[Frontend] Support custom request_id from request by guoyuhong · Pull Request #9550 · vllm-project/vllm

guoyuhong · 2024-10-21T12:14:38Z

FILL IN THE PR DESCRIPTION HERE:

Currently, request_id is generated in function create_chat_completion, which cannot be controlled by high-level user.

In our scenario, we want to pass the custom request_id into create_chat_completion. Then, we can debug the end-to-end process using a unique request id.

This PR simply add a field request_id to ChatCompletionRequest with a default random_uuid() value. If the user passes a request_id to the request object, the backend will use it directly. Otherwise, the backend will generate one which is the same as current behavior.

Example w/o request_id:

Example w/ request_id:

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github-actions · 2024-10-21T12:14:52Z

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guoyuhong · 2024-10-21T14:00:50Z

The PR is ready for review.

cjackal · 2024-10-21T15:43:04Z

Request ID is usually passed to the header(X-Request-Id) for accessibility; otherwise model server admins should (parse and) log the response body, which is a huge burden. OpenAI also returns request id in response header, so how about supporting X-Request-Id header (on both request and response) instead?

guoyuhong · 2024-10-21T16:54:19Z

@cjackal I can get X-Request-Id from raw_request.headers["x-request-id"]. Does that means that if the X-Request-Id is set, we can set it to response.id?

vllm/entrypoints/openai/serving_chat.py

vllm/entrypoints/openai/protocol.py

DarkLight1337

Thanks for adding this!

cjackal · 2024-10-22T16:15:51Z

@cjackal I can get X-Request-Id from raw_request.headers["x-request-id"]. Does that means that if the X-Request-Id is set, we can set it to response.id?

I'd suggest to implement it. Like:

AS-IS(v0.6.3.post1): X-Request-Id in request header is not passed back to response header

$ curl -v -X POST http://localhost:8000/v1/chat/completions \
> -d '{"model":"meta-llama/Llama-3.2-1B-Instruct","messages":[{"role":"user","content":"Hi"}]}' \
> -H 'X-Request-Id: aaaa' \
> -H 'Content-Type: Application/json'
*   Trying 127.0.0.1:8000...
* TCP_NODELAY set
* Connected to localhost (127.0.0.1) port 8000 (#0)
> POST /v1/chat/completions HTTP/1.1
> Host: localhost:8000
> User-Agent: curl/7.68.0
> Accept: */*
> X-Request-Id: aaaa
> Content-Type: application/json
> Content-Length: 88
> 
* upload completely sent off: 88 out of 88 bytes
* Mark bundle as not supporting multiuse
< HTTP/1.1 200 OK
< date: Tue, 22 Oct 2024 15:58:16 GMT
< server: uvicorn
< content-length: 230
< content-type: application/json
...

TO-BE:

$ curl -v -X POST http://localhost:8000/v1/chat/completions \
> -d '{"model":"meta-llama/Llama-3.2-1B-Instruct","messages":[{"role":"user","content":"Hi"}]}' \
> -H 'X-Request-Id: aaaa' \
> -H 'Content-Type: Application/json'
*   Trying 127.0.0.1:8000...
* TCP_NODELAY set
* Connected to localhost (127.0.0.1) port 8000 (#0)
> POST /v1/chat/completions HTTP/1.1
> Host: localhost:8000
> User-Agent: curl/7.68.0
> Accept: */*
> X-Request-Id: aaaa
> Content-Type: application/json
> Content-Length: 88
> 
* upload completely sent off: 88 out of 88 bytes
* Mark bundle as not supporting multiuse
< HTTP/1.1 200 OK
< date: Tue, 22 Oct 2024 15:58:16 GMT
< server: uvicorn
< content-length: 230
< content-type: application/json
< x-request-id: aaa
...

This is kind of standard approach for server log correlation (production level server usually keep logging incoming/outgoing headers, so no additional cost to pay) and easy to implement (simple middleware on fastapi side).

Of course my feature request is completely orthogonal to this PR; request id in chat completion stream body is independent of the request id in the header.

DarkLight1337 · 2024-10-22T16:20:48Z

@cjackal I can get X-Request-Id from raw_request.headers["x-request-id"]. Does that means that if the X-Request-Id is set, we can set it to response.id?

