initial commit

pkg/db/migration.go

@@ -0,0 +1,60 @@
+// Copyright (C) 2022 Marius Schellenberger
+
+package db
+
+import (
+	"errors"
+
+	"git.giftfish.de/ston1th/goacc/pkg/store"
+)
+
+const (
+	versionKey     = "version/version"
+	currentVersion = 0
+)
+
+type migrator func(*DB, int) error
+
+var migrators = []migrator{
+	func(_ *DB, _ int) error {
+		return nil
+	},
+}
+
+func (db *DB) RunMigrations() (err error) {
+	log := db.log.WithName("migration")
+	var version int
+	err = db.store.Get(versionKey, &version)
+	if err == store.ErrKeyNotFound {
+		err = db.store.Set(versionKey, currentVersion)
+		if err != nil {
+			return
+		}
+		err = db.store.Get(versionKey, &version)
+		if err != nil {
+			return
+		}
+	}
+	log.Info("db versions", "current", version, "new", currentVersion)
+	if currentVersion < version {
+		return errors.New("incompatible versions")
+	}
+	if currentVersion == version {
+		log.Info("nothing to do")
+	}
+	for version < currentVersion {
+		v := version + 1
+		log.Info("running", "version", v)
+		err = migrators[v](db, v)
+		if err != nil {
+			return
+		}
+		err = db.store.Set(versionKey, v)
+		if err != nil {
+			return
+		}
+		version = v
+		log.Info("finished", "version", v)
+	}
+	return
+}