What's the idiomatic way to work with dates without time in golang?

Question

I'm writing a REST API in Go, working with dates that don't represent a single point in time.

It's JSON data going to and from the server in "2006-01-02" format, with that data talking to a mysql database using DATE columns.

One thing I've tried is to create a struct that embeds a Time, and implements JSON and SQL conversion interface implementations to be able to correctly interact with the endpoints while still having Time methods available for date math and formatting. e.g.:

package localdate  import (     "time"     "encoding/json"     "database/sql/driver" )  type LocalDate struct {     time.Time }  func NewLocalDate(year int, month time.Month, day int) LocalDate {     time := time.Date(year, month, day, 0, 0, 0, 0, time.UTC)     return LocalDate{Time: time} }  const LocalDateFormat = "2006-01-02" // yyyy-mm-dd  func (ld *LocalDate) UnmarshalJSON(data []byte) error {     // parse and set the ld.Time variable }  func (ld *LocalDate) MarshalJSON() ([]byte, error) {     return json.Marshal(ld.Format(LocalDateFormat)) }  // sql.Scanner implementation to convert a time.Time column to a LocalDate func (ld *LocalDate) Scan(value interface{}) error {}  // sql/driver.Valuer implementation to go from LocalDate -> time.Time func (ld *LocalDate) Value() (driver.Value, error)  {}  // used to convert a LocalDate into something we can plug into a query // we could just use ld.Time, but that would send '2015-01-01 00:00:00 +0000 UTC' // instead of '2015-01-01' for the DATE query parameter.  (Which works for mysql, but is officially invalid SQL) func (ld *LocalDate) SqlDate() string  {     return ld.Format(LocalDateFormat) } 

And then other structs can be of this type, and get 90% there to representing the date type in my problem domain.

The above code works, but I feel like I'm fighting against the Go current. So a couple questions for the veterans of the language:

Do you think this code will cause more pain than it'll save?
If so, what style would you recommend?

Answer 1

I use civil.Date from the package cloud.google.com/go/civil

Answer 2

I think you can store your data as time.Time but convert it to a string for JSON purposes:

type LocalDate struct {   t time.Time `json:",string"` // might even work anonymously here } 

To see how to make this work with SQL: https://github.com/go-sql-driver/mysql#timetime-support