Support for Golang GRPC (Experimental) (#4082)

* support for grpc golang * refactored grpc go generator * added grpc-go test and refactored * refactored idl_gen_grpc.cpp * fixed grpc generate method name * refactored flatc and fixed line length issue * added codec to go lib and fixed formatting issues * fixed spacing issues
2026-06-11 07:27:27 +00:00 · 2016-12-06 02:50:38 +05:30
parent bc2ec7119b
commit a31ddd2bb3
10 changed files with 819 additions and 11 deletions
--- a/grpc/src/compiler/go_generator.cc
+++ b/grpc/src/compiler/go_generator.cc
@@ -0,0 +1,437 @@
+/*
+ *
+ * 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 AN/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 <map>
+#include <cctype>
+#include <sstream>
+
+#include "src/compiler/go_generator.h"
+
+template <class T>
+grpc::string as_string(T x) {
+	std::ostringstream out;
+	out << x;
+	return out.str();
+}
+
+namespace grpc_go_generator {
+
+// Returns string with first letter to lowerCase
+grpc::string unexportName(grpc::string s) {
+	if (s.size() <= 0)
+		return s;
+	s[0] = std::tolower(s[0]);
+	return s;
+}
+
+// Returns string with first letter to uppercase
+grpc::string exportName(grpc::string s) {
+	if (s.size() <= 0)
+		return s;
+	s[0] = std::toupper(s[0]);
+	return s;
+}
+
+// Generates imports for the service
+void GenerateImports(grpc_generator::File *file, grpc_generator::Printer *printer,
+                     std::map<grpc::string, grpc::string> vars) {
+	vars["filename"] = file->filename();
+	printer->Print("//Generated by gRPC Go plugin\n");
+	printer->Print("//If you make any local changes, they will be lost\n");
+	printer->Print(vars, "//source: $filename$\n\n");
+	printer->Print(vars, "package $Package$\n\n");
+	if (file->additional_imports() != "") {
+		printer->Print(file->additional_imports().c_str());
+		printer->Print("\n\n");
+	}
+	printer->Print("import (\n");
+	printer->Indent();
+	printer->Print(vars, "$context$ \"golang.org/x/net/context\"\n");
+	printer->Print(vars, "$grpc$ \"google.golang.org/grpc\"\n");
+	printer->Outdent();
+	printer->Print(")\n\n");
+}
+
+// Generates Server method signature source
+void GenerateServerMethodSignature(const grpc_generator::Method *method, grpc_generator::Printer *printer,
+                                   std::map<grpc::string, grpc::string> vars) {
+	vars["Method"] = exportName(method->name());
+	vars["Request"] = method->input_name();
+	vars["Response"] = (vars["CustomMethodIO"] == "") ? method->output_name() : vars["CustomMethodIO"];
+	if (method->NoStreaming()) {
+		printer->Print(vars, "$Method$($context$.Context, *$Request$) (*$Response$, error)");
+	} else if (method->ServerOnlyStreaming()) {
+		printer->Print(vars, "$Method$(*$Request$, $Service$_$Method$Server) error");
+	} else {
+		printer->Print(vars, "$Method$($Service$_$Method$Server) error");
+	}
+}
+
+void GenerateServerMethod(const grpc_generator::Method *method, grpc_generator::Printer *printer,
+                          std::map<grpc::string, grpc::string> vars) {
+	vars["Method"] = exportName(method->name());
+	vars["Request"] = method->input_name();
+	vars["Response"] = (vars["CustomMethodIO"] == "") ? method->output_name() : vars["CustomMethodIO"];
+	vars["FullMethodName"] = "/" + vars["Package"] + "." + vars["Service"] + "/" + vars["Method"];
