gtag

Help you to get golang struct's tags elegantly.

Installing

Install gtag by running:

go get -u github.com/wolfogre/gtag/cmd/gtag

and ensuring that $GOPATH/bin is added to your $PATH.

Tutorial

1. define your struct

A source file user.go:

package tutorial

type User struct {
	Id    int    `bson:"_id"`
	Name  string `bson:"name"`
	Email string `bson:"email"`
}

2. run gtag

Run

gtag -types User -tags bson .

and you will get file user_tag.go:

// Code generated by gtag. DO NOT EDIT.
// See: https://github.com/wolfogre/gtag

//go:generate gtag -types User -tags bson .
package tutorial

import (
	"reflect"
	"strings"
)

var (
	// ...
)

// UserTags indicate tags of type User
type UserTags struct {
	Id    string // `bson:"_id"`
	Name  string // `bson:"name"`
	Email string // `bson:"email"`
}

// Tags return specified tags of User
func (*User) Tags(tag string, convert ...func(string) string) UserTags {
	conv := func(in string) string { return strings.TrimSpace(strings.Split(in, ",")[0]) }
	if len(convert) > 0 {
		conv = convert[0]
	}
	if conv == nil {
		conv = func(in string) string { return in }
	}
	return UserTags{
		Id:    conv(tagOfUserId.Get(tag)),
		Name:  conv(tagOfUserName.Get(tag)),
		Email: conv(tagOfUserEmail.Get(tag)),
	}
}

// TagsBson is alias of Tags("bson")
func (*User) TagsBson() UserTags {
	var v *User
	return v.Tags("bson")
}

3. use it

Now you can use the generated code to get tags elegantly:

// update mongo document
obj := User{}
tags := obj.TagsBson()

_, err := collection.UpdateOne(
    ctx,
    bson.M{tags.Id: id},
    bson.M{
        "$set", bson.M{
            tags.Name: name,
            tags.Email: email,
        },
    },
)

Project status

Gtag is beta and is considered feature complete.