add new method

pkg/spanner/migration.go

@@ -20,6 +20,7 @@
 package spanner
 
 import (
+	"embed"
 	"errors"
 	"fmt"
 	"os"
@@ -141,6 +142,68 @@ func LoadMigrations(dir string) (Migrations, error) {
 	return migrations, nil
 }
 
+func LoadMigrationsFromEmbeddedFS(dir string, scripts embed.FS) (Migrations, error) {
+	files, err := scripts.ReadDir(dir)
+	if err != nil {
+		return nil, err
+	}
+
+	var migrations Migrations
+
+	versions := map[uint64]string{}
+
+	for _, f := range files {
+		if f.IsDir() {
+			continue
+		}
+
+		filename := f.Name()
+
+		matches := migrationFileRegex.FindStringSubmatch(filename)
+		if len(matches) != 4 {
+			continue
+		}
+
+		version, err := strconv.ParseUint(matches[1], 10, 64)
+		if err != nil {
+			continue
+		}
+
+		file, err := scripts.ReadFile(filepath.Join(dir, filename))
+		if err != nil {
+			continue
+		}
+
+		statements, err := ddlToStatements(f.Name(), file)
+		if err != nil {
+			nstatements, nerr := dmlToStatements(f.Name(), file)
+			if nerr != nil {
+				return nil, fmt.Errorf("failed to parse DDL/DML statements: %v, %v", err, nerr)
+			}
+			statements = nstatements
+		}
+
+		kind, err := inspectStatementsKind(statements)
+		if err != nil {
+			return nil, err
+		}
+
+		migrations = append(migrations, &Migration{
+			Version:    uint(version),
+			Name:       matches[2],
+			Statements: statements,
+			kind:       kind,
+		})
+
+		if prevFileName, ok := versions[version]; ok {
+			return nil, fmt.Errorf("colliding version number \"%d\" between file names \"%s\" and \"%s\"", version, prevFileName, filename)
+		}
+		versions[version] = filename
+	}
+
+	return migrations, nil
+}
+
 func ddlToStatements(filename string, data []byte) ([]string, error) {
 	ddl, err := spansql.ParseDDL(filename, string(data))
 	if err != nil {