Use Gozz to Manage Your Golang Struct Field Tags Formats Automatically

In Go developing, we would design structs and fill their struct tag in many case. 

For example, json:something for json marshal and unmarshal:

package x

type T struct{
    MyField string `json:"my_field"`
}

As we known, naming is a big problem in programing. When we fill these tag, we would face these questions as follows:

• Which case should use, camelCase or snake_case ?
• If camelCase used. how to format words like UserID ? userId or userID ?
• Struct fields could be added and their name could be modified also. How to quickly updated these field tag as format your desired, and may be there would be many tag to update.
• If project would be cooperated with peoples. How to ensure every members would follow these convention, and never need to remind these rules again and again.

Even we could design lint tool to validate these tag is whether desired in our pipeline, but I believe that : The best way to manage these struct fields tags is never manage it in manually, but in instrumentally.

You could try Gozz to do this more simply:

Here is a normal case, we want to add json and bson tag for our struct.

package tag01

// +zz:tag:json,bson:{{ snake .FieldName }}
type User struct {
    Id        string
    Name      string
    Address   string
    CreatedAt time.Time
    UpdatedAt time.Time
}

add the annotation on struct : +zz:tag:json,bson:{{ snake .FieldName}}

and then execute gozz run -p "tag" ./ 

You would find out these stuff is solved and nobody would be troubled anymore.

 

package tag01

// +zz:tag:json,bson:{{ snake .FieldName }}
type User struct {
    Id        string    `bson:"id" json:"id"`
    Name      string    `bson:"name" json:"name"`
    Address   string    `bson:"address" json:"address"`
    CreatedAt time.Time `bson:"created_at" json:"created_at"`
    UpdatedAt time.Time `bson:"updated_at" json:"updated_at"`
}

Just put these script in project’s makefile and execute them in projects’s build pipeline or commit hooks. Time Is Saved.

The upper example show what is the basic usage of gozz-tag, this example would show how it strong could be:

• It placed the annotation both on block declaration ,struct declaration, and also struct field.
• And it use different cases and pipeline method in go-template  

// +zz:tag:json,bson:{{ snake .FieldName }}
type (
    User struct {
        Id        string
        Name      string
        Address   string
        CreatedAt time.Time
        UpdatedAt time.Time
    }

    // +zz:tag:json,bson:{{ camel .FieldName }}
    Book struct {
        Id        string
        Title     string
        CreatedAt time.Time
        UpdatedAt time.Time
    }

    Order struct {
        Id     string
        UserId string
        BookId string
        // +zz:tag:json,bson:{{ upper .FieldName | upper }}
        CreatedAt time.Time
        // +zz:tag:+json:,omitempty
        UpdatedAt time.Time
    }
)

Execute gozz again and see what is happened:

// +zz:tag:json,bson:{{ snake .FieldName }}
type (
    User struct {
        Id        string    `bson:"id" json:"id"`
        Name      string    `bson:"name" json:"name"`
        Address   string    `bson:"address" json:"address"`
        CreatedAt time.Time `bson:"created_at" json:"created_at"`
        UpdatedAt time.Time `bson:"updated_at" json:"updated_at"`
    }

    // +zz:tag:json,bson:{{ camel .FieldName }}
    Book struct {
        Id        string    `bson:"id" json:"id"`
        Title     string    `bson:"title" json:"title"`
        CreatedAt time.Time `bson:"createdAt" json:"createdAt"`
        UpdatedAt time.Time `bson:"updatedAt" json:"updatedAt"`
    }

    Order struct {
        Id     string `bson:"id" json:"id"`
        UserId string `bson:"user_id" json:"user_id"`
        BookId string `bson:"book_id" json:"book_id"`
        // +zz:tag:json,bson:{{ snake .FieldName | upper }}
        CreatedAt time.Time `bson:"CREATED_AT" json:"CREATED_AT"`
        // +zz:tag:+json:,omitempty
        UpdatedAt time.Time `bson:"updated_at" json:"updated_at,omitempty"`
    }
)

Every different needs was solved.

Some I believe that, with the help of Gozz , we do not need to manage every struct fields in coding , just put them to Gozz and pipeline.

Actually, this function is just one of the builtin plugins of Gozz , it provides many other more awesome plugins to help us improve developing with the help of annotations, such as autowired , api routing , orm structure generation .

Just checkout to github and documentation , and it’s welcome to give us a star .