misc: improve get_safe_db_name (#72643)

hobo/test_utils.py

@@ -1,7 +1,24 @@
+# hobo - portal to configure and deploy applications
+# Copyright (C) 2022  Entr'ouvert
+#
+# 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 <http://www.gnu.org/licenses/>.
+
+import hashlib
 import os
 
 
-def get_safe_db_name():
+def get_safe_db_name(max_length=53):
     """
     PostgreSQL database name limit is 63 characters, which can become
     an issue during testing, because we need to build a unique
@@ -19,4 +36,14 @@ def get_safe_db_name():
         # when we're in parallel mode, pytest-django will do this
         # for us at a later point
         parts.append(os.environ.get('TOX_ENV_NAME'))
-    return '_'.join(parts)
+    full_db_name = '_'.join(parts)
+    if len(full_db_name) < max_length:
+        return full_db_name
+    hashcode_length = 8
+    hashcode = hashlib.md5(full_db_name.encode()).hexdigest()[: hashcode_length - 2]
+    prefix_length = (max_length - hashcode_length) - (max_length - hashcode_length) // 2
+    suffix_length = (max_length - hashcode_length) // 2
+    assert hashcode_length + prefix_length + suffix_length == max_length
+    truncated_db_name = full_db_name[:prefix_length] + '_' + hashcode + '_' + full_db_name[-suffix_length:]
+    assert len(truncated_db_name) == max_length
+    return truncated_db_name