litellm/litellm/passthrough
devin-ai-integration[bot] 47bba14336
fix(passthrough): parse Bedrock stream spend incrementally instead of buffering the whole response (#40724)
* fix(passthrough): parse Bedrock stream spend incrementally instead of buffering the whole response

Bedrock pass-through streaming kept every relayed chunk in memory until EOF and
then decoded, parsed and translated the whole stream again for spend logging.
Large or concurrent streams could exhaust proxy worker memory.

Sync and async passthrough wrappers now hand each chunk to a provider stream
collector as it is relayed. Bedrock decodes event-stream frames incrementally,
folds consecutive text deltas, and keeps only what stream_chunk_builder needs
for usage, tool calls and metadata. Text deltas are no longer retained in the
Bedrock and Anthropic stream decoders either. Providers without a collector
keep the previous raw-bytes behavior. Collector failures are isolated so spend
tracking can never interrupt the customer stream

Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>

* test(passthrough): assert the spend payload the collector builds instead of mock internals

Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>

* test(passthrough): type the Bedrock collector helpers by the collector protocol instead of asserting the class

Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>

---------

Co-authored-by: yassin <yassin@berri.ai>
Co-authored-by: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
2026-09-11 09:53:37 -07:00
..
__init__.py refactor(lint): apply every safe ruff autofix and zero 28 strict-rule budgets 2026-08-01 15:43:29 -07:00
main.py fix(passthrough): parse Bedrock stream spend incrementally instead of buffering the whole response (#40724) 2026-09-11 09:53:37 -07:00
README.md build(VLLM-Passthrough-with-loadbalancing-support-(enables-using-model-list-for-VLLM-/classify-endpoint)): Closes #11205 2025-05-31 09:00:04 -07:00
timeout_utils.py feat(lint): enforce Final on locals and freeze function parameters (LIT010, LIT011) 2026-08-04 12:54:39 -07:00
utils.py fix(aws): build every AWS endpoint and ARN from the region partition 2026-08-29 01:21:59 -07:00

This makes it easier to pass through requests to the LLM APIs.

E.g. Route to VLLM's /classify endpoint:

SDK (Basic)

import litellm


response = litellm.llm_passthrough_route(
    model="hosted_vllm/papluca/xlm-roberta-base-language-detection",
    method="POST",
    endpoint="classify",
    api_base="http://localhost:8090",
    api_key=None,
    json={
        "model": "swapped-for-litellm-model",
        "input": "Hello, world!",
    }
)

print(response)

SDK (Router)

import asyncio
from litellm import Router

router = Router(
    model_list=[
        {
            "model_name": "roberta-base-language-detection",
            "litellm_params": {
                "model": "hosted_vllm/papluca/xlm-roberta-base-language-detection",
                "api_base": "http://localhost:8090", 
            }
        }
    ]
)

request_data = {
    "model": "roberta-base-language-detection",
    "method": "POST",
    "endpoint": "classify",
    "api_base": "http://localhost:8090",
    "api_key": None,
    "json": {
        "model": "roberta-base-language-detection",
        "input": "Hello, world!",
    }
}

async def main():
    response = await router.allm_passthrough_route(**request_data)
    print(response)

if __name__ == "__main__":
    asyncio.run(main())

PROXY

  1. Setup config.yaml
model_list:
  - model_name: roberta-base-language-detection
    litellm_params:
      model: hosted_vllm/papluca/xlm-roberta-base-language-detection
      api_base: http://localhost:8090
  1. Run the proxy
litellm proxy --config config.yaml

# RUNNING on http://localhost:4000
  1. Use the proxy
curl -X POST http://localhost:4000/vllm/classify \
-H "Content-Type: application/json" \
-H "Authorization: Bearer <your-api-key>" \
-d '{"model": "roberta-base-language-detection", "input": "Hello, world!"}' \

How to add a provider for passthrough

See VLLMModelInfo for an example.

  1. Inherit from BaseModelInfo
from litellm.llms.base_llm.base_utils import BaseLLMModelInfo

class VLLMModelInfo(BaseLLMModelInfo):
    pass
  1. Register the provider in the ProviderConfigManager.get_provider_model_info
from litellm.utils import ProviderConfigManager
from litellm.types.utils import LlmProviders

provider_config = ProviderConfigManager.get_provider_model_info(
    model="my-test-model", provider=LlmProviders.VLLM
)

print(provider_config)