[Feature] Add argument to disable FastAPI docs

[mouweng]

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Motivation

This PR is to add a new argument option to disable the /, /openapi.json, /redoc and /docs/oauth2-redirect. My company doesn't allow using such endpoints in production environments. A new argument is added to disable the endpoint

reference doc: https://fastapi.tiangolo.com/tutorial/metadata/

Modification

Add argument --disable-fastapi-docs

BC-breaking (Optional)

N/A

Use cases (Optional)

lmdeploy serve api_server facebook/opt-125m --disable-fastapi-docs

• Before
  

• After
  

Checklist

1. Pre-commit or other linting tools are used to fix the potential lint issues.
2. The modification is covered by complete unit tests. If not, please add more unit tests to ensure the correctness.
3. If the modification has a dependency on downstream projects of a newer version, this PR should be tested with all supported versions of downstream projects.
4. The documentation has been modified accordingly, like docstring or example tutorials.

[AllentDan]

What is the purpose of using router?

[mouweng]

Because the original app = FastAPI(docs_url='/') was defined globally, I needed to control the availability of the documentation using the disable_fastapi_docs parameter passed into the serve function.

I moved the initialization of app = FastAPI(...) into the main function. The endpoints, such as '/v1/chat/completions', are registered through router, and finally, I use app.include_router(router) to included the router.

[AllentDan]

LGTM