From f577312bf2c1dce2c51ac05e77f1c00024b08243 Mon Sep 17 00:00:00 2001 From: chai2010 Date: Sat, 30 Jun 2018 21:04:19 +0800 Subject: [PATCH] =?UTF-8?q?ch4-02:=20=E5=9F=BA=E4=BA=8E=E6=A8=A1=E6=9D=BF?= =?UTF-8?q?=E7=AE=80=E5=8C=96=E6=8F=92=E4=BB=B6?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- ch4-rpc/ch4-02-pb-intro.md | 239 +++++++----------- examples/ch4-02-proto/proto-v1/hello.pb.go | 4 +- .../protoc-gen-go-netrpc/netprpc.go | 129 ++-------- .../ch4-02-proto/protoc-gen-go-netrpc/spec.go | 37 +++ 4 files changed, 163 insertions(+), 246 deletions(-) create mode 100644 examples/ch4-02-proto/protoc-gen-go-netrpc/spec.go diff --git a/ch4-rpc/ch4-02-pb-intro.md b/ch4-rpc/ch4-02-pb-intro.md index 6878595..5833fd8 100644 --- a/ch4-rpc/ch4-02-pb-intro.md +++ b/ch4-rpc/ch4-02-pb-intro.md @@ -64,13 +64,13 @@ func (m *String) GetValue() string { ```go type HelloService struct{} -func (p *HelloService) Hello(request String, reply *String) error { +func (p *HelloService) Hello(request *String, reply *String) error { reply.Value = "hello:" + request.GetValue() return nil } ``` -其中Hello方法的输入参数和返回的参数均该用Protobuf定义的String类型表示，函数的内部代码同时也做了相应的调整。 +其中Hello方法的输入参数和返回的参数均该用Protobuf定义的String类型表示。因为新的输入参数为结构体类型，因此该用指针类型作为输入参数，函数的内部代码同时也做了相应的调整。 至此，我们初步实现了Protobuf和RPC组合工作。在启动RPC服务时，我们依然可以选择默认的gob或手工指定json编码，甚至可以重新基于protobuf编码实现一个插件。虽然做了这么多工作，但是似乎并没有看到什么收益！ @@ -237,7 +237,7 @@ $ protoc --go-netrpc_out=plugins=netrpc:. hello.proto 在前面的例子中我们已经构件了最小化的netrpcPlugin插件，并且通过克隆protoc-gen-go的主程序创建了新的protoc-gen-go-netrpc的插件程序。我们现在开始继续完善netrpcPlugin插件，最终目标是生成RPC安全接口。 -以下是完善后的GenerateImports和Generate方法： +首先是GenerateImports方法中生成导入包的代码： ```go func (p *netrpcPlugin) GenerateImports(file *generator.FileDescriptor) { @@ -245,153 +245,65 @@ func (p *netrpcPlugin) GenerateImports(file *generator.FileDescriptor) { p.P(`import "net/rpc"`) } } +``` +然后要在Generate中为每个服务生成相关的代码。分析可以发现每个服务最重要的是服务的名字，然后每个服务有一组方法。而对于服务定义的方法，最重要的是方法的名字，还有输入参数和输出参数类型的名字。为此我们定义了一个ServiceSpec类型，用于描述服务的元信息： + +```go +type ServiceSpec struct { + ServiceName string + MethodList []ServiceMethodSpec +} + +type ServiceMethodSpec struct { + MethodName string + InputTypeName string + OutputTypeName string +} +``` + +然后我们新建一个buildServiceSpec方法用来构造每个服务的ServiceSpec元信息： + +```go +func (p *generator.Generator) buildServiceSpec(svc *descriptor.ServiceDescriptorProto) *ServiceSpec { + spec := &ServiceSpec{ + ServiceName: generator.CamelCase(svc.GetName()), + } + + for _, m := range svc.Method { + spec.MethodList = append(spec.MethodList, ServiceMethodSpec{ + MethodName: generator.CamelCase(m.GetName()), + InputTypeName: p.TypeName(p.ObjectNamed(m.GetInputType())), + OutputTypeName: p.TypeName(p.ObjectNamed(m.GetOutputType())), + }) + } + + return spec +} +``` + +然后我们就可以基于buildServiceSpec方法构造的服务的元信息生成服务的代码： + +```go func (p *netrpcPlugin) Generate(file *generator.FileDescriptor) { for _, svc := range file.Service { - p.genServiceInterface(file, svc) - p.genServiceServer(file, svc) - p.genServiceClient(file, svc) + spec := p.buildServiceSpec(svc) + + var buf bytes.Buffer + t := template.Must(template.New("").Parse(tmplService)) + err := t.Execute(&buf, spec) + if err != nil { + log.Fatal(err) + } + + p.P(buf.String()) } } ``` -在导入部分我们增加了导入net/rpc包的语句。