fix(agent): fix werkzeug.middleware mod not found

In Werkzeug < 0.15, dispatcher was not in a dedicated module. It was
included in a big wsgi module before it was splitted. This old version
of werkzeug must be fully supported though because it is included in
el8.

fix #419

CHANGELOG.md

@@ -19,6 +19,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - docs: Update configuration reference documentation.
 
 ### Fixed
+- agent: Fix No module named 'werkzeug.middleware' ModuleNotFoundError with
+  Werkzeug < 0.15 (#419→420).
 - frontend: Update dependencies to fix CVE-2024-55565 (nanoid).
 
 ## [4.0.0] - 2024-11-28

slurmweb/apps/agent.py

@@ -10,7 +10,15 @@
 from rfl.web.tokens import RFLTokenizedRBACWebApp
 from racksdb.errors import RacksDBSchemaError, RacksDBFormatError
 from racksdb.web.app import RacksDBWebBlueprint
-from werkzeug.middleware import dispatcher
+
+try:
+    from werkzeug.middleware import dispatcher
+except ModuleNotFoundError:
+    # In Werkzeug < 0.15, dispatcher was not in a dedicated module, it was included in a
+    # big wsgi module. This old version of werkzeug must be fully supported because it
+    # is included in el8. See https://github.com/rackslab/Slurm-web/issues/419 for
+    # reference.
+    from werkzeug import wsgi as dispatcher
 
 from . import SlurmwebWebApp
 from ..version import get_version