464 lines
15 KiB
Go
464 lines
15 KiB
Go
// Go support for Protocol Buffers - Google's data interchange format
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//
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// Copyright 2015 The Go Authors. All rights reserved.
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// https://github.com/golang/protobuf
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//
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are
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// met:
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//
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// * Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above
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// copyright notice, this list of conditions and the following disclaimer
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// in the documentation and/or other materials provided with the
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// distribution.
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// * Neither the name of Google Inc. nor the names of its
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// contributors may be used to endorse or promote products derived from
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// this software without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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// Package grpc outputs gRPC service descriptions in Go code.
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// It runs as a plugin for the Go protocol buffer compiler plugin.
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// It is linked in to protoc-gen-go.
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package grpc
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import (
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"fmt"
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"path"
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"strconv"
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"strings"
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pb "github.com/golang/protobuf/protoc-gen-go/descriptor"
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"github.com/golang/protobuf/protoc-gen-go/generator"
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)
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// generatedCodeVersion indicates a version of the generated code.
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// It is incremented whenever an incompatibility between the generated code and
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// the grpc package is introduced; the generated code references
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// a constant, grpc.SupportPackageIsVersionN (where N is generatedCodeVersion).
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const generatedCodeVersion = 3
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// Paths for packages used by code generated in this file,
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// relative to the import_prefix of the generator.Generator.
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const (
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contextPkgPath = "golang.org/x/net/context"
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grpcPkgPath = "google.golang.org/grpc"
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)
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func init() {
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generator.RegisterPlugin(new(grpc))
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}
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// grpc is an implementation of the Go protocol buffer compiler's
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// plugin architecture. It generates bindings for gRPC support.
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type grpc struct {
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gen *generator.Generator
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}
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// Name returns the name of this plugin, "grpc".
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func (g *grpc) Name() string {
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return "grpc"
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}
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// The names for packages imported in the generated code.
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// They may vary from the final path component of the import path
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// if the name is used by other packages.
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var (
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contextPkg string
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grpcPkg string
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)
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// Init initializes the plugin.
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func (g *grpc) Init(gen *generator.Generator) {
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g.gen = gen
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contextPkg = generator.RegisterUniquePackageName("context", nil)
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grpcPkg = generator.RegisterUniquePackageName("grpc", nil)
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}
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// Given a type name defined in a .proto, return its object.
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// Also record that we're using it, to guarantee the associated import.
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func (g *grpc) objectNamed(name string) generator.Object {
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g.gen.RecordTypeUse(name)
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return g.gen.ObjectNamed(name)
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}
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// Given a type name defined in a .proto, return its name as we will print it.
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func (g *grpc) typeName(str string) string {
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return g.gen.TypeName(g.objectNamed(str))
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}
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// P forwards to g.gen.P.
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func (g *grpc) P(args ...interface{}) { g.gen.P(args...) }
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// Generate generates code for the services in the given file.
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func (g *grpc) Generate(file *generator.FileDescriptor) {
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if len(file.FileDescriptorProto.Service) == 0 {
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return
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}
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g.P("// Reference imports to suppress errors if they are not otherwise used.")
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g.P("var _ ", contextPkg, ".Context")
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g.P("var _ ", grpcPkg, ".ClientConn")
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g.P()
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// Assert version compatibility.
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g.P("// This is a compile-time assertion to ensure that this generated file")
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g.P("// is compatible with the grpc package it is being compiled against.")
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g.P("const _ = ", grpcPkg, ".SupportPackageIsVersion", generatedCodeVersion)
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g.P()
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for i, service := range file.FileDescriptorProto.Service {
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g.generateService(file, service, i)
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}
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}
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// GenerateImports generates the import declaration for this file.
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func (g *grpc) GenerateImports(file *generator.FileDescriptor) {
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if len(file.FileDescriptorProto.Service) == 0 {
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return
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}
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g.P("import (")
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g.P(contextPkg, " ", strconv.Quote(path.Join(g.gen.ImportPrefix, contextPkgPath)))
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g.P(grpcPkg, " ", strconv.Quote(path.Join(g.gen.ImportPrefix, grpcPkgPath)))
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g.P(")")
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g.P()
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}
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// reservedClientName records whether a client name is reserved on the client side.
