fix: FastAPI built-in paths bypass custom routing (Docs) and update r… (#1841)

## What does this PR do?

This PR improves the server's request routing logic by ensuring built-in
FastAPI paths such as `/docs`, `/redoc`, `/openapi.json`,
`/favicon.ico`, and `/static` bypass the custom `TracingMiddleware`.
This prevents unnecessary tracing logic for documentation and static
file requests, ensuring better performance and cleaner logs.

Additionally, it adds proper metadata (`title`, `description`, and
`version`) to the FastAPI application initialization and updates the
requirements document accordingly.

[//]: # (Closes #1822 )

---

## Test Plan

- Ran the server locally with `uvicorn` using the provided `run.yaml`
config
- Verified that:
- FastAPI docs (`/docs`, `/redoc`) load correctly without triggering the
custom tracing middleware
  - All other routes still go through the middleware and trace logic
  - Application metadata appears as expected in the OpenAPI docs

To reproduce:
1. Start the server with `python server.py --template <template-name>`
2. Navigate to `/docs` and `/redoc`
3. Confirm that no extra trace headers are added for those routes
4. Confirm other API endpoints behave as expected and include
`x-trace-id` in the response headers

[//]: # (## Documentation)

---

Froze the requirements file to include many of the other libraries that
have been added in the past few releases to make install easier.

---------

Co-authored-by: Sébastien Han <seb@redhat.com>
This commit is contained in:
Peter Double 2025-04-14 13:28:25 -04:00 committed by GitHub
parent cf158f2cb9
commit 86c6f1f112
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@ -229,15 +229,30 @@ class TracingMiddleware:
def __init__(self, app, impls):
self.app = app
self.impls = impls
# FastAPI built-in paths that should bypass custom routing
self.fastapi_paths = ("/docs", "/redoc", "/openapi.json", "/favicon.ico", "/static")
async def __call__(self, scope, receive, send):
if scope.get("type") == "lifespan":
return await self.app(scope, receive, send)
path = scope.get("path", "")
# Check if the path is a FastAPI built-in path
if path.startswith(self.fastapi_paths):
# Pass through to FastAPI's built-in handlers
logger.debug(f"Bypassing custom routing for FastAPI built-in path: {path}")
return await self.app(scope, receive, send)
if not hasattr(self, "endpoint_impls"):
self.endpoint_impls = initialize_endpoint_impls(self.impls)
_, _, trace_path = find_matching_endpoint(scope.get("method", "GET"), path, self.endpoint_impls)
try:
_, _, trace_path = find_matching_endpoint(scope.get("method", "GET"), path, self.endpoint_impls)
except ValueError:
# If no matching endpoint is found, pass through to FastAPI
logger.debug(f"No matching endpoint found for path: {path}, falling back to FastAPI")
return await self.app(scope, receive, send)
trace_context = await start_trace(trace_path, {"__location__": "server", "raw_path": path})
@ -388,7 +403,12 @@ def main(args: Optional[argparse.Namespace] = None):
safe_config = redact_sensitive_fields(config.model_dump())
logger.info(yaml.dump(safe_config, indent=2))
app = FastAPI(lifespan=lifespan)
app = FastAPI(
lifespan=lifespan,
docs_url="/docs",
redoc_url="/redoc",
openapi_url="/openapi.json",
)
if not os.environ.get("LLAMA_STACK_DISABLE_VERSION_CHECK"):
app.add_middleware(ClientVersionMiddleware)