I have a struct that looks like this:

type DataPoint struct {
    Config struct {
        ...
        ReferenceTimestamp       time.Time `json:"referenceTimestamp" binding:"required"`
    } `json:"config" binding:"required"`

    Measurement []struct {
        ...
        Timestamp     time.Time `json:"timestamp" binding:"required"`
    } `json:"measurements" binding:"required,dive"`
}

I would like to validate that the value of the Timestamp attribute in the Measurement slice is before the value of the ReferenceTimestamp in the Config struct.

How can I achieve this with go-playground/validator (v10) + gin?

I tried to use the gtcsfield (Config.ReferenceTimestamp) and ltcsfield (Measurement.Timestamp) tags but it doesn’t seem to work.

I was able to make it work with a custom validator (StructLevel), but I would like to know if there is a way to do this with the built-in tags.