fix(backend): Handle missing content in streaming delta #316
+1
−1
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
sjmonson
previously approved these changes
Sep 11, 2025
git-jxj
force-pushed
the
fix/streaming-keyerror-content
branch
from
55d32b0 to
697ea5e
Compare
Signed-off-by: xinjun.jiang <[email protected]>
git-jxj
force-pushed
the
fix/streaming-keyerror-content
branch
from
697ea5e to
6b0945c
Compare
sjmonson
approved these changes
Sep 12, 2025
tukwila
pushed a commit
to tukwila/guidellm
that referenced
this pull request
Sep 17, 2025
…#316) ## Summary This PR fixes a `KeyError: 'content'` that occurs when processing streaming chat completions. ## Details When using the `chat_completions` endpoint with `stream=True`, the final `delta` chunk sent by the server may not contain a `content` key. This is part of the standard API behavior to signal the end of the stream. The existing code in `_extract_completions_delta_content` did not account for this possibility and tried to access `delta['content']` directly, leading to a `KeyError` and causing the benchmark process to crash when the stream ended. ## Test Plan This was discovered while running `guidellm benchmark` against an OpenAI-compatible API endpoint (via `litellm`) that correctly implements the streaming protocol. guidellm benchmark \ --target "http://10.64.1.62:4000/v1" \ --model "qwen3-06b-2" \ --processor "Qwen/Qwen3-0.6B" \ --rate-type "synchronous" \ --max-requests 1 \ --data "prompt_tokens=32,output_tokens=32,samples=1" ## Related Issues vllm-project#315 - Resolves # --- - [x] "I certify that all code in this PR is my own, except as noted below." ## Use of AI - [ ] Includes AI-assisted code completion - [ ] Includes code generated by an AI application - [ ] Includes AI-generated tests (NOTE: AI written tests should have a docstring that includes `## WRITTEN BY AI ##`) Signed-off-by: xinjun.jiang <[email protected]> Co-authored-by: Samuel Monson <[email protected]>
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Summary
This PR fixes a
KeyError: 'content'that occurs when processing streaming chat completions.Details
When using the
chat_completionsendpoint withstream=True, the finaldeltachunk sent by the server may not contain acontentkey. This is part of the standard API behavior to signal the end of the stream.The existing code in
_extract_completions_delta_contentdid not account for this possibility and tried to accessdelta['content']directly, leading to aKeyErrorand causing the benchmark process to crash when the stream ended.Test Plan
This was discovered while running
guidellm benchmarkagainst an OpenAI-compatible API endpoint (vialitellm) that correctly implements the streaming protocol.guidellm benchmark
--target "http://10.64.1.62:4000/v1"
--model "qwen3-06b-2"
--processor "Qwen/Qwen3-0.6B"
--rate-type "synchronous"
--max-requests 1
--data "prompt_tokens=32,output_tokens=32,samples=1"
Related Issues
#315
Use of AI
## WRITTEN BY AI ##)