+	vars["Handler"] = "_" + vars["Service"] + "_" + vars["Method"] + "_Handler";
+	if (method->NoStreaming()) {
+		printer->Print(vars, "func $Handler$(srv interface{}, ctx $context$.Context,\n\tdec func(interface{}) error, interceptor $grpc$.UnaryServerInterceptor) (interface{}, error) {\n");
+		printer->Indent();
+		printer->Print(vars, "in := new($Request$)\n");
+		printer->Print("if err := dec(in); err != nil { return nil, err }\n");
+		printer->Print(vars, "if interceptor == nil { return srv.($Service$Server).$Method$(ctx, in) }\n");
+		printer->Print(vars, "info := &$grpc$.UnaryServerInfo{\n");
+		printer->Indent();
+		printer->Print("Server: srv,\n");
+		printer->Print(vars, "FullMethod: \"$FullMethodName$\",\n");
+		printer->Outdent();
+		printer->Print("}\n\n");
+		printer->Print(vars, "handler := func(ctx $context$.Context, req interface{}) (interface{}, error) {\n");
+		printer->Indent();
+		printer->Print(vars, "return srv.($Service$Server).$Method$(ctx, req.(* $Request$))\n");
+		printer->Outdent();
+		printer->Print("}\n");
+		printer->Print("return interceptor(ctx, in, info, handler)\n");
+		printer->Outdent();
+		printer->Print("}\n\n");
+		return;
+	}
+	vars["StreamType"] = vars["ServiceUnexported"] + vars["Method"] + "Server";
+	printer->Print(vars, "func $Handler$(srv interface{}, stream $grpc$.ServerStream) error {\n");
+	printer->Indent();
+	if (method->ServerOnlyStreaming()) {
+		printer->Print(vars, "m := new($Request$)\n");
+		printer->Print(vars, "if err := stream.RecvMsg(m); err != nil { return err }\n");
+		printer->Print(vars, "return srv.($Service$Server).$Method$(m, &$StreamType${stream})\n");
+	} else {
+		printer->Print(vars, "return srv.($Service$Server).$Method$(&$StreamType${stream})\n");
+	}
+	printer->Outdent();
+	printer->Print("}\n\n");
+
+	bool genSend = method->BidiStreaming() || method->ServerOnlyStreaming();
+	bool genRecv = method->BidiStreaming() || method->ClientOnlyStreaming();
+	bool genSendAndClose = method->ClientOnlyStreaming();
+
+	printer->Print(vars, "type $Service$_$Method$Server interface { \n");
+	printer->Indent();
+	if (genSend) {
+		printer->Print(vars, "Send(* $Response$) error\n");
+	}
+	if (genRecv) {
+		printer->Print(vars, "Recv() (* $Request$, error)\n");
+	}
+	if (genSendAndClose) {
+		printer->Print(vars, "SendAndClose(* $Response$) error\n");
+	}
+	printer->Print(vars, "$grpc$.ServerStream\n");
+	printer->Outdent();
+	printer->Print("}\n\n");
+
+	printer->Print(vars, "type $StreamType$ struct {\n");
+	printer->Indent();
+	printer->Print(vars, "$grpc$.ServerStream\n");
+	printer->Outdent();
+	printer->Print("}\n\n");
+
+	if (genSend) {
+		printer->Print(vars, "func (x *$StreamType$) Send(m *$Response$) error {\n");
+		printer->Indent();
+		printer->Print("return x.ServerStream.SendMsg(m)\n");
+		printer->Outdent();
+		printer->Print("}\n\n");
+	}
+	if (genRecv) {
+		printer->Print(vars, "func (x *$StreamType$) Recv() (*$Request$, error) {\n");
+		printer->Indent();
+		printer->Print(vars, "m := new($Request$)\n");
+		printer->Print("if err := x.ServerStream.RecvMsg(m); err != nil { return nil, err }\n");
+		printer->Print("return m, nil\n");
+		printer->Outdent();
+		printer->Print("}\n\n");
+	}
+	if (genSendAndClose) {
+		printer->Print(vars, "func (x *$StreamType$) SendAndClose(m *$Response$) error {\n");
