Getting a unified docs endpoint for all mounted sub applications

[ollz272]

First Check

• I added a very descriptive title here.
• I used the GitHub search to find a similar question and didn't find it.
• I searched the FastAPI documentation, with the integrated search.
• I already searched in Google "How to X in FastAPI" and didn't find any information.
• I already read and followed all the tutorial in the docs and didn't find an answer.
• I already checked if it is not related to FastAPI but to Pydantic.
• I already checked if it is not related to FastAPI but to Swagger UI.
• I already checked if it is not related to FastAPI but to ReDoc.

Commit to Help

• I commit to help with one of those options 👆

Example Code

from fastapi import FastAPI

app = FastAPI()


@app.get("/app")
def read_main():
    return {"message": "Hello World from main app"}


subapi = FastAPI()


@subapi.get("/sub")
def read_sub():
    return {"message": "Hello World from sub API"}


app.mount("/subapi", subapi)

Description

What I want to be able to do is have the /docs endpoint on the main app include docs, with all the associated paths, of the subapplications.

So in the example above, /docs would include docs for both /app, and /subapi/sub

Operating System

macOS

Operating System Details

No response

FastAPI Version

103.1

Pydantic Version

2.4.1

Python Version

3.11.5

Additional Context

No response

[chrisK824]

I don't think this is possible based on the docs that declare that those are two fully independent fastapi applications there https://fastapi.tiangolo.com/advanced/sub-applications/?h=mount

That said, maybe you could try and "hack" this thing by messing around with the app instances and their attributes that form the docs with method openapi. I wouldn't recommend though even if possible.