work around nasty characters as part of the database password

forgejo.json.sample

@@ -9,8 +9,6 @@
         "TIME_FORMAT": "utcnow:%Y-%m-%d_%H:%M:%S",
         "REPO_SUBDIR": "forgejo",
         "MYSQL_DB": "database name",
-        "MYSQL_USER": "database user required for dumping the database",
-        "MYSQL_PASSWORD": "password required for dumping the database "
     },
     "remotes": [
         {

forgejo_backup

@@ -55,11 +55,13 @@ class ForgejoManager(backup_manager.BackupManager):
         return True
 
     def dump_database(self):
-        password = self._common["MYSQL_PASSWORD"]
-        user = self._common["MYSQL_USER"]
         db = self._common["MYSQL_DB"]
-
-        cmd = f"docker compose exec -i --user 1000:1000 db mariadb-dump --single-transaction --default-character-set=utf8mb4 -h localhost -u {user} --password={password} {db} > mysql/forgejo.sql"
+        # we assume that a [client] conf as default for user and password is mounted inside the mysql directory of the container
+        # e.g.:
+        # [client]
+        # user=<theusername>
+        # password=<thepassword>
+        cmd = f"docker compose exec -it db sh -c 'mariadb-dump --defaults-extra-file=/var/lib/mysql/forgejo-mysql.conf {db} > /var/lib/mysql/forgejo.sql'"
         try:
             result = subprocess.run(
                 cmd,