而在每个服务部分则通过genServiceInterface方法生成服务的接口，通过genServiceServer方法生成服务的注册函数，通过genServiceClient方法生成客户端包装代码。 +为了便于维护，我们基于Go语言的模板来生成服务代码，其中tmplService是服务的模板。 -首先看看genServiceInterface如何生成服务器接口： - -```go -func (p *netrpcPlugin) genServiceInterface( - file *generator.FileDescriptor, - svc *descriptor.ServiceDescriptorProto, -) { - const serviceInterfaceTmpl = ` -type {{.ServiceName}}Interface interface { - {{.CallMethodList}} -} -` - const callMethodTmpl = ` -{{.MethodName}}(in {{.ArgsType}}, out *{{.ReplyType}}) error` - - // gen call method list - var callMethodList string - for _, m := range svc.Method { - out := bytes.NewBuffer([]byte{}) - t := template.Must(template.New("").Parse(callMethodTmpl)) - t.Execute(out, &struct{ ServiceName, MethodName, ArgsType, ReplyType string }{ - ServiceName: generator.CamelCase(svc.GetName()), - MethodName: generator.CamelCase(m.GetName()), - ArgsType: p.TypeName(p.ObjectNamed(m.GetInputType())), - ReplyType: p.TypeName(p.ObjectNamed(m.GetOutputType())), - }) - callMethodList += out.String() - - p.RecordTypeUse(m.GetInputType()) - p.RecordTypeUse(m.GetOutputType()) - } - - // gen all interface code - out := bytes.NewBuffer([]byte{}) - t := template.Must(template.New("").Parse(serviceInterfaceTmpl)) - t.Execute(out, &struct{ ServiceName, CallMethodList string }{ - ServiceName: generator.CamelCase(svc.GetName()), - CallMethodList: callMethodList, - }) - p.P(out.String()) -} -``` - -生成服务接口时首先需要服务的名字，可以通过`svc.GetName()`获取服务在Proto文件中的名字，然后通过generator.CamelCase函数转为Go语言中修饰后的名字。 - -服务中svc.Method是一个表示方法信息的切片。要生成每个方法，需要知道每个方法的名字、输入参数类型、输出参数类型。其中m.GetName()是获取原始的方法名字，同样需要通过generator.CamelCase转化为Go语言中修饰后的名字。而`p.TypeName(p.ObjectNamed(m.GetInputType()))`和`p.TypeName(p.ObjectNamed(m.GetOutputType()))`分别用户获取输入参数和输出参数的类型名字。 - -然后是生成RPC注册方法的genServiceServer函数： - -```go -func (p *netrpcPlugin) genServiceServer( - file *generator.FileDescriptor, - svc *descriptor.ServiceDescriptorProto, -) { - const serviceHelperFunTmpl = ` -func Register{{.ServiceName}}(srv *rpc.Server, x {{.ServiceName}}) error { - if err := srv.RegisterName("{{.ServiceName}}", x); err != nil { - return err - } - return nil -} -` - out := bytes.NewBuffer([]byte{}) - t := template.Must(template.New("").Parse(serviceHelperFunTmpl)) - t.Execute(out, &struct{ PackageName, ServiceName, ServiceRegisterName string }{ - PackageName: file.GetPackage(), - ServiceName: generator.CamelCase(svc.GetName()), - }) - p.P(out.String()) -} -``` - -genServiceServer函数的实现和生成接口的代码类似，依然是才有Go语言的模板生成目标代码。 - -最后是genServiceClient函数生成客户端包装代码： - -```go - -func (p *netrpcPlugin) genServiceClient( - file *generator.FileDescriptor, - svc *descriptor.ServiceDescriptorProto, -) { - const clientHelperFuncTmpl = ` -type {{.ServiceName}}Client struct { - *rpc.Client -} - -var _ {{.ServiceName}}Interface = (*{{.ServiceName}}Client)(nil) - -func Dial{{.ServiceName}}(network, address string) (*{{.ServiceName}}Client, error) { - c, err := rpc.Dial(network, address) - if err != nil { - return nil, err - } - return &{{.ServiceName}}Client{Client: c}, nil -} - -{{.MethodList}} -` - const clientMethodTmpl = ` -func (p *{{.ServiceName}}Client) {{.MethodName}}(in {{.ArgsType}}, out *{{.ReplyType}}) error { - return p.Client.Call("{{.ServiceName}}.