initial commit

pkg/db/migration.go

@@ -0,0 +1,48 @@
+package db
+
+import (
+	"git.giftfish.de/ston1th/docstore/pkg/log"
+	"git.giftfish.de/ston1th/docstore/pkg/store"
+)
+
+const (
+	versionKey     = "version/version"
+	currentVersion = 1
+)
+
+type migrator func(*DB) (int, error)
+
+var migrators = []migrator{
+	func(db *DB) (int, error) {
+		return 0, nil
+	},
+}
+
+func (db *DB) RunMigrations() (err error) {
+	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.Printf("db: database version %d", version)
+	for version < currentVersion {
+		v := version + 1
+		log.Printf("db: running migration %d", v)
+		version, err = migrators[v](db)
+		if err != nil {
+			return
+		}
+		err = db.store.Set(versionKey, version)
+		if err != nil {
+			return
+		}
+	}
+	return
+}