Boostport/migration

//go:build go1.16
// +build go1.16

package migration

import (
    "bytes"
    "embed"
    "fmt"
    "io"
    "io/fs"
    "path"
)

// EmbedMigrationSource uses an embed.FS that is used to embed files natively in Go 1.16+
type EmbedMigrationSource struct {
    EmbedFS embed.FS

    // The path in the embed FS to use
    Dir string
}

// ListMigrationFiles returns a list of embedded migration files
func (e EmbedMigrationSource) ListMigrationFiles() ([]string, error) {

    var f fs.FS = e.EmbedFS

    if e.Dir != "" {

        var err error

        f, err = fs.Sub(f, e.Dir)

        if err != nil {
            return nil, fmt.Errorf("error opening subdirectory in embed fs: %s", err)
        }

    }

    files, err := fs.ReadDir(f, ".")

    if err != nil {
        return nil, fmt.Errorf("error reading directory from embed fs: %w", err)
    }

    var migrations []string

    for _, file := range files {

        if file.IsDir() {
            continue
        }

        migrations = append(migrations, file.Name())
    }

    return migrations, nil
}

// GetMigrationFile gets an embedded migration file
func (e EmbedMigrationSource) GetMigrationFile(name string) (io.Reader, error) {
    file, err := fs.ReadFile(e.EmbedFS, path.Join(e.Dir, name))
    return bytes.NewReader(file), err
}