{{.MethodName}}", in, out) -} -` - - // gen client method list - var methodList string - for _, m := range svc.Method { - out := bytes.NewBuffer([]byte{}) - t := template.Must(template.New("").Parse(clientMethodTmpl)) - t.Execute(out, &struct{ ServiceName, ServiceRegisterName, MethodName, ArgsType, ReplyType string }{ - ServiceName: generator.CamelCase(svc.GetName()), - ServiceRegisterName: file.GetPackage() + "." + generator.CamelCase(svc.GetName()), - MethodName: generator.CamelCase(m.GetName()), - ArgsType: p.TypeName(p.ObjectNamed(m.GetInputType())), - ReplyType: p.TypeName(p.ObjectNamed(m.GetOutputType())), - }) - methodList += out.String() - } - - // gen all client code - out := bytes.NewBuffer([]byte{}) - t := template.Must(template.New("").Parse(clientHelperFuncTmpl)) - t.Execute(out, &struct{ PackageName, ServiceName, MethodList string }{ - PackageName: file.GetPackage(), - ServiceName: generator.CamelCase(svc.GetName()), - MethodList: methodList, - }) - p.P(out.String()) -} -``` - -除了模板不同，客户端的生成代码逻辑服务接口的生成函数也是类似的。 - -最后我们可以查看下netrpcPlugin插件生成的RPC代码： +在编写模板之前，我们先查看下我们期望生成的最终代码大概是什么样子： ```go type HelloServiceInterface interface { @@ -424,6 +336,49 @@ func (p *HelloServiceClient) Hello(in String, out *String) error { } ``` +其中HelloService是服务名字，同时还有一系列的方法相关的名字。 + +参考最终要生成的代码可以构建如下模板： + +```go +const tmplService = ` +{{$root := .}} + +type {{.ServiceName}}Interface interface { + {{- range $_, $m := .MethodList}} + {{$m.MethodName}}(in *{{$m.InputTypeName}}, out *{{$m.OutputTypeName}}) error + {{- end}} +} + +func Register{{.ServiceName}}(srv *rpc.Server, x {{.ServiceName}}) error { + if err := srv.RegisterName("{{.ServiceName}}", x); err != nil { + return err + } + return nil +} + +type {{.ServiceName}}Client struct { + *rpc.Client +} + +var _ {{.ServiceName}}Interface = (*{{.ServiceName}}Client)(nil) + +func Dial{{.ServiceName}}(network, address string) (*{{.ServiceName}}Client, error) { + c, err := rpc.Dial(network, address) + if err != nil { + return nil, err + } + return &{{.ServiceName}}Client{Client: c}, nil +} + +{{range $_, $m := .MethodList}} +func (p *{{$root.ServiceName}}Client) {{$m.MethodName}}(in *{{$m.InputTypeName}}, out *{{$m.OutputTypeName}}) error { + return p.Client.Call("{{$root.ServiceName}}.{{$m.MethodName}}", in, out) +} +{{end}} +` +``` + 当Protobuf的插件定制工作完成后，每次hello.proto文件中RPC服务的变化都可以自动生成代码。同时，才有类似的技术也可以为其它语言编写代码生成插件。 在掌握了定制Protobuf插件技术后，你将彻底拥有这个技术。 diff --git a/examples/ch4-02-proto/proto-v1/hello.pb.go b/examples/ch4-02-proto/proto-v1/hello.pb.go index 67a77ae..73d46ea 100644 --- a/examples/ch4-02-proto/proto-v1/hello.pb.go +++ b/examples/ch4-02-proto/proto-v1/hello.pb.go @@ -63,7 +63,7 @@ func init() { } type HelloServiceInterface interface { - Hello(in String, out *String) error + Hello(in *String, out *String) error } func RegisterHelloService(srv *rpc.Server, x HelloService) error { @@ -87,7 +87,7 @@ func DialHelloService(network, address string) (*HelloServiceClient, error) { return &HelloServiceClient{Client: c}, nil } -func (p *HelloServiceClient) Hello(in String, out *String) error { +func (p *HelloServiceClient) Hello(in *String, out *String) error { return