[Core] Don't do platform detection at import time

[russellb]

Running just vllm or vllm --version or something similar resulted
in several lines of log noise about platform detection. This is because
several places were triggering this to occur at import time by doing the
following:

from vllm.platforms import current_platform

Platform detection runs the first time the current_platform attribute is
requested, which includes this import. Importing vllm.platforms and delaying
the reference to current_platform until code actually needs it avoids running
it in cases where it was never needed.

I only changed the places that caused a problem in my environment when running
vllm, though I'd say importing it like this at the top of a module is an
anti-pattern in general.

Signed-off-by: Russell Bryant [email protected]

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[youkaichao]

LGTM, I also want to make the import lazy, but unfortunately we have lots of from vllm.platforms import current_platform in the top level, because people don't like the long vllm.platforms.current_platform. usage :(

[DarkLight1337]

Can you fix the failure in Helm Chart CI?

[russellb]

Can you fix the failure in Helm Chart CI?

thanks for pointing it out. I'll take a look.

[russellb]

LGTM, I also want to make the import lazy, but unfortunately we have lots of from vllm.platforms import current_platform in the top level, because people don't like the long vllm.platforms.current_platform. usage :(

Yeah ... it's not obvious that importing that way is a problem and it'll be hard to remember to look for it during code reviews. I was thinking about changing it to be a function instead of an attribute, then it could be imported this way without a problem. That was just a much bigger change and I wanted to fix this immediate impact to the CLI first.

[russellb]

Can you fix the failure in Helm Chart CI?

thanks for pointing it out. I'll take a look.

I think this was just a huggingface error. I'll get it to run again.