Hello everyone! I am trying to deploy prefect orion server behind an nginx reverse proxy, at a different location than

/

, for instance

/prefect/

. I am having an issue with loading the UI when I access

<http://localhost/prefect/>

as the UI cannot load the corresponding assets, because it ignores the location prefix when doing the requests, for instance:

<http://localhost/assets/index.1a4d60fb.js>

is available at

<http://localhost/prefect/assets/index.1a4d60fb.js>

. Is there a way to specify a prefix or some sort of redirect URL for the UI to use when doing requests?

Have you tried setting

PREFECT_ORION_UI_API_URL

to

<http://localhost/prefect/api>

?

Yes, I did that, but the issue is with the static files which the Prefect UI is loading.

We have done something similar with Traefik in that past. The solution was to add a path-stripping middleware. I have never done this with NGINX, but maybe this helps? https://serverfault.com/a/562850

Thanks for the tip. I have tried that already and I have managed to load the UI, but whenever I am navigating to a new route in the UI, for instance to

/runs

, starting from

localhost/prefect/

I am redirected to l

localhost/runs

, instead of

localhost/prefect/runs

@Thomas Fredriksen I try to manage this in Traefik as well but can get it to setup. Can you point me into the direction to setup the middleware?

@Timo - We are using the External Auth Server (https://github.com/travisghansen/external-auth-server) as a middleware. Once set up, it is just a matter of specifying the middleware CRD:

apiVersion: <http://traefik.containo.us/v1alpha1|traefik.containo.us/v1alpha1>
kind: Middleware
metadata:
  name: eas-prefect
  namespace: prefect
spec:
  forwardAuth:
    address: >-
      <https://external-auth-server.myhost.com/verify?fallback_plugin=0&config_token=CONFIG_TOKEN>
    authResponseHeaders:
      - X-Forwarded-User
      - X-Forwarded-Uri
      - X-Userinfo
      - X-Id-Token
      - X-Access-Token
      - Authorization
    trustForwardHeader: true

@Thomas Fredriksen thanks for sharing this. I'll looking into that. This means that you don't use path-stripping middleware anymore, right?

You will need the path-stripping middleware if your path is not root. For example if you are hosting prefect at

<http://myhost.com/path/to/prefect|myhost.com/path/to/prefect>

, then you will need to apply path stripping to

/path/to/prefect

I receive the error in console for the static files. There is the

/prefect

path missing... But configured the middleware as traefik label as following:

labels:
      - "traefik.enable=true"
      - "traefik.http.routers.prefectserver.rule=(Host(`bla.bla`) && PathPrefix(`/prefect`))"
      - "traefik.http.middlewares.prefect-prefix.stripprefix.prefixes=/prefect"
      - "traefik.http.middlewares.prefect-prefix.stripprefix.forceSlash=false"
      - "traefik.http.routers.prefectserver.middlewares=prefect-prefix@docker"

@Timo I'm afraid I have not seen this issue before. Have you gotten it to work without the

/prefect

-path?

@Thomas Fredriksen thanks, for your response. Without the

/prefect

path it works like a charm. But if I add the prefix and the stripping it doesn't get added to the static files somehow...

@Timo The issue may be related to how the API-calls from the Web-UI are handled. One thing you could try is to set a rule based on the request referer. Something like

Host("<http://myhost.com|myhost.com>") && Headers("referer", "<http://myhost.com/prefect|myhost.com/prefect>")

@Thomas Fredriksen do you mean something like `- "traefik.http.routers.prefectserver.rule=Host(

<http://myhost.com|myhost.com>

) && Headers(

referer

,

<http://myhost.com/prefect|myhost.com/prefect>

)"` This ends up in a 404 😞

@Timo It could be worth trying with

origin

instead of

referer

. Also - is your

PREFECT_ORION_UI_API_URL

environment variable set correctly?

@Thomas Fredriksen this ends in a 404, too 😞 My

PREFECT_ORION_UI_API_URL

is set to "http://myhost.com/prefect". But even if I use "http://localhost/prefect/api" as suggested by you in another post it doesn't work. If I use the pathprefix I can connect through CLI the only problem is, that I can't load the assets in the browser....

Been looking at this same issue. The UI uses an environment variable called ORION_SERVE_BASE, but this has to be set a build time, as I see in the Dockerfile: https://github.com/PrefectHQ/prefect/blob/c5a14cef4ead7d6c7e550194d4bbb7f3b90f15f3/Dockerfile#L35 So I think you’d need to build the UI yourself with this environment variable set.

@Dylan McReynolds did you solve this issue? I tried to build the image on my own but didn't work sofar without modification bc ORION_SERVE_BASE is not a build arg. So further modifications are necessary. Even when setting ORION_SERVE_BASE this doesn't work for me...