I'd suggest to implement it. Like:

AS-IS(v0.6.3.post1): X-Request-Id in request header is not passed back to response header
$ curl -v -X POST http://localhost:8000/v1/chat/completions \
> -d '{"model":"meta-llama/Llama-3.2-1B-Instruct","messages":[{"role":"user","content":"Hi"}]}' \
> -H 'X-Request-Id: aaaa' \
> -H 'Content-Type: Application/json'
*   Trying 127.0.0.1:8000...
* TCP_NODELAY set
* Connected to localhost (127.0.0.1) port 8000 (#0)
> POST /v1/chat/completions HTTP/1.1
> Host: localhost:8000
> User-Agent: curl/7.68.0
> Accept: */*
> X-Request-Id: aaaa
> Content-Type: application/json
> Content-Length: 88
> 
* upload completely sent off: 88 out of 88 bytes
* Mark bundle as not supporting multiuse
< HTTP/1.1 200 OK
< date: Tue, 22 Oct 2024 15:58:16 GMT
< server: uvicorn
< content-length: 230
< content-type: application/json
...
TO-BE:
$ curl -v -X POST http://localhost:8000/v1/chat/completions \
> -d '{"model":"meta-llama/Llama-3.2-1B-Instruct","messages":[{"role":"user","content":"Hi"}]}' \
> -H 'X-Request-Id: aaaa' \
> -H 'Content-Type: Application/json'
*   Trying 127.0.0.1:8000...
* TCP_NODELAY set
* Connected to localhost (127.0.0.1) port 8000 (#0)
> POST /v1/chat/completions HTTP/1.1
> Host: localhost:8000
> User-Agent: curl/7.68.0
> Accept: */*
> X-Request-Id: aaaa
> Content-Type: application/json
> Content-Length: 88
> 
* upload completely sent off: 88 out of 88 bytes
* Mark bundle as not supporting multiuse
< HTTP/1.1 200 OK
< date: Tue, 22 Oct 2024 15:58:16 GMT
< server: uvicorn
< content-length: 230
< content-type: application/json
< x-request-id: aaa
...
This is kind of standard approach for server log correlation (production level server usually keep logging incoming/outgoing headers, so no additional cost to pay) and easy to implement (simple middleware on fastapi side).

Of course my feature request is completely orthogonal to this PR; request id in chat completion stream body is independent of the request id in the header.

Sorry I missed this earlier. Thanks for bringing this up, can you open a new issue for this specifically so we can have a more comprehensive discussion about this?

cjackal · 2024-10-22T16:29:31Z

Sorry I missed this earlier. Thanks for bringing this up, can you open a new issue for this specifically so we can have a more comprehensive discussion about this?

I should say sorry for getting off the PR and spamming notifications; issue and PR for request id header are on the way.

Co-authored-by: Yuhong Guo <yuhong.gyh@antgroup.com> Signed-off-by: Alvant <alvasian@yandex.ru>

Co-authored-by: Yuhong Guo <yuhong.gyh@antgroup.com> Signed-off-by: Erkin Sagiroglu <erkin@infra-aipipeline-1-at1-prox-prod-a.ipa.corp.telnyx.com>

Co-authored-by: Yuhong Guo <yuhong.gyh@antgroup.com> Signed-off-by: Amit Garg <mitgarg17495@gmail.com>

Co-authored-by: Yuhong Guo <yuhong.gyh@antgroup.com> Signed-off-by: qishuai <ferdinandzhong@gmail.com>

Co-authored-by: Yuhong Guo <yuhong.gyh@antgroup.com> Signed-off-by: Sumit Dubey <sumit.dubey2@ibm.com>

Co-authored-by: Yuhong Guo <yuhong.gyh@antgroup.com> Signed-off-by: LeiWang1999 <leiwang1999@outlook.com>

