
       }
       method_to_module_and_message.insert(
           make_pair(meth->name(), module_and_message));
     }
     out->Print("}\n");
     // Ensure that we've imported all of the relevant messages.
     for (auto& meth_vals : method_to_module_and_message) {
       out->Print("import $Module$\n",
                  "Module", meth_vals.second.first);
     }
     out->Print("response_deserializers = {\n");
     for (auto& meth_vals : method_to_module_and_message) {
       IndentScope raii_serializers_indent(out);
       string full_output_type_path = meth_vals.second.first + "." +
           meth_vals.second.second;
       out->Print("\"$Method$\": $Type$.FromString,\n",
                  "Method", meth_vals.first,
                  "Type", full_output_type_path);
     }
     out->Print("}\n");
     out->Print("request_serializers = {\n");
     for (auto& meth_vals : method_to_module_and_message) {
       IndentScope raii_serializers_indent(out);
       out->Print("\"$Method$\": lambda x: x.SerializeToString(),\n",
                  "Method", meth_vals.first);
     }
     out->Print("}\n");
     out->Print("link = rear.activated_rear_link("
                "host, port, request_serializers, response_deserializers)\n");
     out->Print("return implementations.assemble_dynamic_inline_stub("
                "method_implementations, link)\n");
   }
   return true;
 }

 bool PrintPreamble(const FileDescriptor* file, Printer* out) {
   out->Print("import abc\n");
   out->Print("from grpc._adapter import fore\n");
   out->Print("from grpc._adapter import rear\n");
   out->Print("from grpc.framework.assembly import implementations\n");
   out->Print("from grpc.framework.assembly import utilities\n");
   return true;
 }

 }  // namespace

 pair<bool, string> GetServices(const FileDescriptor* file) {
   string output;
   {
     // Scope the output stream so it closes and finalizes output to the string.
     StringOutputStream output_stream(&output);
     Printer out(&output_stream, '$');
     if (!PrintPreamble(file, &out)) {
       return make_pair(false, "");
     }
     for (int i = 0; i < file->service_count(); ++i) {
       auto service = file->service(i);
       if (!(PrintServicer(service, &out) &&
             PrintServer(service, &out) &&
             PrintStub(service, &out) &&
             PrintServerFactory(service, &out) &&
             PrintStubFactory(service, &out))) {
         return make_pair(false, "");
       }
     }
   }
   return make_pair(true, std::move(output));
 }

 }  // namespace grpc_python_generator
	/*
	*
	* 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.
	*
	*/

	#include <cassert>
	#include <cctype>
	#include <cstring>
	#include <map>
	#include <ostream>
	#include <sstream>
	#include <vector>

	#include "src/compiler/python_generator.h"
	#include <google/protobuf/io/printer.h>
	#include <google/protobuf/io/zero_copy_stream_impl_lite.h>
	#include <google/protobuf/descriptor.pb.h>
	#include <google/protobuf/descriptor.h>

	using google::protobuf::Descriptor;
	using google::protobuf::FileDescriptor;
	using google::protobuf::ServiceDescriptor;
	using google::protobuf::MethodDescriptor;
	using google::protobuf::io::Printer;
	using google::protobuf::io::StringOutputStream;
	using std::initializer_list;
	using std::make_pair;
	using std::map;
	using std::pair;
	using std::string;
	using std::strlen;
	using std::vector;

	namespace grpc_python_generator {
	namespace {
	//////////////////////////////////
	// BEGIN FORMATTING BOILERPLATE //
	//////////////////////////////////

	// Converts an initializer list of the form { key0, value0, key1, value1, ... }
	// into a map of key* to value*. Is merely a readability helper for later code.
	map<string, string> ListToDict(const initializer_list<string>& values) {
	assert(values.size() % 2 == 0);
	map<string, string> value_map;
	auto value_iter = values.begin();
	for (unsigned i = 0; i < values.size()/2; ++i) {
	string key = *value_iter;
	++value_iter;
	string value = *value_iter;
	value_map[key] = value;
	++value_iter;
	}
	return value_map;
	}

	// 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(Printer* printer) : printer_(printer) {
	printer_->Indent();
	}

	~IndentScope() {
	printer_->Outdent();
	}

	private:
	Printer* printer_;
	};

