GET /model/controller/api BAD Request 400

[Deezzir]

Description

The library failed to connect to the controller with 400 HTTP code

File "/var/lib/juju/agents/unit-juju-backup-all-1/charm/venv/juju/controller.py", line 641, in get_model
    await model._connect_direct(**kwargs)
  File "/var/lib/juju/agents/unit-juju-backup-all-1/charm/venv/juju/model/__init__.py", line 837, in _connect_direct
    await self._connector.connect(**kwargs)
  File "/var/lib/juju/agents/unit-juju-backup-all-1/charm/venv/juju/client/connector.py", line 107, in connect
    self._connection = await Connection.connect(**kwargs)
  File "/var/lib/juju/agents/unit-juju-backup-all-1/charm/venv/juju/client/connection.py", line 261, in connect
    await self._connect_with_redirect([_ep])
  File "/var/lib/juju/agents/unit-juju-backup-all-1/charm/venv/juju/client/connection.py", line 832, in _connect_with_redirect
    login_result = await self._connect_with_login(endpoints)
  File "/var/lib/juju/agents/unit-juju-backup-all-1/charm/venv/juju/client/connection.py", line 800, in _connect_with_login
    await self._connect(endpoints)
  File "/var/lib/juju/agents/unit-juju-backup-all-1/charm/venv/juju/client/connection.py", line 743, in _connect
    result = await task
  File "/usr/lib/python3.10/asyncio/tasks.py", line 571, in _wait_for_one
    return f.result()  # May raise f.exception().
  File "/var/lib/juju/agents/unit-juju-backup-all-1/charm/venv/juju/client/connection.py", line 729, in _try_endpoint
    return await self._open(endpoint, cacert)
  File "/var/lib/juju/agents/unit-juju-backup-all-1/charm/venv/juju/client/connection.py", line 333, in _open
    await websockets.connect(
  File "/var/lib/juju/agents/unit-juju-backup-all-1/charm/venv/websockets/asyncio/client.py", line 543, in __await_impl__
    await self.connection.handshake(
  File "/var/lib/juju/agents/unit-juju-backup-all-1/charm/venv/websockets/asyncio/client.py", line 114, in handshake
    raise self.protocol.handshake_exc
  File "/var/lib/juju/agents/unit-juju-backup-all-1/charm/venv/websockets/client.py", line 325, in parse
    self.process_response(response)
  File "/var/lib/juju/agents/unit-juju-backup-all-1/charm/venv/websockets/client.py", line 142, in process_response
    raise InvalidStatus(response)

Some debug logs:

2025-04-23 10:32:04,331 INFO jujubackupall.backup [juju-3-5-ctrl] Attempt #1 for controller backup.
2025-04-23 10:32:04,331 DEBUG websockets.client > TEXT '{\n  "type": "ModelManager",\n  "request": "Lis...\n  "request-id": 20\n}' [171 bytes]
2025-04-23 10:32:04,355 DEBUG websockets.client < TEXT '{"request-id":20,"response":{"results":[{"resul...version":"3.5.4"}}]}}\n' [714 bytes]
2025-04-23 10:32:04,358 DEBUG websockets.client = connection is CONNECTING
2025-04-23 10:32:04,368 DEBUG websockets.client > GET /model/controller/api HTTP/1.1
2025-04-23 10:32:04,368 DEBUG websockets.client > Host: 10.169.129.133:17070
2025-04-23 10:32:04,368 DEBUG websockets.client > Upgrade: websocket
2025-04-23 10:32:04,368 DEBUG websockets.client > Connection: Upgrade
2025-04-23 10:32:04,368 DEBUG websockets.client > Sec-WebSocket-Key: FEDyzd+Bef3hsnqP6uhUwA==
2025-04-23 10:32:04,368 DEBUG websockets.client > Sec-WebSocket-Version: 13
2025-04-23 10:32:04,368 DEBUG websockets.client > Sec-WebSocket-Extensions: permessage-deflate; client_max_window_bits
2025-04-23 10:32:04,368 DEBUG websockets.client > User-Agent: Python/3.10 websockets/15.0.1
2025-04-23 10:32:04,369 DEBUG websockets.client < HTTP/1.1 400 Bad Request
2025-04-23 10:32:04,369 DEBUG websockets.client < Content-Type: text/plain; charset=utf-8
2025-04-23 10:32:04,369 DEBUG websockets.client < X-Content-Type-Options: nosniff
2025-04-23 10:32:04,369 DEBUG websockets.client < Date: Wed, 23 Apr 2025 10:32:04 GMT
2025-04-23 10:32:04,369 DEBUG websockets.client < Content-Length: 32
2025-04-23 10:32:04,369 DEBUG websockets.client < [body] (32 bytes)
2025-04-23 10:32:04,369 DEBUG websockets.client > EOF
2025-04-23 10:32:04,369 DEBUG websockets.client x closing TCP connection
2025-04-23 10:32:04,370 DEBUG websockets.client < EOF
2025-04-23 10:32:04,370 DEBUG websockets.client = connection is CLOSED
2025-04-23 10:32:04,370 DEBUG websockets.client > CLOSE 1000 (OK) [2 bytes]
2025-04-23 10:32:04,370 DEBUG websockets.client = connection is CLOSING
2025-04-23 10:32:04,371 DEBUG websockets.client < CLOSE 1000 (OK) [2 bytes]
2025-04-23 10:32:04,371 DEBUG websockets.client < EOF
2025-04-23 10:32:04,371 DEBUG websockets.client > EOF
2025-04-23 10:32:04,371 DEBUG websockets.client = connection is CLOSED
2025-04-23 10:32:04,374 DEBUG __main__ writing error details to the results file
2025-04-23 10:32:04,375 ERROR __main__ backup failed! check log for details

Reference: canonical/charm-juju-backup-all#86

Urgency

Client presentation, help now please!

Python-libjuju version

3.6.1.1

Juju version

3.5.4

Reproduce / Test

Run the latest/stable charm, rev70 charm-juju-backup-all on a Juju controller with version 3.5.4

[Deezzir]

Can I get any feedback on the issue? Is it a problem with the library, oris its something wrong on the side of the library user

[dimaqq]

The client gets HTTP 400 during websocket upgrade...

It's hard to say why without the controller logs, ideally at TRACE level for some subsystem(s), or in fact for the whole controller.

[dimaqq]

https://discourse.charmhub.io/t/how-to-use-juju-to-debug-logs/10806

[H-M-Quang-Ngo]

I think this is the root cause:

python-libjuju/juju/controller.py

Lines 627 to 634 in 19bacb9

	async def get_model(self, model):
	"""Get a model by name or UUID.
	:param str model: Model name or UUID
	:returns Model: Connected Model instance.
	"""
	uuids = await self.model_uuids()
	uuid = uuids.get(model) or model

line 634 - if the model name doesn't exist in the dict, the model name is used as the model uuid instead.

Here the websocket url expects an uuid:

python-libjuju/juju/client/connection.py

Lines 317 to 318 in 19bacb9

	elif self.uuid:
	url = f"wss://{endpoint}/model/{self.uuid}/api"

so the /model/controller/api is likely invalid - it should be /model/<controller-uuid>/api. Juju will reject with 400 httpbad request and that is raised as websocket InvalidStatus.