FastAPI integration ROOT_PATH problem

[sector119]

How do you use Sentry?

Sentry Saas (sentry.io)

Version

1.12.0

Steps to Reproduce

I have FastAPI app with nginx as proxy with following config. I host my api service on "/api/xmlrpc/v1" location and I rewrite it to send to my app on "/" location.

location /api/xmlrpc/v1 {
    proxy_set_header Host $http_host;
    proxy_set_header X-Real-IP $remote_addr;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header X-Forwarded-Port $server_port;
    proxy_set_header X-Forwarded-Proto $scheme;

    proxy_pass http://xmlrpc_api_service_upstream;
    rewrite ^/api/xmlrpc/v1/(.*)$ /$1 break;
}

To get FastAPI docs to work I must set FastAPI root_path argument to "/api/xmlrpc/v1" when I create app.

Here is request scope example
{'type': 'http', 'scheme': 'https', **'root_path': '/api/xmlrpc/v1'**, **'path': '/api/xmlrpc/v1'**}

Expected Result

What can I do to get url tag and curl example urls look as expected (https://api.my.site/api/xmlrpc/v1) ?

Actual Result

I get url tag like https://api.my.site/api/xmlrpc/v1/api/xmlrpc/v1 not https://api.my.site/api/xmlrpc/v1 as it has to be, as well as curl example.

That's happened because of asgi.py integration's _get_url() function where url path is
scope.get("root_path", "") + scope.get("path", "") that is why it got duplicated.

I can workaround it by setting FastAPI root_path=None and openapi_url='/api/xmlrpc/v1/openapi.json' and don't rewrite location for '/api/xmlrpc/v1/openapi.json' location while sending request to app from nginx, but it looks like a dirty hack.

Thank You

[smeubank]

I understand then that the problem is nginx is kindof duplicating the api route, and you're wondering if we have a better work around to get the original FastAPI route?

[sector119]

I understand then that the problem is nginx is kindof duplicating the api route, and you're wondering if we have a better work around to get the original FastAPI route?

Nginx doesn't duplicate it just rewrite url from "/api/xmlrpc/v1" to "/" while proxying request to upstream backend, but backend also get original url "/api/xmlrpc/v1" at scope["path"], but also FastAPI makes me set root_path to that original url "/api/xmlrpc/v1" to serve it's docs properly. And here we get duplicated path.

It's not a problem with nginx, but with asgi integration and _get_url() function IMO. It shouldn't concat root_path and path, or we have to redefine it by subclassing, I don't know..

So I don't wondering about a workaround. I think that I have to have a choice to prepend root_path to original path or not, because my backend app may or may not use root_path to generate route url. Right now it doesn't, only FastAPI use it to generate path to openapi.json correctly

[github-actions]

This issue has gone three weeks without activity. In another week, I will close it.

But! If you comment or otherwise update it, I will reset the clock, and if you label it Status: Backlog or Status: In Progress, I will leave it alone ... forever!

---

"A weed is but an unloved flower." ― Ella Wheeler Wilcox 🥀

[antonpirker]

Hey @sector119

Now I get it. We need to support the FastAPI option root_path properly.
Note so self: Look here: https://fastapi.tiangolo.com/advanced/behind-a-proxy/?h=root_path

[sector119]

Hey @sector119

Now I get it. We need to support the FastAPI option root_path properly. Note so self: Look here: https://fastapi.tiangolo.com/advanced/behind-a-proxy/?h=root_path

Yes, for sure !