[Router] Support Batch API part 2

[gaocegege]

Ref #47

This PR introduces a new abstraction called BatchProcessor along with a default implementation, LocalBatchProcessor, which utilizes local synchronous tasks and SQLite to support batch APIs.

This PR works with this example https://github.com/vllm-project/production-stack/pull/109/files#diff-27b40f07027e82bfd7a96ae291892a045f6fcf3c1954ca8d357508b9b233066a. But currently, the core logic for handling batch requests to the backend inferences is not included https://github.com/vllm-project/production-stack/pull/109/files#diff-fcc40545eb2d5c49343a84bf1a2f326966017ed5651395c3f51092a459cbb755R180. I’ve identified the need for some refactoring of the HTTPXClientWrapper and the router to enable this during the implementation process.

I suggest merging this PR first, and then I will submit another to refactor the existing router.py to further implement the batch API. It will not affect the original behavior since there is a flag enable-batch-api to control.

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[ApostaC]

Thanks! We will take a look soon!
cc @YuhanLiu11 @Shaoting-Feng

[Shaoting-Feng]

Thanks for your contributions! Just left some comments.

[Shaoting-Feng]

Could you add more supports to run your example?

1. The change in helm charts: the deployment of router (to enable batch API) and the examples values.yaml
2. The Dockerfile to build router and install the new packages

[gaocegege]

Could you add more supports to run your example?

1. The change in helm charts: the deployment of router (to enable batch API) and the examples values.yaml
2. The Dockerfile to build router and install the new packages

Hi, I believe it's not the right time since the batch API isn't ready yet, and we haven't implemented the routing logic (https://github.com/vllm-project/production-stack/pull/109/files#diff-fcc40545eb2d5c49343a84bf1a2f326966017ed5651395c3f51092a459cbb755R179). I plan to address this in a future PR.

I suggest merging this PR first, and then I will submit another to refactor the existing router.py to further implement the batch API. It will not affect the original behavior since there is a flag enable-batch-api to control.

[gaocegege]

Please take a look, thanks for your time 😄

[ApostaC]

Hey @gaocegege , sorry I was pretty busy with some other stuff these days. Will take a look at this asap!

[Shaoting-Feng]

The changes in the router and the examples look good to me. Thanks for adding v1 to the @app.post in your latest commit.