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var reservedClientName = map[string]bool{
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// TODO: do we need any in gRPC?
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}
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func unexport(s string) string { return strings.ToLower(s[:1]) + s[1:] }
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// generateService generates all the code for the named service.
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func (g *grpc) generateService(file *generator.FileDescriptor, service *pb.ServiceDescriptorProto, index int) {
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path := fmt.Sprintf("6,%d", index) // 6 means service.
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origServName := service.GetName()
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fullServName := origServName
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if pkg := file.GetPackage(); pkg != "" {
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fullServName = pkg + "." + fullServName
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}
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servName := generator.CamelCase(origServName)
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g.P()
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g.P("// Client API for ", servName, " service")
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g.P()
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// Client interface.
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g.P("type ", servName, "Client interface {")
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for i, method := range service.Method {
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g.gen.PrintComments(fmt.Sprintf("%s,2,%d", path, i)) // 2 means method in a service.
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g.P(g.generateClientSignature(servName, method))
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}
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g.P("}")
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g.P()
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// Client structure.
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g.P("type ", unexport(servName), "Client struct {")
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g.P("cc *", grpcPkg, ".ClientConn")
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g.P("}")
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g.P()
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// NewClient factory.
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g.P("func New", servName, "Client (cc *", grpcPkg, ".ClientConn) ", servName, "Client {")
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g.P("return &", unexport(servName), "Client{cc}")
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g.P("}")
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g.P()
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var methodIndex, streamIndex int
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serviceDescVar := "_" + servName + "_serviceDesc"
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// Client method implementations.
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for _, method := range service.Method {
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var descExpr string
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if !method.GetServerStreaming() && !method.GetClientStreaming() {
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// Unary RPC method
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descExpr = fmt.Sprintf("&%s.Methods[%d]", serviceDescVar, methodIndex)
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methodIndex++
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} else {
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// Streaming RPC method
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descExpr = fmt.Sprintf("&%s.Streams[%d]", serviceDescVar, streamIndex)
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streamIndex++
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}
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g.generateClientMethod(servName, fullServName, serviceDescVar, method, descExpr)
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}
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g.P("// Server API for ", servName, " service")
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g.P()
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// Server interface.
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serverType := servName + "Server"
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g.P("type ", serverType, " interface {")
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for i, method := range service.Method {
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g.gen.PrintComments(fmt.Sprintf("%s,2,%d", path, i)) // 2 means method in a service.
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g.P(g.generateServerSignature(servName, method))
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}
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g.P("}")
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g.P()
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// Server registration.
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g.P("func Register", servName, "Server(s *", grpcPkg, ".Server, srv ", serverType, ") {")
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g.P("s.RegisterService(&", serviceDescVar, `, srv)`)
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g.P("}")
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g.P()
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// Server handler implementations.
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var handlerNames []string
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for _, method := range service.Method {
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hname := g.generateServerMethod(servName, fullServName, method)
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handlerNames = append(handlerNames, hname)
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}
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// Service descriptor.
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g.P("var ", serviceDescVar, " = ", grpcPkg, ".ServiceDesc {")
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g.P("ServiceName: ", strconv.Quote(fullServName), ",")
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g.P("HandlerType: (*", serverType, ")(nil),")
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g.P("Methods: []", grpcPkg, ".MethodDesc{")
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for i, method := range service.Method {
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if method.GetServerStreaming() || method.GetClientStreaming() {
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continue
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}
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g.P("{")
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g.P("MethodName: ", strconv.Quote(method.GetName()), ",")
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g.P("Handler: ", handlerNames[i], ",")
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g.P("},")
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}
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g.P("},")
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g.P("Streams: []", grpcPkg, ".StreamDesc{")
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for i, method := range service.Method {
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if !method.GetServerStreaming() && !method.GetClientStreaming() {
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continue
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}
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g.P("{")
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g.P("StreamName: ", strconv.Quote(method.GetName()), ",")
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g.P("Handler: ", handlerNames[i], ",")
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if method.GetServerStreaming() {
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g.P("ServerStreams: true,")
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}
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if method.GetClientStreaming() {
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g.P("ClientStreams: true,")
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}
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g.P("},")
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}
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g.P("},")
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g.P("Metadata: ", file.VarName(), ",")
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g.P("}")
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g.P()
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}
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// generateClientSignature returns the client-side signature for a method.
