Monkey-Pro / protoc-go-inject-tag

Inject custom tags to protobuf golang struct

protoc-go-inject-tag

Why?

Golang protobuf doesn't support custom tags to generated structs. This script injects custom tags to generated protobuf files, useful for things like validation struct tags.

Install

• protobuf version 3

  For OS X:

  brew install protobuf
  

• go support for protobuf: go get -u github.com/golang/protobuf/{proto,protoc-gen-go}

• go get github.com/favadi/protoc-go-inject-tag or download the binaries from releases page.

Usage

Add a comment with syntax // @inject_tag: custom_tag:"custom_value" before fields to add custom tag to in .proto files.

Example:

// file: test.proto
syntax = "proto3";

package pb;

message IP {
  // @inject_tag: valid:"ip"
  string Address = 1;
}

Generate with protoc command as normal.

protoc --go_out=. test.proto

Run protoc-go-inject-tag with generated file test.pb.go.

protoc-go-inject-tag -input=./test.pb.go

The custom tags will be injected to test.pb.go.

type IP struct {
	// @inject_tag: valid:"ip"
	Address string `protobuf:"bytes,1,opt,name=Address,json=address" json:"Address,omitempty" valid:"ip"`
}

To skip the tag for the generated XXX_* fields, use -XXX_skip=yaml,xml flag.

To enable verbose logging, use -verbose

标签类型说明

1. 作用域优先级: 结构体注解上的标签 < 字段注解上的标签 即：当字段注解上没有改类型的标签说明，则适用结构体注解上的标签规则；当字段注解和结构体注解上都有标签的说明，只使用字段注解上的标签规则。
2. 忽略以XXX_打头的字段名转换
3. 标签值规则, 如下表格：

标签值	说明	示例
"-"	忽略标签值	json:"-"
"#toSnake"	根据字段名转蛇形	json:"field_name"
"#toCamel"	根据字段名转驼峰	json:"FieldName"
"#toCamel2"	根据字段名转驼峰并首字母小写	json:"fieldName"
自定义标签	直接使用该标签	selfTag:"self-tag-value"