Use fs.FS

go.mod

@@ -0,0 +1,3 @@
+module git.fuyu.moe/Fuyu/migrate/v2
+
+go 1.16

migrate.go

@@ -5,14 +5,14 @@ import (
 	"database/sql"
 	"errors"
 	"fmt"
+	"io/fs"
 	"strconv"
 )
 
 // Options contains all settings
 type Options struct {
-	TableName   string // Name used for version info table; defaults to DefaultTableName if not set
-	Schema      string // Schema used for version info table; For PostgreSQL, ignored if not set
-	AssetPrefix string
+	TableName string // Name used for version info table; defaults to DefaultTableName if not set
+	Schema    string // Schema used for version info table; For PostgreSQL, ignored if not set
 }
 
 // DefaultTableName is the name used when no TableName is specified in Options
@@ -29,15 +29,20 @@ const fileFormat = `%04d.sql`
 // AssetFunc is a function that returns the data for the given name
 type AssetFunc func(string) ([]byte, error)
 
-// Migrate executes migrations to get to the desired version
+// Migrate executes all migrations
+// Filenames need to have incrementing numbers
 // Downgrading is not supported as it could result in data loss
-func Migrate(db *sql.DB, version int, o Options, asset AssetFunc) error {
+func Migrate(db *sql.DB, o Options, assets fs.FS) error {
+	entries, err := fs.ReadDir(assets, `.`)
+	if err != nil {
+		panic(`failed to read list of files`)
+	}
+	version := len(entries)
+
 	if o.TableName == `` {
 		o.TableName = DefaultTableName
 	}
 
-	var err error
-
 	searchPath := `public`
 	_ = db.QueryRow(`SHOW search_path`).Scan(&searchPath)
 
@@ -74,7 +79,7 @@ func Migrate(db *sql.DB, version int, o Options, asset AssetFunc) error {
 	}
 
 	for i := v + 1; i <= version; i++ {
-		script, err := asset(fmt.Sprintf(o.AssetPrefix+fileFormat, i))
+		script, err := fs.ReadFile(assets, fmt.Sprintf(fileFormat, i))
 		if err != nil {
 			return ErrUpdatesMissing
 		}