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func (g *grpc) generateClientSignature(servName string, method *pb.MethodDescriptorProto) string {
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origMethName := method.GetName()
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methName := generator.CamelCase(origMethName)
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if reservedClientName[methName] {
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methName += "_"
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}
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reqArg := ", in *" + g.typeName(method.GetInputType())
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if method.GetClientStreaming() {
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reqArg = ""
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}
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respName := "*" + g.typeName(method.GetOutputType())
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if method.GetServerStreaming() || method.GetClientStreaming() {
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respName = servName + "_" + generator.CamelCase(origMethName) + "Client"
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}
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return fmt.Sprintf("%s(ctx %s.Context%s, opts ...%s.CallOption) (%s, error)", methName, contextPkg, reqArg, grpcPkg, respName)
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}
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func (g *grpc) generateClientMethod(servName, fullServName, serviceDescVar string, method *pb.MethodDescriptorProto, descExpr string) {
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sname := fmt.Sprintf("/%s/%s", fullServName, method.GetName())
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methName := generator.CamelCase(method.GetName())
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inType := g.typeName(method.GetInputType())
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outType := g.typeName(method.GetOutputType())
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g.P("func (c *", unexport(servName), "Client) ", g.generateClientSignature(servName, method), "{")
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if !method.GetServerStreaming() && !method.GetClientStreaming() {
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g.P("out := new(", outType, ")")
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// TODO: Pass descExpr to Invoke.
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g.P("err := ", grpcPkg, `.Invoke(ctx, "`, sname, `", in, out, c.cc, opts...)`)
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g.P("if err != nil { return nil, err }")
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g.P("return out, nil")
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g.P("}")
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g.P()
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return
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}
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streamType := unexport(servName) + methName + "Client"
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g.P("stream, err := ", grpcPkg, ".NewClientStream(ctx, ", descExpr, `, c.cc, "`, sname, `", opts...)`)
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g.P("if err != nil { return nil, err }")
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g.P("x := &", streamType, "{stream}")
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if !method.GetClientStreaming() {
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g.P("if err := x.ClientStream.SendMsg(in); err != nil { return nil, err }")
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g.P("if err := x.ClientStream.CloseSend(); err != nil { return nil, err }")
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}
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g.P("return x, nil")
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g.P("}")
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g.P()
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genSend := method.GetClientStreaming()
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genRecv := method.GetServerStreaming()
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genCloseAndRecv := !method.GetServerStreaming()
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// Stream auxiliary types and methods.
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g.P("type ", servName, "_", methName, "Client interface {")
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if genSend {
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g.P("Send(*", inType, ") error")
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}
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if genRecv {
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g.P("Recv() (*", outType, ", error)")
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}
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if genCloseAndRecv {
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g.P("CloseAndRecv() (*", outType, ", error)")
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}
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g.P(grpcPkg, ".ClientStream")
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g.P("}")
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g.P()
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g.P("type ", streamType, " struct {")
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g.P(grpcPkg, ".ClientStream")
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g.P("}")
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g.P()
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if genSend {
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g.P("func (x *", streamType, ") Send(m *", inType, ") error {")
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g.P("return x.ClientStream.SendMsg(m)")
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g.P("}")
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g.P()
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}
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if genRecv {
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g.P("func (x *", streamType, ") Recv() (*", outType, ", error) {")
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g.P("m := new(", outType, ")")
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g.P("if err := x.ClientStream.RecvMsg(m); err != nil { return nil, err }")
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g.P("return m, nil")
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g.P("}")
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g.P()
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}
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if genCloseAndRecv {
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g.P("func (x *", streamType, ") CloseAndRecv() (*", outType, ", error) {")
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g.P("if err := x.ClientStream.CloseSend(); err != nil { return nil, err }")
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g.P("m := new(", outType, ")")
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g.P("if err := x.ClientStream.RecvMsg(m); err != nil { return nil, err }")
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g.P("return m, nil")
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g.P("}")
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g.P()
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}
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}
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// generateServerSignature returns the server-side signature for a method.
