IKholopov opened a new pull request, #45759:
URL: https://github.com/apache/airflow/pull/45759
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Pod*Exceptions has been moved from core to providers back in
https://github.com/apache/airflow/commit/de92a81f002e6c1b3e74ad9d074438b65acb87b6,
but kept in `airflow/exceptions.py` under try-case for backwards compatibility
and allow for usage of an older k8s provider with a newer core airflow.
This resulted in 2 unintended side-effects:
1. Any CLI command started taking ~ 1s longer to start. That is because
importing anything from `airflow` resulted in importing `kubernetes` client. It
is effectively the most expensive import out of all CLI does for any command,
even though it is used by very few commands. Here are the timings of a trivial
`airflow dag-processor --help`
- Before this PR: 6.0s https://pastebin.com/zb0QHFq9
- After this PR: 4.97s https://pastebin.com/QC5Rbyt5
2. Some time ago the compatibility import broke altogether. Because of the
amount of imports in `pod_generator.py`, the import from `exceptions.py` failed
even if providers were up to date with recursive import. But it was caught by
exception handling, resulting in `from airflow.exceptions import
PodMutationHookException` and `from
airflow.providers.cncf.kubernetes.pod_generator import
PodMutationHookException` pointing to different classes defeating the purpose
of the fallback.
This PR addresses both by moving PodGenerator exceptions to the separate
module that only import its base class. This keeps imports backwards
compatible, doesn't attempt to load k8s modules and fixes the divergence of
exception classes in `airflow.providers.cncf.kubernetes.pod_generator` and
`airflow.exceptions`.
It is worth noting, that all usages of those exceptions in core Airflow also
has been cleaned up since then, so if you believe that we need to remove those
exceptions from `airflow/exceptions.py`, please let me know.
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