1. The problem I’m having:
I’m trying to reverse proxy an API with Caddy. The API is running in a docker container, Caddy is not. When I call localhost:1339/eval on the same machine (outside the container) it works as expected, even when I expose the port in my server’s firewall, I am able to call it from another machine. The issue is that Caddy can’t find it when I use reverse_proxy * localhost:1339/eval which gives me a 502 when I try to call it from another machine
2. Error messages and/or full log output:
{"level":"error","ts":1689662014.7019417,"logger":"http.log.error","msg":"dial localhost:1339: unknown network localhost:1339","request":{"remote_ip":"my ip address is here","remote_port":"65204","proto":"HTTP/1.1","method":"POST","host":"eval.occluder.space","uri":"/","headers":{"Authorization":[],"User-Agent":["PostmanRuntime/7.32.3"],"Accept":["*/*"],"Connection":["keep-alive"],"Content-Type":["text/plain"],"Postman-Token":["02711f75-6074-4ae2-9297-f3d48057d143"],"Accept-Encoding":["gzip, deflate, br"],"Content-Length":["19"]},"tls":{"resumed":false,"version":772,"cipher_suite":4865,"proto":"","server_name":"eval.occluder.space"}},"duration":1.273239821,"status":502,"err_id":"k4x3vt1hx","err_trace":"reverseproxy.statusError (reverseproxy.go:1299)"}
3. Caddy version:
v2.6.4
4. How I installed and ran Caddy:
I followed this line by line.
a. System environment:
Ubuntu 20.04
Architecture: x86_64
b. Command:
For reference, this is what I’m hosting: GitHub - discord-csharp/CSharpRepl: CSharpRepl is a web api for C# REPL using the Roslyn Scripting APIs
docker run -d --user www-data --restart=always --read-only --tmpfs /tmp --tmpfs /var --memory 500M --cpus 2 -p 1339:1339-e ASPNETCORE_URLS=http://+:1339 ghcr.io/discord-csharp/csharprepl:latest
docker ps
curl -X POST -H 'Content-Type: text/plain' -d 'var c = "xD -> c"; c' localhost:1339/eval
> {"returnValue":"xD -> c","returnTypeName":"string","exception":null,"exceptionType":null,"code":"var c = \"xD -> c\"; c","consoleOut":"","executionTime":"00:00:00.0514555","compileTime":"00:00:00.5248816"}
c. Service/unit/compose file:
see command above
d. My complete Caddy config:
eval.occluder.space {
file_server
basicauth * {
// auth
}
reverse_proxy * localhost:1339/eval
}
I have few other reverse proxy’d APIs running in the same way (not with docker, however), and they work fine