[Misc] Separate prompt logging to debug

[aitsvet]

Purpose

Split the logger.info call in vllm/entrypoints/logger.py to differentiate between verbose prompt-related details and essential request parameters.

This change moves request_id, prompt, prompt_token_ids, and prompt_embeds to a new logger.debug call. The original logger.info now only contains params and lora_request. This improves log clarity by:

• Reducing log noise at the INFO level in production environments.
• Providing detailed prompt information only when debug logging is enabled.

Test Plan

1. Run existing unit and integration tests to ensure no regressions.
2. Enable debug logging and verify that prompt-related information (request_id, prompt, prompt_token_ids, prompt_embeds) is correctly logged at the DEBUG level.
3. With default info-level logging, verify that only params and lora_request are logged by the logger.info call.

Test Result

• The logger.info call in vllm/entrypoints/logger.py has been split.
• Prompt-related fields (request_id, prompt, prompt_token_ids, prompt_embeds) are now logged via logger.debug.
• Essential request parameters (params, lora_request) remain in the logger.info call.
• No functional changes or regressions are expected.

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[gemini-code-assist]

Code Review

This pull request improves logging by separating verbose prompt details into a DEBUG level log, which is a good change for reducing log noise in production. My review includes a suggestion to further improve log clarity by making the new DEBUG log message more distinct from the INFO message, avoiding redundancy.

[gemini-code-assist]

The log message prefix "Received request %s" is duplicated in both the DEBUG and INFO level logs. This is redundant and can make logs harder to read when debugging, as two lines for the same request will start with the same text. To improve log clarity, the DEBUG log message should be distinct to indicate it provides supplementary details for the request announced in the INFO log.

Suggested change

	logger.debug(
	"Received request %s: prompt: %r, "
	"params: %s, prompt_token_ids: %s, "
	"prompt_embeds shape: %s, "
	"lora_request: %s.",
	"prompt_token_ids: %s, "
	"prompt_embeds shape: %s.",
	request_id,
	prompt,
	params,
	prompt_token_ids,
	prompt_embeds.shape if prompt_embeds is not None else None,
	)
	logger.debug(
	"Request %s details: prompt: %r, "
	"prompt_token_ids: %s, "
	"prompt_embeds shape: %s.",
	request_id,
	prompt,
	prompt_token_ids,
	prompt_embeds.shape if prompt_embeds is not None else None,
	)

[aitsvet]

markmc commented

I think we should avoid a proliferation of magic environment variables like this

Unconditionally changing the default behaviour seems reasonable to me - basically, reducing the info level detail, and adding more detail at debug level

(Note for reviewers - this already requires --enable-log-requests, it's not on by default)

[Frontend] Add request arrival log #26685

[DarkLight1337]

Makes sense, thanks