1 files changed, 51 insertions, 0 deletions
diff --git a/backend/db.go b/backend/db.go
new file mode 100644
index 0000000..9ced627
--- /dev/null
+++ b/backend/db.go
@@ -0,0 +1,51 @@
+/*
+ * Database handling
+ *
+ * Copyright (C) 2024  Runxi Yu <https://runxiyu.org>
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package main
+
+import (
+	"context"
+	"errors"
+	"fmt"
+
+	"github.com/jackc/pgx/v5/pgxpool"
+)
+
+var db *pgxpool.Pool
+
+var errUnsupportedDatabaseType = errors.New("unsupported db type")
+
+const pgErrUniqueViolation = "23505"
+
+/*
+ * This must be run during setup, before the database is accessed by any
+ * means. Otherwise, db would be a null pointer.
+ */
+func setupDatabase() error {
+	var err error
+	if config.DB.Type != "postgres" {
+		return errUnsupportedDatabaseType
+	}
+	db, err = pgxpool.New(context.Background(), config.DB.Conn)
+	if err != nil {
+		return fmt.Errorf("error opening database: %w", err)
+	}
+	return nil
+}