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func (g *grpc) generateServerSignature(servName string, method *pb.MethodDescriptorProto) string {
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origMethName := method.GetName()
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methName := generator.CamelCase(origMethName)
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if reservedClientName[methName] {
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methName += "_"
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}
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var reqArgs []string
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ret := "error"
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if !method.GetServerStreaming() && !method.GetClientStreaming() {
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reqArgs = append(reqArgs, contextPkg+".Context")
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ret = "(*" + g.typeName(method.GetOutputType()) + ", error)"
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}
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if !method.GetClientStreaming() {
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reqArgs = append(reqArgs, "*"+g.typeName(method.GetInputType()))
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}
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if method.GetServerStreaming() || method.GetClientStreaming() {
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reqArgs = append(reqArgs, servName+"_"+generator.CamelCase(origMethName)+"Server")
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}
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return methName + "(" + strings.Join(reqArgs, ", ") + ") " + ret
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}
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func (g *grpc) generateServerMethod(servName, fullServName string, method *pb.MethodDescriptorProto) string {
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methName := generator.CamelCase(method.GetName())
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hname := fmt.Sprintf("_%s_%s_Handler", servName, methName)
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inType := g.typeName(method.GetInputType())
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outType := g.typeName(method.GetOutputType())
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if !method.GetServerStreaming() && !method.GetClientStreaming() {
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g.P("func ", hname, "(srv interface{}, ctx ", contextPkg, ".Context, dec func(interface{}) error, interceptor ", grpcPkg, ".UnaryServerInterceptor) (interface{}, error) {")
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g.P("in := new(", inType, ")")
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g.P("if err := dec(in); err != nil { return nil, err }")
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g.P("if interceptor == nil { return srv.(", servName, "Server).", methName, "(ctx, in) }")
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g.P("info := &", grpcPkg, ".UnaryServerInfo{")
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g.P("Server: srv,")
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g.P("FullMethod: ", strconv.Quote(fmt.Sprintf("/%s/%s", fullServName, methName)), ",")
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g.P("}")
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g.P("handler := func(ctx ", contextPkg, ".Context, req interface{}) (interface{}, error) {")
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g.P("return srv.(", servName, "Server).", methName, "(ctx, req.(*", inType, "))")
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g.P("}")
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g.P("return interceptor(ctx, in, info, handler)")
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g.P("}")
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g.P()
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return hname
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}
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streamType := unexport(servName) + methName + "Server"
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g.P("func ", hname, "(srv interface{}, stream ", grpcPkg, ".ServerStream) error {")
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if !method.GetClientStreaming() {
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g.P("m := new(", inType, ")")
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g.P("if err := stream.RecvMsg(m); err != nil { return err }")
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g.P("return srv.(", servName, "Server).", methName, "(m, &", streamType, "{stream})")
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} else {
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g.P("return srv.(", servName, "Server).", methName, "(&", streamType, "{stream})")
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}
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g.P("}")
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g.P()
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genSend := method.GetServerStreaming()
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genSendAndClose := !method.GetServerStreaming()
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genRecv := method.GetClientStreaming()
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// Stream auxiliary types and methods.
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g.P("type ", servName, "_", methName, "Server interface {")
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if genSend {
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g.P("Send(*", outType, ") error")
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}
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if genSendAndClose {
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g.P("SendAndClose(*", outType, ") error")
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}
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if genRecv {
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g.P("Recv() (*", inType, ", error)")
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}
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g.P(grpcPkg, ".ServerStream")
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g.P("}")
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g.P()
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g.P("type ", streamType, " struct {")
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g.P(grpcPkg, ".ServerStream")
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g.P("}")
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g.P()
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if genSend {
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g.P("func (x *", streamType, ") Send(m *", outType, ") error {")
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g.P("return x.ServerStream.SendMsg(m)")
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g.P("}")
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g.P()
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}
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if genSendAndClose {
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g.P("func (x *", streamType, ") SendAndClose(m *", outType, ") error {")
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g.P("return x.ServerStream.SendMsg(m)")
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g.P("}")
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g.P()
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}
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if genRecv {
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g.P("func (x *", streamType, ") Recv() (*", inType, ", error) {")
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g.P("m := new(", inType, ")")
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g.P("if err := x.ServerStream.RecvMsg(m); err != nil { return nil, err }")
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g.P("return m, nil")
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g.P("}")
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g.P()
|
|
}
|
|
|
|
return hname
|
|
}
|