Exception type: UnexpectedResponseError
Message: Server returned unexpected status code: 502 (https://debusine.trinitydesktop.net/api/1.0/artifact/trinity-testing/27688/)

Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/debusine/tasks/_task.py", line 841, in _execute
    if not self.fetch_input(download_directory):
           ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3/dist-packages/debusine/tasks/autopkgtest.py", line 271, in fetch_input
    self._prepare_executor()
    ~~~~~~~~~~~~~~~~~~~~~~^^
  File "/usr/lib/python3/dist-packages/debusine/tasks/_task.py", line 968, in _prepare_executor
    self.executor.download_image()
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^
  File "/usr/lib/python3/dist-packages/debusine/tasks/executors/unshare.py", line 79, in download_image
    self._local_path = self._image_cache.download_image(self.system_image)
                       ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3/dist-packages/debusine/tasks/executors/images.py", line 150, in download_image
    self._download_image_artifact(artifact.id, filename, path)
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3/dist-packages/debusine/tasks/executors/images.py", line 120, in _download_image_artifact
    self.debusine_api.download_artifact_file(
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^
        artifact_id,
        ^^^^^^^^^^^^
    ...<2 lines>...
        workspace=self.workspace,
        ^^^^^^^^^^^^^^^^^^^^^^^^^
    )
    ^
  File "/usr/lib/python3/dist-packages/debusine/client/debusine.py", line 708, in download_artifact_file
    artifact = self.artifact_get(artifact_id, workspace=workspace)
  File "/usr/lib/python3/dist-packages/debusine/client/debusine.py", line 416, in artifact_get
    return self._debusine_http_client.get(path, ArtifactResponse)
           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3/dist-packages/debusine/client/debusine_http_client.py", line 41, in get
    return self._api_request("GET", self._api_url + path, expected_class)
           ~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3/dist-packages/debusine/client/debusine_http_client.py", line 319, in _api_request
    raise exceptions.UnexpectedResponseError(
    ...<2 lines>...
    )
debusine.client.exceptions.UnexpectedResponseError: Server returned unexpected status code: 502 (https://debusine.trinitydesktop.net/api/1.0/artifact/trinity-testing/27688/)