	////////////////////////////////
	// END FORMATTING BOILERPLATE //
	////////////////////////////////

	bool PrintServicer(const ServiceDescriptor* service,
	Printer* out) {
	string doc = "<fill me in later!>";
	map<string, string> dict = ListToDict({
	"Service", service->name(),
	"Documentation", doc,
	});
	out->Print(dict, "class EarlyAdopter$Service$Servicer(object):\n");
	{
	IndentScope raii_class_indent(out);
	out->Print(dict, "\"\"\"$Documentation$\"\"\"\n");
	out->Print("__metaclass__ = abc.ABCMeta\n");
	for (int i = 0; i < service->method_count(); ++i) {
	auto meth = service->method(i);
	string arg_name = meth->client_streaming() ?
	"request_iterator" : "request";
	out->Print("@abc.abstractmethod\n");
	out->Print("def $Method$(self, $ArgName$):\n",
	"Method", meth->name(), "ArgName", arg_name);
	{
	IndentScope raii_method_indent(out);
	out->Print("raise NotImplementedError()\n");
	}
	}
	}
	return true;
	}

	bool PrintServer(const ServiceDescriptor* service, Printer* out) {
	string doc = "<fill me in later!>";
	map<string, string> dict = ListToDict({
	"Service", service->name(),
	"Documentation", doc,
	});
	out->Print(dict, "class EarlyAdopter$Service$Server(object):\n");
	{
	IndentScope raii_class_indent(out);
	out->Print(dict, "\"\"\"$Documentation$\"\"\"\n");
	out->Print("__metaclass__ = abc.ABCMeta\n");
	out->Print("@abc.abstractmethod\n");
	out->Print("def start(self):\n");
	{
	IndentScope raii_method_indent(out);
	out->Print("raise NotImplementedError()\n");
	}

	out->Print("@abc.abstractmethod\n");
	out->Print("def stop(self):\n");
	{
	IndentScope raii_method_indent(out);
	out->Print("raise NotImplementedError()\n");
	}
	}
	return true;
	}

	bool PrintStub(const ServiceDescriptor* service,
	Printer* out) {
	string doc = "<fill me in later!>";
	map<string, string> dict = ListToDict({
	"Service", service->name(),
	"Documentation", doc,
	});
	out->Print(dict, "class EarlyAdopter$Service$Stub(object):\n");
	{
	IndentScope raii_class_indent(out);
	out->Print(dict, "\"\"\"$Documentation$\"\"\"\n");
	out->Print("__metaclass__ = abc.ABCMeta\n");
	for (int i = 0; i < service->method_count(); ++i) {
	const MethodDescriptor* meth = service->method(i);
	string arg_name = meth->client_streaming() ?
	"request_iterator" : "request";
	auto methdict = ListToDict({"Method", meth->name(), "ArgName", arg_name});
	out->Print("@abc.abstractmethod\n");
	out->Print(methdict, "def $Method$(self, $ArgName$):\n");
	{
	IndentScope raii_method_indent(out);
	out->Print("raise NotImplementedError()\n");
	}
	out->Print(methdict, "$Method$.async = None\n");
	}
	}
	return true;
	}

	bool GetModuleAndMessagePath(const Descriptor* type,
	pair<string, string>* out) {
	const Descriptor* path_elem_type = type;
	vector<const Descriptor*> message_path;
	do {
	message_path.push_back(path_elem_type);
	path_elem_type = path_elem_type->containing_type();
	} while (path_elem_type != nullptr);
	string file_name = type->file()->name();
	string module_name;
	static const int proto_suffix_length = strlen(".proto");
	if (!(file_name.size() > static_cast<size_t>(proto_suffix_length) &&
	file_name.find_last_of(".proto") == file_name.size() - 1)) {
	return false;
	}
	module_name = file_name.substr(
	0, file_name.size() - proto_suffix_length) + "_pb2";
	string package = type->file()->package();
	string module = (package.empty() ? "" : package + ".") +
	module_name;
	string message_type;
	for (auto path_iter = message_path.rbegin();
	path_iter != message_path.rend(); ++path_iter) {
	message_type += (*path_iter)->name() + ".";
	}
	message_type.pop_back();
	*out = make_pair(module, message_type);
	return true;
	}

	bool PrintServerFactory(const ServiceDescriptor* service, Printer* out) {
	out->Print("def early_adopter_create_$Service$_server(servicer, port, "
	"root_certificates, key_chain_pairs):\n",
	"Service", service->name());
	{
	IndentScope raii_create_server_indent(out);
	map<string, pair<string, string>> method_to_module_and_message;
	out->Print("method_implementations = {\n");
	for (int i = 0; i < service->method_count(); ++i) {
	IndentScope raii_implementations_indent(out);
	const MethodDescriptor* meth = service->method(i);
	string meth_type =
	string(meth->client_streaming() ? "stream" : "unary") +
	string(meth->server_streaming() ? "_stream" : "_unary") + "_inline";
	out->Print("\"$Method$\": utilities.$Type$(servicer.$Method$),\n",
	"Method", meth->name(),
	"Type", meth_type);
	// Maintain information on the input type of the service method for later
	// use in constructing the service assembly's activated fore link.
	const Descriptor* input_type = meth->input_type();
	pair<string, string> module_and_message;
	if (!GetModuleAndMessagePath(input_type, &module_and_message)) {
	return false;
	}
	method_to_module_and_message.insert(
	make_pair(meth->name(), module_and_message));
	}
	out->Print("}\n");
	// Ensure that we've imported all of the relevant messages.
	for (auto& meth_vals : method_to_module_and_message) {
	out->Print("import $Module$\n",
	"Module", meth_vals.second.first);
	}
	out->Print("request_deserializers = {\n");
	for (auto& meth_vals : method_to_module_and_message) {
	IndentScope raii_serializers_indent(out);
	string full_input_type_path = meth_vals.second.first + "." +
	meth_vals.second.second;
	out->Print("\"$Method$\": $Type$.FromString,\n",
	"Method", meth_vals.first,
	"Type", full_input_type_path);
	}
	out->Print("}\n");
	out->Print("response_serializers = {\n");
	for (auto& meth_vals : method_to_module_and_message) {
	IndentScope raii_serializers_indent(out);
	out->Print("\"$Method$\": lambda x: x.SerializeToString(),\n",
	"Method", meth_vals.first);
	}
	out->Print("}\n");
	out->Print("link = fore.activated_fore_link(port, request_deserializers, "
	"response_serializers, root_certificates, key_chain_pairs)\n");
	out->Print("return implementations.assemble_service("
	"method_implementations, link)\n");
	}
	return true;
	}

