[CI] Disable non-lazy string operation on logging

[rkooo567]

Enable this config; https://docs.astral.sh/ruff/rules/#flake8-logging-log

Basically, if you use fstring, format string, string percentage ops, string concat ops, it is evaluated although logging level is not configured. This can affect the performance, and performance is extremely critical for vllm. There has been an accident like #4270 (comment) due to this issue (adding a simple debugging log adds 20% e2e throughput regression)

This fixes the issue by not allowing these ops.

---

PR Checklist (Click to Expand)

Thank you for your contribution to vLLM! Before submitting the pull request, please ensure the PR meets the following criteria. This helps vLLM maintain the code quality and improve the efficiency of the review process.

PR Title and Classification

Only specific types of PRs will be reviewed. The PR title is prefixed appropriately to indicate the type of change. Please use one of the following:

• [Bugfix] for bug fixes.
• [CI/Build] for build or continuous integration improvements.
• [Doc] for documentation fixes and improvements.
• [Model] for adding a new model or improving an existing model. Model name should appear in the title.
• [Frontend] For changes on the vLLM frontend (e.g., OpenAI API server, LLM class, etc.)
• [Kernel] for changes affecting CUDA kernels or other compute kernels.
• [Core] for changes in the core vLLM logic (e.g., LLMEngine, AsyncLLMEngine, Scheduler, etc.)
• [Hardware][Vendor] for hardware-specific changes. Vendor name should appear in the prefix (e.g., [Hardware][AMD]).
• [Misc] for PRs that do not fit the above categories. Please use this sparingly.

Note: If the PR spans more than one category, please include all relevant prefixes.

Code Quality

The PR need to meet the following code quality standards:

• We adhere to Google Python style guide and Google C++ style guide.
• Pass all linter checks. Please use format.sh to format your code.
• The code need to be well-documented to ensure future contributors can easily understand the code.
• Include sufficient tests to ensure the project to stay correct and robust. This includes both unit tests and integration tests.
• Please add documentation to docs/source/ if the PR modifies the user-facing behaviors of vLLM. It helps vLLM user understand and utilize the new features or changes.

Notes for Large Changes

Please keep the changes as concise as possible. For major architectural changes (>500 LOC excluding kernel/data/config/test), we would expect a GitHub issue (RFC) discussing the technical design and justification. Otherwise, we will tag it with rfc-required and might not go through the PR.

What to Expect for the Reviews

The goal of the vLLM team is to be a transparent reviewing machine. We would like to make the review process transparent and efficient and make sure no contributor feel confused or frustrated. However, the vLLM team is small, so we need to prioritize some PRs over others. Here is what you can expect from the review process:

• After the PR is submitted, the PR will be assigned to a reviewer. Every reviewer will pick up the PRs based on their expertise and availability.
• After the PR is assigned, the reviewer will provide status update every 2-3 days. If the PR is not reviewed within 7 days, please feel free to ping the reviewer or the vLLM team.
• After the review, the reviewer will put an action-required label on the PR if there are changes required. The contributor should address the comments and ping the reviewer to re-review the PR.
• Please respond to all comments within a reasonable time frame. If a comment isn't clear or you disagree with a suggestion, feel free to ask for clarification or discuss the suggestion.

Thank You

Finally, thank you for taking the time to read these guidelines and for your interest in contributing to vLLM. Your contributions make vLLM a great tool for everyone!

[rkooo567]

Hmm is there any way to apply a linter rule to specific files only in ruff? Maybe it is not needed across all the repo

[tdg5]

Hmm is there any way to apply a linter rule to specific files only in ruff? Maybe it is not needed across all the repo

@rkooo567 , I made a PR to your PR branch fixing all the other logger lint errors 😁 rkooo567#20

[njhill]

I like this change and agree with @tdg5 that we should just apply it across the board.

In practice it mainly only matters for debug logs since the other levels will typically be enabled anyhow, but still good to do everywhere.

[simon-mo]

Yes please apply it across the board!

[rkooo567]

Thanks @tdg5 I merged your PR into this branch!

[rkooo567]

@simon-mo how can I make him a co-contributor of the PR? I will also fix remaining issues and ping you

[simon-mo]

Thanks @tdg5, upon merge the coauthor field should be updated.

[tdg5]

Weird, I'm not sure why, but my local bash format.sh missed a bunch of logger lint that CI caught. I will make another PR to fix the other ones tomorrow if no one beats me to it.

[rkooo567]

@tdg5 it is because ./format.sh only selects files that are modified in the PR! I will wait for your PR for tmrw then! Thank you so much for contribution again to the PR!

[tdg5]

Thanks @rkooo567! Second PR is here: rkooo567#21

[rkooo567]

@simon-mo do you know why this has merge conflict? It seems like I don't have it when I merge main in the local env

[tdg5]

@rkooo567 I saw the merge conflict earlier, which didn't really seem like an unmergable conflict, but now the UI doesn't show a merge issue needing to be resolved, so maybe just UI weirdness?

[rkooo567]

oh that's right. it is gone after I refreshed..

[rkooo567]

I will fix the test failure tmrw

[tdg5]

@rkooo567 , what test failure are you seeing? I tried looking at the buildkite failures but all I saw were indications that the test suites had been terminated by signals. There's a lot of output, so I probably missed an actual failure.

[rkooo567]

oh yeah. it might be just infra issue.

[tdg5]

@rkooo567 branch conflict resolution here: rkooo567#22