Weird behaviour when using Kubernetes servers with a non-root api base path

[jacobtomlinson]

Which project are you reporting a bug for?

kr8s

What happened?

To reproduce this bug we need a Kubernetes server running on some base URL other than /. A quick way to do this is with kubectl.

$ kubectl proxy --api-prefix=/somepath/
Starting to serve on 127.0.0.1:8001

Now if we get pods for all namespaces we see an error.

import kr8s
api = kr8s.api(url="http://127.0.0.1:8001/somepath/", namespace=kr8s.ALL)
api.get("pods")

---------------------------------------------------------------------------
HTTPStatusError                           Traceback (most recent call last)
Cell In[3], line 3
      1 import kr8s
      2 api = kr8s.api(url="http://127.0.0.1:8001/somepath/", namespace=kr8s.ALL)
----> 3 api.get("pods")

File ~/Projects/kr8s-org/kr8s/kr8s/_io.py:75, in run_sync.<locals>.wrapped(*args, **kwargs)
     73 portal = Portal()
     74 if inspect.iscoroutinefunction(coro):
---> 75     return portal.call(wrapped)
     76 raise TypeError(f"Expected coroutine function, got {coro.__class__.__name__}")

File ~/Projects/kr8s-org/kr8s/kr8s/_io.py:50, in Portal.call(self, func, *args, **kwargs)
     48 while not self._portal:
     49     pass
---> 50 return self._portal.call(func, *args, **kwargs)

File ~/miniconda3/envs/kr8s/lib/python3.11/site-packages/anyio/from_thread.py:288, in BlockingPortal.call(self, func, *args)
    273 def call(
    274     self,
    275     func: Callable[[Unpack[PosArgsT]], Awaitable[T_Retval] | T_Retval],
    276     *args: Unpack[PosArgsT],
    277 ) -> T_Retval:
    278     """
    279     Call the given function in the event loop thread.
    280 
   (...)
    286 
    287     """
--> 288     return cast(T_Retval, self.start_task_soon(func, *args).result())

File ~/miniconda3/envs/kr8s/lib/python3.11/concurrent/futures/_base.py:456, in Future.result(self, timeout)
    454     raise CancelledError()
    455 elif self._state == FINISHED:
--> 456     return self.__get_result()
    457 else:
    458     raise TimeoutError()

File ~/miniconda3/envs/kr8s/lib/python3.11/concurrent/futures/_base.py:401, in Future.__get_result(self)
    399 if self._exception:
    400     try:
--> 401         raise self._exception
    402     finally:
    403         # Break a reference cycle with the exception in self._exception
    404         self = None

File ~/miniconda3/envs/kr8s/lib/python3.11/site-packages/anyio/from_thread.py:217, in BlockingPortal._call_func(self, func, args, kwargs, future)
    214         else:
    215             future.add_done_callback(callback)
--> 217         retval = await retval_or_awaitable
    218 else:
    219     retval = retval_or_awaitable

File ~/Projects/kr8s-org/kr8s/kr8s/_api.py:344, in Api.get(self, kind, namespace, label_selector, field_selector, as_object, *names, **kwargs)
    309 async def get(
    310     self,
    311     kind: Union[str, type],
   (...)
    317     **kwargs,
    318 ) -> List[object]:
    319     """
    320     Get Kubernetes resources.
    321 
   (...)
    342         The resources.
    343     """
--> 344     return await self._get(
    345         kind,
    346         *names,
    347         namespace=namespace,
    348         label_selector=label_selector,
    349         field_selector=field_selector,
    350         as_object=as_object,
    351         **kwargs,
    352     )

File ~/Projects/kr8s-org/kr8s/kr8s/_api.py:370, in Api._get(self, kind, namespace, label_selector, field_selector, as_object, *names, **kwargs)
    366     group, version = as_object.version.split("/")
    367     headers[
    368         "Accept"
    369     ] = f"application/json;as={as_object.kind};v={version};g={group}"
--> 370 async with self._get_kind(
    371     kind,
    372     namespace=namespace,
    373     label_selector=label_selector,
    374     field_selector=field_selector,
    375     headers=headers or None,
    376     **kwargs,
    377 ) as (obj_cls, response):
    378     resourcelist = response.json()
    379     if (
    380         as_object
    381         and "kind" in resourcelist
    382         and resourcelist["kind"] == as_object.kind
    383     ):

File ~/miniconda3/envs/kr8s/lib/python3.11/contextlib.py:204, in _AsyncGeneratorContextManager.__aenter__(self)
    202 del self.args, self.kwds, self.func
    203 try:
--> 204     return await anext(self.gen)
    205 except StopAsyncIteration:
    206     raise RuntimeError("generator didn't yield") from None

File ~/Projects/kr8s-org/kr8s/kr8s/_api.py:299, in Api._get_kind(self, kind, namespace, label_selector, field_selector, params, watch, **kwargs)
    297     obj_cls = get_class(kind, _asyncio=self._asyncio)
    298 params = params or None
--> 299 async with self.call_api(
    300     method="GET",
    301     url=obj_cls.endpoint,
    302     version=obj_cls.version,
    303     namespace=namespace if obj_cls.namespaced else None,
    304     params=params,
    305     **kwargs,
    306 ) as response:
    307     yield obj_cls, response

File ~/miniconda3/envs/kr8s/lib/python3.11/contextlib.py:204, in _AsyncGeneratorContextManager.__aenter__(self)
    202 del self.args, self.kwds, self.func
    203 try:
--> 204     return await anext(self.gen)
    205 except StopAsyncIteration:
    206     raise RuntimeError("generator didn't yield") from None

File ~/Projects/kr8s-org/kr8s/kr8s/_api.py:135, in Api.call_api(self, method, version, base, namespace, url, raise_for_status, stream, **kwargs)
    133         response = await self._session.request(**kwargs)
    134         if raise_for_status:
--> 135             response.raise_for_status()
    136         yield response
    137 except httpx.HTTPStatusError as e:
    138     # If we get a 401 or 403 our credentials may have expired so we
    139     # reauthenticate and try again a few times before giving up.

File ~/miniconda3/envs/kr8s/lib/python3.11/site-packages/httpx/_models.py:759, in Response.raise_for_status(self)
    757 error_type = error_types.get(status_class, "Invalid status code")
    758 message = message.format(self, error_type=error_type)
--> 759 raise HTTPStatusError(message, request=request, response=self)

HTTPStatusError: Redirect response '301 Moved Permanently' for url 'http://127.0.0.1:8001/somepath/api/v1/namespaces//pods'
Redirect location: '/somepath/api/v1/namespaces/pods'
For more information check: https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/301

Also if I omit the namespace (or set it to None) I get Pods for all namespaces, but I should only get them for the current namespace.

>>> import kr8s
>>> api = kr8s.api(url="http://127.0.0.1:8001/somepath/")
>>> for pod in api.get("pods"):
...     print(f"{pod.namespace}\t{pod.name}")
kube-system     coredns-76f75df574-5gw8n
kube-system     coredns-76f75df574-9466n
kube-system     etcd-pytest-kind-control-plane
kube-system     kindnet-t24wd
kube-system     kube-apiserver-pytest-kind-control-plane
kube-system     kube-controller-manager-pytest-kind-control-plane
kube-system     kube-proxy-wb4hm
kube-system     kube-scheduler-pytest-kind-control-plane
local-path-storage      local-path-provisioner-6f8956fb48-ccsgm

Anything else?

No response

[jacobtomlinson]

I expect the root cause of dask/dask-kubernetes#851 is the same as this.

[jacobtomlinson]

Closed by #424