	bool PrintStubFactory(const ServiceDescriptor* service, Printer* out) {
	map<string, string> dict = ListToDict({
	"Service", service->name(),
	});
	out->Print(dict, "def early_adopter_create_$Service$_stub(host, port):\n");
	{
	IndentScope raii_create_server_indent(out);
	map<string, pair<string, string>> method_to_module_and_message;
	out->Print("method_implementations = {\n");
	for (int i = 0; i < service->method_count(); ++i) {
	IndentScope raii_implementations_indent(out);
	const MethodDescriptor* meth = service->method(i);
	string meth_type =
	string(meth->client_streaming() ? "stream" : "unary") +
	string(meth->server_streaming() ? "_stream" : "_unary") + "_inline";
	// TODO(atash): once the expected input to assemble_dynamic_inline_stub is
	// cleaned up, change this to the expected argument's dictionary values.
	out->Print("\"$Method$\": utilities.$Type$(None),\n",
	"Method", meth->name(),
	"Type", meth_type);
	// Maintain information on the input type of the service method for later
	// use in constructing the service assembly's activated fore link.
	const Descriptor* output_type = meth->output_type();
	pair<string, string> module_and_message;
	if (!GetModuleAndMessagePath(output_type, &module_and_message)) {
	return false;
	}
	method_to_module_and_message.insert(
	make_pair(meth->name(), module_and_message));
	}
	out->Print("}\n");
	// Ensure that we've imported all of the relevant messages.
	for (auto& meth_vals : method_to_module_and_message) {
	out->Print("import $Module$\n",
	"Module", meth_vals.second.first);
	}
	out->Print("response_deserializers = {\n");
	for (auto& meth_vals : method_to_module_and_message) {
	IndentScope raii_serializers_indent(out);
	string full_output_type_path = meth_vals.second.first + "." +
	meth_vals.second.second;
	out->Print("\"$Method$\": $Type$.FromString,\n",
	"Method", meth_vals.first,
	"Type", full_output_type_path);
	}
	out->Print("}\n");
	out->Print("request_serializers = {\n");
	for (auto& meth_vals : method_to_module_and_message) {
	IndentScope raii_serializers_indent(out);
	out->Print("\"$Method$\": lambda x: x.SerializeToString(),\n",
	"Method", meth_vals.first);
	}
	out->Print("}\n");
	out->Print("link = rear.activated_rear_link("
	"host, port, request_serializers, response_deserializers)\n");
	out->Print("return implementations.assemble_dynamic_inline_stub("
	"method_implementations, link)\n");
	}
	return true;
	}

	bool PrintPreamble(const FileDescriptor* file, Printer* out) {
	out->Print("import abc\n");
	out->Print("from grpc._adapter import fore\n");
	out->Print("from grpc._adapter import rear\n");
	out->Print("from grpc.framework.assembly import implementations\n");
	out->Print("from grpc.framework.assembly import utilities\n");
	return true;
	}

	} // namespace

	pair<bool, string> GetServices(const FileDescriptor* file) {
	string output;
	{
	// Scope the output stream so it closes and finalizes output to the string.
	StringOutputStream output_stream(&output);
	Printer out(&output_stream, '$');
	if (!PrintPreamble(file, &out)) {
	return make_pair(false, "");
	}
	for (int i = 0; i < file->service_count(); ++i) {
	auto service = file->service(i);
	if (!(PrintServicer(service, &out) &&
	PrintServer(service, &out) &&
	PrintStub(service, &out) &&
	PrintServerFactory(service, &out) &&
	PrintStubFactory(service, &out))) {
	return make_pair(false, "");
	}
	}
	}
	return make_pair(true, std::move(output));
	}

	} // namespace grpc_python_generator