SOLVED: caddy reverse proxy error 502 (can't find host) | Railway | Page 1

rain scarab Oct 4, 2023, 9:35 AM

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Hi,
I am trying to setup a caddy reverse proxy.

caddyfile

{
    admin off
    persist_config off
    auto_https off
    log {
        format console
    }
    servers {
        trusted_proxies static private_ranges
    }
}

:{$PORT} {
    log {
        format console
    }

    reverse_proxy {$FRONTEND_HOST}
    reverse_proxy {$BACKEND_HOST}
}

proxy env vars:

FRONTEND_HOST=http://dashboard.railway.internal:3000
BACKEND_HOST=http://api.railway.internal:3000

My main focus now is the API
the API is listening to :::3000 (this is working)

When I go to my domain /api
I get error 502

foggy lynxBOT Oct 4, 2023, 9:35 AM

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Project ID: 1aa4380a-1423-4392-a56a-2d49595fe43e

weak brookBOT Oct 4, 2023, 9:35 AM

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To help others find answers, you can mark your question as solved via Right click solution message -> Apps -> ✅ Mark Solution

rain scarab Oct 4, 2023, 9:36 AM

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1aa4380a-1423-4392-a56a-2d49595fe43e

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2023/10/04 09:34:05.748 ERROR http.log.error.log0 dial tcp [my ipv6]:3000: connect: connection refused

rain scarab Oct 4, 2023, 10:23 AM

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with Nginx i get this

2023/10/04 10:22:50 [emerg] 1#1: host not found in upstream "api.railway.internal" in /etc/nginx/nginx.conf:13

nginx: [emerg] host not found in upstream "api.railway.internal" in /etc/nginx/nginx.conf:13

next tiger Oct 4, 2023, 2:57 PM

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what type of app is the backend/api ?

rain scarab Oct 4, 2023, 3:37 PM

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It's expressjs (and react)
However, I managed to get it working with this caddy config:

{ # global options
    admin off # theres no need for the admin api in railway's environment
    persist_config off # storage isn't persistent anyway
    auto_https off # railway handles https for us, this would cause issues if left enabled
    log { # runtime logs
        format console # set runtime log format to console mode 
    }
    servers { # server options
        trusted_proxies static private_ranges # trust railway's proxy
    }
}

:{$PORT} { # site block, listens on the $PORT environment variable, automatically assigned by railway
    log { # access logs
        format console # set access log format to console mode
    }

    reverse_proxy {$FRONTEND_HOST} # proxy all requests for /* to the frontend, configure this variable in the service settings

    # Handle /api/* without stripping the prefix
    reverse_proxy /api/* {$BACKEND_HOST} # proxy all requests for /api/* to the backend, configure this variable in the service settings
}

With these env vars:

FRONTEND_HOST=dashboard:3000
BACKEND_HOST=api:3000

For other people with a similar issue ^

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SOLVED: caddy reverse proxy error 502 (can't find host)

next tiger Oct 4, 2023, 3:38 PM

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haha glad you could solve, now its closer to the original caddyfile i wrote

rain scarab Oct 4, 2023, 3:40 PM

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next tiger haha glad you could solve, now its closer to the original caddyfile i wrote

Yes, though I think the main issue were the ENV vars, as I tried countless caddyfile variations 😄
It wouldn't work with http(s):// and/or railway.internal in there

next tiger Oct 4, 2023, 3:41 PM

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it would have, you just left out the /api/* part

rain scarab Oct 4, 2023, 3:42 PM

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I tried redirecting all traffic to the api instead, which also only would work without railway.internal. Don't ask me why 😦

#SOLVED: caddy reverse proxy error 502 (can't find host)

For other people with a similar issue ^