+		printer->Indent();
+		printer->Print("return x.ServerStream.SendMsg(m)\n");
+		printer->Outdent();
+		printer->Print("}\n\n");
+	}
+
+}
+
+// Generates Client method signature source
+void GenerateClientMethodSignature(const grpc_generator::Method *method, grpc_generator::Printer *printer,
+                                   std::map<grpc::string, grpc::string> vars) {
+	vars["Method"] = exportName(method->name());
+	vars["Request"] = ", in *" + ((vars["CustomMethodIO"] == "") ? method->input_name() : vars["CustomMethodIO"]);
+	if (method->ClientOnlyStreaming() || method->BidiStreaming()) {
+		vars["Request"] = "";
+	}
+	vars["Response"] = "* " + method->output_name();
+	if (method->ClientOnlyStreaming() || method->BidiStreaming() || method->ServerOnlyStreaming()) {
+		vars["Response"] = vars["Service"] + "_" + vars["Method"] + "Client" ;
+	}
+	printer->Print(vars, "$Method$(ctx $context$.Context$Request$, \n\topts... $grpc$.CallOption) ($Response$, error)");
+}
+
+// Generates Client method source
+void GenerateClientMethod(const grpc_generator::Method *method, grpc_generator::Printer *printer,
+                          std::map<grpc::string, grpc::string> vars) {
+	printer->Print(vars, "func (c *$ServiceUnexported$Client) ");
+	GenerateClientMethodSignature(method, printer, vars);
+	printer->Print(" {\n");
+	printer->Indent();
+	vars["Method"] = exportName(method->name());
+	vars["Request"] = (vars["CustomMethodIO"] == "") ? method->input_name() : vars["CustomMethodIO"];
+	vars["Response"] = method->output_name();
+	vars["FullMethodName"] = "/" + vars["Package"] + "." + vars["Service"] + "/" + vars["Method"];
+	if (method->NoStreaming()) {
+		printer->Print(vars, "out := new($Response$)\n");
+		printer->Print(vars, "err := $grpc$.Invoke(ctx, \"$FullMethodName$\", in, out, c.cc, opts...)\n");
+		printer->Print("if err != nil { return nil, err }\n");
+		printer->Print("return out, nil\n");
+		printer->Outdent();
+		printer->Print("}\n\n");
+		return;
+	}
+	vars["StreamType"] = vars["ServiceUnexported"] + vars["Method"] + "Client";
+	printer->Print(vars, "stream, err := $grpc$.NewClientStream(ctx, &$MethodDesc$, c.cc, \"$FullMethodName$\", opts...)\n");
+	printer->Print("if err != nil { return nil, err }\n");
+
+	printer->Print(vars, "x := &$StreamType${stream}\n");
+	if (method->ServerOnlyStreaming()) {
+		printer->Print("if err := x.ClientStream.SendMsg(in); err != nil { return nil, err }\n");
+		printer->Print("if err := x.ClientStream.CloseSend(); err != nil { return nil, err }\n");
+	}
+	printer->Print("return x,nil\n");
+	printer->Outdent();
+	printer->Print("}\n\n");
+
+	bool genSend = method->BidiStreaming() || method->ClientOnlyStreaming();
+	bool genRecv = method->BidiStreaming() || method->ServerOnlyStreaming();
+	bool genCloseAndRecv = method->ClientOnlyStreaming();
+
+	//Stream interface
+	printer->Print(vars, "type $Service$_$Method$Client interface {\n");
+	printer->Indent();
+	if (genSend) {
+		printer->Print(vars, "Send(*$Request$) error\n");
+	}
+	if (genRecv) {
+		printer->Print(vars, "Recv() (*$Response$, error)\n");
+	}
+	if (genCloseAndRecv) {
+		printer->Print(vars, "CloseAndRecv() (*$Response$, error)\n");
+	}
+	printer->Print(vars, "$grpc$.ClientStream\n");
+	printer->Outdent();
+	printer->Print("}\n\n");
+
+	//Stream Client