p.Client.Call("HelloService.Hello", in, out) } diff --git a/examples/ch4-02-proto/protoc-gen-go-netrpc/netprpc.go b/examples/ch4-02-proto/protoc-gen-go-netrpc/netprpc.go index 0df1934..dc65263 100644 --- a/examples/ch4-02-proto/protoc-gen-go-netrpc/netprpc.go +++ b/examples/ch4-02-proto/protoc-gen-go-netrpc/netprpc.go @@ -1,4 +1,4 @@ -// Copyright 2013 . All rights reserved. +// Copyright 2018 . All rights reserved. // Use of this source code is governed by a BSD-style // license that can be found in the LICENSE file. @@ -6,12 +6,16 @@ package main import ( "bytes" + "log" "text/template" - "github.com/golang/protobuf/protoc-gen-go/descriptor" "github.com/golang/protobuf/protoc-gen-go/generator" ) +func init() { + generator.RegisterPlugin(new(netrpcPlugin)) +} + type netrpcPlugin struct{ *generator.Generator } func (p *netrpcPlugin) Name() string { return "netrpc" } @@ -25,81 +29,35 @@ func (p *netrpcPlugin) GenerateImports(file *generator.FileDescriptor) { func (p *netrpcPlugin) Generate(file *generator.FileDescriptor) { for _, svc := range file.Service { - p.genServiceInterface(file, svc) - p.genServiceServer(file, svc) - p.genServiceClient(file, svc) + spec := p.buildServiceSpec(svc) + + var buf bytes.Buffer + t := template.Must(template.New("").Parse(tmplService)) + err := t.Execute(&buf, spec) + if err != nil { + log.Fatal(err) + } + + p.P(buf.String()) } } -func (p *netrpcPlugin) genServiceInterface( - file *generator.FileDescriptor, - svc *descriptor.ServiceDescriptorProto, -) { - const serviceInterfaceTmpl = ` +const tmplService = ` +{{$root := .}} + type {{.ServiceName}}Interface interface { - {{.CallMethodList}} -} -` - const callMethodTmpl = ` -{{.MethodName}}(in {{.ArgsType}}, out *{{.ReplyType}}) error` - - // gen call method list - var callMethodList string - for _, m := range svc.Method { - out := bytes.NewBuffer([]byte{}) - t := template.Must(template.New("").Parse(callMethodTmpl)) - t.Execute(out, &struct{ ServiceName, MethodName, ArgsType, ReplyType string }{ - ServiceName: generator.CamelCase(svc.GetName()), - MethodName: generator.CamelCase(m.GetName()), - ArgsType: p.TypeName(p.ObjectNamed(m.GetInputType())), - ReplyType: p.TypeName(p.ObjectNamed(m.GetOutputType())), - }) - callMethodList += out.String() - - p.RecordTypeUse(m.GetInputType()) - p.RecordTypeUse(m.GetOutputType()) - } - - // gen all interface code - { - out := bytes.NewBuffer([]byte{}) - t := template.Must(template.New("").Parse(serviceInterfaceTmpl)) - t.Execute(out, &struct{ ServiceName, CallMethodList string }{ - ServiceName: generator.CamelCase(svc.GetName()), - CallMethodList: callMethodList, - }) - p.P(out.String()) - } + {{- range $_, $m := .MethodList}} + {{$m.MethodName}}(in *{{$m.InputTypeName}}, out *{{$m.OutputTypeName}}) error + {{- end}} } -func (p *netrpcPlugin) genServiceServer( - file *generator.FileDescriptor, - svc *descriptor.ServiceDescriptorProto, -) { - const serviceHelperFunTmpl = ` func Register{{.ServiceName}}(srv *rpc.Server, x {{.ServiceName}}) error { if err := srv.RegisterName("{{.ServiceName}}", x); err != nil { return err } return nil } -` - { - out := bytes.NewBuffer([]byte{}) - t := template.Must(template.New("").Parse(serviceHelperFunTmpl)) - t.Execute(out, &struct{ PackageName, ServiceName, ServiceRegisterName string }{ - PackageName: file.GetPackage(), - ServiceName: generator.CamelCase(svc.GetName()), - }) - p.P(out.String()) - } -} -func (p *netrpcPlugin) genServiceClient( - file *generator.FileDescriptor, - svc *descriptor.ServiceDescriptorProto, -) { - const clientHelperFuncTmpl = ` type {{.ServiceName}}Client struct { *rpc.Client } @@ -114,42 +72,9 @@ func Dial{{.ServiceName}}(network, address string) (*{{.ServiceName}}Client, err return &{{.ServiceName}}Client{Client: c}, nil } -{{.MethodList}} +{{range $_, $m := .MethodList}} +func (p *{{$root.ServiceName}}Client) {{$m.MethodName}}(in *{{$m.InputTypeName}}, out *{{$m.OutputTypeName}}) error { + return p.Client.Call("{{$root.ServiceName}}.{{$m.MethodName}}", in, out) +} +{{end}} ` - const clientMethodTmpl = ` -func (p *{{.ServiceName}}Client) {{.MethodName}}(in {{.ArgsType}}, out *{{.ReplyType}}) error { - return p.Client.Call("{{.ServiceName}}.{{.MethodName}}", in, out) -} -` - - // gen client method list - var methodList string - for _, m := range svc.Method { - out := bytes.NewBuffer([]byte{}) - t := template.Must(template.New("").Parse(clientMethodTmpl)) - t.Execute(out, &struct{ ServiceName, ServiceRegisterName, MethodName, ArgsType, ReplyType string }{ - ServiceName: generator.CamelCase(svc.GetName()), - ServiceRegisterName: file.GetPackage() + "." + generator.CamelCase(svc.GetName()), - MethodName: generator.CamelCase(m.GetName()), - ArgsType: p.TypeName(p.ObjectNamed(m.GetInputType())), - ReplyType: p.TypeName(p.ObjectNamed(m.GetOutputType())), - }) - methodList += out.String() - } - - // gen all client code - { - out := bytes.NewBuffer([]byte{}) - t := template.Must(template.New("").Parse(clientHelperFuncTmpl)) - t.Execute(out, &struct{ PackageName, ServiceName, MethodList string }{ - PackageName: file.GetPackage(), - ServiceName: generator.CamelCase(svc.GetName()), - MethodList: methodList, - }) - p.P(out.String()) - } -} - -func init() { - generator.RegisterPlugin(new(netrpcPlugin)) -} diff --git a/examples/ch4-02-proto/protoc-gen-go-netrpc/spec.go b/examples/ch4-02-proto/protoc-gen-go-netrpc/spec.go new file mode 100644 index 0000000..0664fbf --- /dev/null +++ b/examples/ch4-02-proto/protoc-gen-go-netrpc/spec.go @@ -0,0 +1,37 @@ +// Copyright 2018 . All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package main + +import ( + "github.com/golang/protobuf/protoc-gen-go/descriptor" + "github.com/golang/protobuf/protoc-gen-go/generator" +) + +type ServiceSpec struct { + ServiceName string + MethodList []ServiceMethodSpec +} + +type ServiceMethodSpec struct { + MethodName string + InputTypeName string + OutputTypeName string +} + +func (p *netrpcPlugin) buildServiceSpec(svc *descriptor.ServiceDescriptorProto) *ServiceSpec { + spec := &ServiceSpec{ + ServiceName: generator.CamelCase(svc.GetName()), + } + + for _, m := range svc.Method { + spec.MethodList = append(spec.MethodList, ServiceMethodSpec{ + MethodName: generator.CamelCase(m.GetName()), + InputTypeName: p.TypeName(p.ObjectNamed(m.GetInputType())), + OutputTypeName: p.TypeName(p.ObjectNamed(m.GetOutputType())), + }) + } + + return spec +}