model: Initial database version injection

If the database was empty on startup a metadata table with a key and
value row is created.

In addition the Ceres executable version is inserted as value under the
key 'version'.

This allows to detect on not-empty databases which Ceres version was
used before which is the starting point to implement migrations.

2 files changed, 21 insertions, 2 deletions

diff --git a/main.go b/main.go
index 6c123da..4abe9ae 100644
--- a/main.go
+++ b/main.go
@@ -35,7 +35,7 @@ func main() {
 
 	model.ConnectDatabase(filepath.Join(storage.Path, "ceres.sqlite3"))
 	defer model.DisconnectDatabase()
-	model.MigrateDatabase()
+	model.MigrateDatabase(version)
 	model.InjectTestRecipes()
 
 	server := NewServer(config.HttpAddress)
diff --git a/model/database.go b/model/database.go
index 16a6cea..cdded4a 100644
--- a/model/database.go
+++ b/model/database.go
@@ -78,10 +78,29 @@ func isDatabaseEmpty(tx *sql.Tx) bool {
 	return number == 0
 }
 
-func MigrateDatabase() {
+func setupMinimalDatabase(tx *sql.Tx, version string) error {
+	cmd := `
+CREATE TABLE metadata (
+	key   TEXT PRIMARY KEY,
+	value TEXT
+);
+INSERT INTO metadata
+	(key, value)
+VALUES
+	('version', ?);
+`
+	_, err := tx.Exec(cmd, version)
+	return err
+}
+
+func MigrateDatabase(version string) {
 	err := Transaction(func(tx *sql.Tx) error {
 		if isDatabaseEmpty(tx) {
 			log.Println("Starting with empty database")
+			err := setupMinimalDatabase(tx, version)
+			if err != nil {
+				log.Fatalf("Failed to setup minimal database schema: %v", err)
+			}
 		}
 
 		query, err := GetSql(`migrate`)