Since vllm-project#9550 and vllm-project#10968 we support client's supplying a custom request ID. The motivation for this is that it can be very helpful when you need to correlate vLLM logs with logs of a related service. Since the request ID is used ubiquitously across vLLM as a unique key, it obviously is problematic if we ever have multiple in-flight requests using the same client-provided request ID. We saw this happening recently when `vllm serve bench` started including a request ID and the request IDs from multiple concurrent instances caused collisions. See vllm-project#27723 We try to guard against request ID collisions currently in the frontend in OutputProcessor: ``` def add_request(...): if request_id in self.request_states: raise ValueError(f"Request id {request_id} already running.") ``` however, this is not always effective: 1) We can have abort race conditions where a request is no longer tracked by the frontend, but still not completed in the engine. See vllm-project#15326 for an attempt to fix this. 2) We can have async scheduling race conditions where a request ID is removed from the output processor and being scheduled while the older request with that ID is still being completed by the model runner. See vllm-project#29355 3) With P/D, a request will continue to be tracked by the prefill engine long after the prefill request has been completed in the frontend, while we wait for the decode side to fetch the KV blocks. See vllm-project#20139 Let's instead ensure we use a unique request ID internally, even when a client provides a custom request ID. We can do this simply by appending a short random suffix to any request ID provided by the frontend. A full 32 character random UUID would be overkill as a suffix, so how many random characters would be sufficient? 8 characters gives us 32 bits of entropy, or 16^8 possible prefixes. Using the collision probability approximation from https://preshing.com/20110504/hash-collision-probabilities: N = 16^8 and k is the number of generated suffixes, then the probability of collision is (k^2)/(2N), so If a client somehow caused vLLM to hold 10k requests that reuse the same client-provided ID, then there would be a 1.16% chance of collision: ``` >>> (k**2)/(2*N) 0.011641532182693481 ``` That seems (super good enough)[https://hownot2.com/products/hownot2-super-good-enough-t-shirt]. The key changes to support this are: 1. `InputProcessor.process_inputs()` - we add some randomness to the request ID just before creating an `EngineCoreRequest`, and store both the random "internal" request ID (as `request_id`) and the supplied "external" request ID (as `external_req_id`) in the `EngineCoreRequest`. 2. `RequestState.make_request_output()` - we ensure that `RequestOutput.request_id` continues to be the external request ID (for backwards compat) and add `internal_request_id`. 3. `OutputProcessor.abort_requests()` - we make `OutputProcessor` track a mapping from external request ID to internal request IDs, so `abort_requests()` can abort based on either ID. 4. `AsyncLLM` - we use `RequestOutputCollector` to track the internal request ID, so we can use the internal ID to abort an in-progress request. We also add an `internal` boolean flag to `abort()` so API users can abort based on either ID. 5. `ParentRequest` - in the case of parallel sampling, we need to track both the internal and external ID for the later creation of `RequestOutput` aggregating the child outputs. We need to ensure we track the external->internal request ID mapping because abort() will be supplied an external request ID. In the case where an external request ID maps to multiple running requests, we assume the caller requires all of those requests to be aborted. The caller can use EngineCoreRequest.request_id as the request ID if they want to be more specific. Signed-off-by: Mark McLoughlin <markmc@redhat.com>

Support input request_id

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guoyuhong added 2 commits October 21, 2024 20:18

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guoyuhong changed the title ~~Support custom request_id from request~~ [Frontend] Support custom request_id from request Oct 21, 2024

DarkLight1337 reviewed Oct 22, 2024

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guoyuhong added 2 commits October 22, 2024 23:30

Address comments

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DarkLight1337 approved these changes Oct 22, 2024

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DarkLight1337 enabled auto-merge (squash) October 22, 2024 16:01

github-actions bot added the ready ONLY add when PR is ready to merge/full CI is needed label Oct 22, 2024

DarkLight1337 merged commit 434984e into vllm-project:main Oct 22, 2024

cjackal mentioned this pull request Oct 22, 2024

[Feature]: support x-request-id header #9593

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guoyuhong deleted the input_request_id branch October 23, 2024 00:37

Alvant pushed a commit to compressa-ai/vllm that referenced this pull request Oct 26, 2024

[Frontend] Support custom request_id from request (vllm-project#9550)

08344af

Co-authored-by: Yuhong Guo <yuhong.gyh@antgroup.com> Signed-off-by: Alvant <alvasian@yandex.ru>

garg-amit pushed a commit to garg-amit/vllm that referenced this pull request Oct 28, 2024

[Frontend] Support custom request_id from request (vllm-project#9550)

d58ef84

Co-authored-by: Yuhong Guo <yuhong.gyh@antgroup.com> Signed-off-by: Amit Garg <mitgarg17495@gmail.com>

FerdinandZhong pushed a commit to FerdinandZhong/vllm that referenced this pull request Oct 29, 2024

[Frontend] Support custom request_id from request (vllm-project#9550)

8dff237

Co-authored-by: Yuhong Guo <yuhong.gyh@antgroup.com> Signed-off-by: qishuai <ferdinandzhong@gmail.com>

sumitd2 pushed a commit to sumitd2/vllm that referenced this pull request Nov 14, 2024

[Frontend] Support custom request_id from request (vllm-project#9550)

aaea32d

Co-authored-by: Yuhong Guo <yuhong.gyh@antgroup.com> Signed-off-by: Sumit Dubey <sumit.dubey2@ibm.com>

tjohnson31415 mentioned this pull request Nov 22, 2024

[Bug]: Duplicate request_id breaks the engine #10583

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LeiWang1999 pushed a commit to LeiWang1999/vllm-bitblas that referenced this pull request Mar 26, 2025

[Frontend] Support custom request_id from request (vllm-project#9550)

f94b2b5

Co-authored-by: Yuhong Guo <yuhong.gyh@antgroup.com> Signed-off-by: LeiWang1999 <leiwang1999@outlook.com>

markmc mentioned this pull request Nov 3, 2025

[Core] Add a random suffix to frontend-provided request IDs #27987

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markmc mentioned this pull request Nov 25, 2025

Add request-ids to TranscriptionRequest, TranslationRequest #29357

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guoyuhong commented Oct 21, 2024

PR Title and Classification

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Adding or changing kernels

Notes for Large Changes

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