+	printer->Print(vars, "type $StreamType$ struct{\n");
+	printer->Indent();
+	printer->Print(vars, "$grpc$.ClientStream\n");
+	printer->Outdent();
+	printer->Print("}\n\n");
+
+	if (genSend) {
+		printer->Print(vars, "func (x *$StreamType$) Send(m *$Request$) error {\n");
+		printer->Indent();
+		printer->Print("return x.ClientStream.SendMsg(m)\n");
+		printer->Outdent();
+		printer->Print("}\n\n");
+	}
+
+	if (genRecv) {
+		printer->Print(vars, "func (x *$StreamType$) Recv() (*$Response$, error) {\n");
+		printer->Indent();
+		printer->Print(vars, "m := new($Response$)\n");
+		printer->Print("if err := x.ClientStream.RecvMsg(m); err != nil { return nil, err }\n");
+		printer->Print("return m, nil\n");
+		printer->Outdent();
+		printer->Print("}\n\n");
+	}
+
+	if (genCloseAndRecv) {
+		printer->Print(vars, "func (x *$StreamType$) CloseAndRecv() (*$Response$, error) {\n");
+		printer->Indent();
+		printer->Print("if err := x.ClientStream.CloseSend(); err != nil { return nil, err }\n");
+		printer->Print(vars, "m := new ($Response$)\n");
+		printer->Print("if err := x.ClientStream.RecvMsg(m); err != nil { return nil, err }\n");
+		printer->Print("return m, nil\n");
+		printer->Outdent();
+		printer->Print("}\n\n");
+	}
+}
+
+// Generates client API for the service
+void GenerateService(const grpc_generator::Service *service, grpc_generator::Printer* printer,
+                     std::map<grpc::string, grpc::string> vars) {
+	vars["Service"] = exportName(service->name());
+	// Client Interface
+	printer->Print(vars, "// Client API for $Service$ service\n");
+	printer->Print(vars, "type $Service$Client interface{\n");
+	printer->Indent();
+	for (int i = 0; i < service->method_count(); i++) {
+		GenerateClientMethodSignature(service->method(i).get(), printer, vars);
+		printer->Print("\n");
+	}
+	printer->Outdent();
+	printer->Print("}\n\n");
+
+	// Client structure
+	vars["ServiceUnexported"] = unexportName(vars["Service"]);
+	printer->Print(vars, "type $ServiceUnexported$Client struct {\n");
+	printer->Indent();
+	printer->Print(vars, "cc *$grpc$.ClientConn\n");
+	printer->Outdent();
+	printer->Print("}\n\n");
+
+	// NewClient
+	printer->Print(vars, "func New$Service$Client(cc *$grpc$.ClientConn) $Service$Client {\n");
+	printer->Indent();
+	printer->Print(vars, "return &$ServiceUnexported$Client{cc}");
+	printer->Outdent();
+	printer->Print("\n}\n\n");
+
+	int unary_methods = 0, streaming_methods = 0;
+	vars["ServiceDesc"] = "_" + vars["Service"] + "_serviceDesc";
+	for (int i = 0; i < service->method_count(); i++) {
+		auto method = service->method(i);
+		if (method->NoStreaming()) {
+			vars["MethodDesc"] = vars["ServiceDesc"] + ".Method[" + as_string(unary_methods) + "]";
+			unary_methods++;
+		} else {
+			vars["MethodDesc"] = vars["ServiceDesc"] + ".Streams[" + as_string(streaming_methods) + "]";
+			streaming_methods++;
+		}
+		GenerateClientMethod(method.get(), printer, vars);
+	}
+
+	//Server Interface
+	printer->Print(vars, "// Server API for $Service$ service\n");
+	printer->Print(vars, "type $Service$Server interface {\n");
+	printer->Indent();
+	for (int i = 0; i < service->method_count(); i++) {
+		GenerateServerMethodSignature(service->method(i).get(), printer, vars);
+		printer->Print("\n");
+	}
+	printer->Outdent();
+	printer->Print("}\n\n");
+
+	// Server registration.
