proto-go-sql | Generate SQL Scanner and Valuer implementations | Serialization library

The scanner and valuer interfaces are not really things you'll use yourself, not when it comes to storing custom types in a DB, at least. I'll first cover the use of the Scan() and Value() functions, then I'll address your issues.

When you get a sql.Row result, and want to assign (scan) the values from the result set into your variables of a custom type. The docs show the sql.Row.Scan() function takes 0 or more arguments of type interface{}, basically anything. (check docs here).

In the list of supported types into which values can be scanned, the last line is the important one:

any type implementing Scanner (see Scanner docs)

With the function func (ts *Timestamp) Scan(value interface{}) error {, the Timestamp type now implements the Scanner interface, thus allowing sql.Row to assign values to this type. The documentation for the Scanner interface is located right below the docs for Scan(), which I linked above.

Of course, that helps you to read values from the DB, gets you nowhere when it comes to storing these types. For that, you need the Valuer interface. In case you haven't guessed it yet, the func (ts Timestamp) Value() (driver.Value, error) function indeed makes it so your Timestamp type implements this interface. The documentation for the driver.Valuer interface can be found here, all the way at the bottom.

The point of the Valuer interface is to allow a way to convert any type to a driver.Value, that the driver can work with and store in the DB (again: docs here).

First up, I'm goign to have to assume your protoc output is written to the v1 package. If it isn't, it's not going to work very well for you.

The offending line is indeed the one you marked out: