Using Go 1.16 io/fs as a source for DB migrations

[fasmat]

With golang 1.16 the io/fs package was introduced that among other things allows the use of embedded files in go programs.

Is it already possible to embed migrations into a binary and execute them with golang-migrate?

I'm not yet using golang-migrate but I'm looking for a library that can potentially do this. I've seen that golang-migrate has this interface https://pkg.go.dev/github.com/golang-migrate/migrate/v4/source#Driver. I assume one would need to write a driver implementing the interface and mapping onto https://golang.org/pkg/io/fs/#FS to use golang 1.16 embedded files?

[nekinie]

Posting this just in-case it helps someone, I'm using embed but you could in theory use any file system.

package migrations

import (
	"embed"
	"net/http"

	"github.com/golang-migrate/migrate/v4/source"
	"github.com/golang-migrate/migrate/v4/source/httpfs"
)

//go:embed *.sql
var static embed.FS

func init() {
	source.Register("embed", &driver{})
}

type driver struct {
	httpfs.PartialDriver
}

func (d *driver) Open(rawURL string) (source.Driver, error) {
	err := d.PartialDriver.Init(http.FS(static), ".")
	if err != nil {
		return nil, err
	}

	return d, nil
}

and

driver, err := cassandra.WithInstance(session, config)
if err != nil {
	return err
}

migrator, err := migrate.NewWithDatabaseInstance("embed://", "cassandra", driver)
if err != nil {
	return err
}

[dhui]

Looks like you've discovered the httpfs source driver.
Also, if you want to track io/fs integration progress, see: #471