+	printer->Print(vars, "func Register$Service$Server(s *$grpc$.Server, srv $Service$Server) {\n");
+	printer->Indent();
+	printer->Print(vars, "s.RegisterService(&$ServiceDesc$, srv)\n");
+	printer->Outdent();
+	printer->Print("}\n\n");
+
+	for (int i = 0; i < service->method_count(); i++) {
+		GenerateServerMethod(service->method(i).get(), printer, vars);
+		printer->Print("\n");
+	}
+
+
+	//Service Descriptor
+	printer->Print(vars, "var $ServiceDesc$ = $grpc$.ServiceDesc{\n");
+	printer->Indent();
+	printer->Print(vars, "ServiceName: \"$Package$.$Service$\",\n");
+	printer->Print(vars, "HandlerType: (*$Service$Server)(nil),\n");
+	printer->Print(vars, "Methods: []$grpc$.MethodDesc{\n");
+	printer->Indent();
+	for (int i = 0; i < service->method_count(); i++) {
+		auto method = service->method(i);
+		vars["Method"] = method->name();
+		vars["Handler"] = "_" + vars["Service"] + "_" + vars["Method"] + "_Handler";
+		if (method->NoStreaming()) {
+			printer->Print("{\n");
+			printer->Indent();
+			printer->Print(vars, "MethodName: \"$Method$\",\n");
+			printer->Print(vars, "Handler: $Handler$, \n");
+			printer->Outdent();
+			printer->Print("},\n");
+		}
+	}
+	printer->Outdent();
+	printer->Print("},\n");
+	printer->Print(vars, "Streams: []$grpc$.StreamDesc{\n");
+	printer->Indent();
+	for (int i = 0; i < service->method_count(); i++) {
+		auto method = service->method(i);
+		vars["Method"] = method->name();
+		vars["Handler"] = "_" + vars["Service"] + "_" + vars["Method"] + "_Handler";
+		if (!method->NoStreaming()) {
+			printer->Print("{\n");
+			printer->Indent();
+			printer->Print(vars, "StreamName: \"$Method$\",\n");
+			printer->Print(vars, "Handler: $Handler$, \n");
+			if (method->ClientOnlyStreaming()) {
+				printer->Print("ClientStreams: true,\n");
+			} else if (method->ServerOnlyStreaming()) {
+				printer->Print("ServerStreams: true,\n");
+			} else {
+				printer->Print("ServerStreams: true,\n");
+				printer->Print("ClientStreams: true,\n");
+			}
+			printer->Outdent();
+			printer->Print("},\n");
+		}
+	}
+	printer->Outdent();
+	printer->Print("},\n");
+	printer->Outdent();
+	printer->Print("}\n\n");
+
+}
+
+
+// Returns source for the service
+grpc::string GenerateServiceSource(grpc_generator::File *file,
+                                   const grpc_generator::Service *service,
+                                   grpc_go_generator::Parameters *parameters) {
+	grpc::string out;
+	auto p = file->CreatePrinter(&out);
+	auto printer = p.get();
+	std::map<grpc::string, grpc::string> vars;
+	vars["Package"] = parameters->package_name;
+	vars["grpc"] = "grpc";
+	vars["context"] = "context";
+	GenerateImports(file, printer, vars);
+	if (parameters->custom_method_io_type != "") {
+		vars["CustomMethodIO"] = parameters->custom_method_io_type;
+	}
+	GenerateService(service, printer, vars);
+	return out;
+}
+}// Namespace grpc_go_generator
--- a/grpc/src/compiler/go_generator.h
+++ b/grpc/src/compiler/go_generator.h
@@ -0,0 +1,61 @@
+/*
+ *
+ * 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_GO_GENERATOR_H
+#define GRPC_INTERNAL_COMPILER_GO_GENERATOR_H
+
+//go generator is used to generate GRPC code for serialization system, such as flatbuffers
+#include <memory>
+#include <vector>
+
+#include "src/compiler/schema_interface.h"
+
+namespace grpc_go_generator {
+
+struct Parameters {
+	//Defines the custom parameter types for methods
+	//eg: flatbuffers uses flatbuffers.Builder as input for the client and output for the server
+	grpc::string custom_method_io_type;
+
+	//Package name for the service
+	grpc::string package_name;
+};
+
+// Return the source of the generated service file.
+grpc::string GenerateServiceSource(grpc_generator::File *file,
+                                   const grpc_generator::Service *service,
+                                   grpc_go_generator::Parameters *parameters);
+
+}
+
+#endif  // GRPC_INTERNAL_COMPILER_GO_GENERATOR_H
--- a/grpc/src/compiler/schema_interface.h
+++ b/grpc/src/compiler/schema_interface.h
@@ -59,6 +59,8 @@ namespace grpc_generator {

    virtual grpc::string input_type_name() const = 0;
    virtual grpc::string output_type_name() const = 0;
+    virtual grpc::string input_name() const = 0;
+    virtual grpc::string output_name() const = 0;

    virtual bool NoStreaming() const = 0;
    virtual bool ClientOnlyStreaming() const = 0;
@@ -98,6 +100,7 @@ namespace grpc_generator {
    virtual grpc::string package() const = 0;
    virtual std::vector<grpc::string> package_parts() const = 0;
    virtual grpc::string additional_headers() const = 0;
+    virtual grpc::string additional_imports() const = 0;

    virtual int service_count() const = 0;
    virtual std::unique_ptr<const Service> service(int i) const = 0;