protobuf-go/cmd/protoc-gen-go/main.go
Joe Tsai e471641887 cmd/protoc-gen-go: support --help flag
When someone has no idea what a binary does, it is convention to
pass the "--help" flag. When done, we should point the user
to the devsite documentation on protoc with protoc-gen-go.

Change-Id: I36289a1ae025b9e12521b34362370aba5235a44b
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/302330
Trust: Joe Tsai <joetsai@digital-static.net>
Reviewed-by: Damien Neil <dneil@google.com>
2021-03-16 20:24:12 +00:00

57 lines
1.7 KiB
Go

// Copyright 2018 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// The protoc-gen-go binary is a protoc plugin to generate Go code for
// both proto2 and proto3 versions of the protocol buffer language.
//
// For more information about the usage of this plugin, see:
// https://developers.google.com/protocol-buffers/docs/reference/go-generated
package main
import (
"errors"
"flag"
"fmt"
"os"
"path/filepath"
gengo "google.golang.org/protobuf/cmd/protoc-gen-go/internal_gengo"
"google.golang.org/protobuf/compiler/protogen"
"google.golang.org/protobuf/internal/version"
)
const genGoDocURL = "https://developers.google.com/protocol-buffers/docs/reference/go-generated"
const grpcDocURL = "https://grpc.io/docs/languages/go/quickstart/#regenerate-grpc-code"
func main() {
if len(os.Args) == 2 && os.Args[1] == "--version" {
fmt.Fprintf(os.Stdout, "%v %v\n", filepath.Base(os.Args[0]), version.String())
os.Exit(0)
}
if len(os.Args) == 2 && os.Args[1] == "--help" {
fmt.Fprintf(os.Stdout, "See "+genGoDocURL+" for usage information.\n")
os.Exit(0)
}
var (
flags flag.FlagSet
plugins = flags.String("plugins", "", "deprecated option")
)
protogen.Options{
ParamFunc: flags.Set,
}.Run(func(gen *protogen.Plugin) error {
if *plugins != "" {
return errors.New("protoc-gen-go: plugins are not supported; use 'protoc --go-grpc_out=...' to generate gRPC\n\n" +
"See " + grpcDocURL + " for more information.")
}
for _, f := range gen.Files {
if f.Generate {
gengo.GenerateFile(gen, f)
}
}
gen.SupportedFeatures = gengo.SupportedFeatures
return nil
})
}