502 for OPTIONS in Traefik 1.7-CodePudding

I'm testing a local Icecast server on Ubuntu, using Traefik 1.7 in Docker containers.

When manually going to a page on a subdomain, all CORS headers are set:

But accessing the page from another local domain always gives 502 errors on OPTIONS.

I've managed to get some debug info from the Traefik container, but I'm stuck as to how to solve this.

everse-proxy    | time="2022-11-11T21:08:01Z" level=debug msg="vulcand/oxy/forward/http: begin ServeHttp on request" Request="{\"Method\":\"OPTIONS\",\"URL\":{\"Scheme\":\"http\",\"Opaque\":\"\",\"User\":null,\"Host\":\"10.10.1.8:8000\",\"Path\":\"\",\"RawPath\":\"\",\"ForceQuery\":false,\"RawQuery\":\"\",\"Fragment\":\"\",\"RawFragment\":\"\"},\"Proto\":\"HTTP/2.0\",\"ProtoMajor\":2,\"ProtoMinor\":0,\"Header\":{\"Accept\":[\"*/*\"],\"Accept-Encoding\":[\"gzip, deflate, br\"],\"Accept-Language\":[\"en-US,en;q=0.9,nl;q=0.8\"],\"Access-Control-Request-Headers\":[\"icy-metadata\"],\"Access-Control-Request-Method\":[\"GET\"],\"Cache-Control\":[\"no-cache\"],\"Origin\":[\"https://gsr.localhost.traefik.me\"],\"Pragma\":[\"no-cache\"],\"Referer\":[\"https://gsr.localhost.traefik.me/\"],\"Sec-Fetch-Dest\":[\"empty\"],\"Sec-Fetch-Mode\":[\"cors\"],\"Sec-Fetch-Site\":[\"same-site\"],\"User-Agent\":[\"Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/107.0.0.0 Safari/537.36\"]},\"ContentLength\":0,\"TransferEncoding\":null,\"Host\":\"radio.localhost.traefik.me\",\"Form\":null,\"PostForm\":null,\"MultipartForm\":null,\"Trailer\":null,\"RemoteAddr\":\"127.0.0.1:53784\",\"RequestURI\":\"/radio\",\"TLS\":null}"
reverse-proxy    | time="2022-11-11T21:08:01Z" level=debug msg="Upstream ResponseWriter of type *pipelining.writerWithoutCloseNotify does not implement http.CloseNotifier. Returning dummy channel."
reverse-proxy    | time="2022-11-11T21:08:01Z" level=debug msg="'502 Bad Gateway' caused by: EOF"
reverse-proxy    | time="2022-11-11T21:08:01Z" level=debug msg="vulcand/oxy/forward/http: Round trip: http://10.10.1.8:8000, code: 502, Length: 11, duration: 5.960359ms tls:version: 303, tls:resume:true, tls:csuite:c02f, tls:server:radio.localhost.traefik.me"

The docker-compose.yml:

version: "3.1"

networks:
  db_default:
    external: true

services:
  reverse-proxy:
    container_name: reverse-proxy
    image: traefik:v1.7-alpine # The official Traefik docker image
    network_mode: "host"
    command: --api  --docker # Enables the web UI and tells Tr  fik to listen to docker
    volumes:
      - ./docker:/certs:ro
      - ./docker/traefik.toml:/etc/traefik/traefik.toml
      - /var/run/docker.sock:/var/run/docker.sock # So that Traefik can listen to the Docker events

  gsr2:
      container_name: gsrdev2
      build: docker
      volumes:
        - .bash_history:/root/.bash_history
        - ./:/var/www
        - ./log:/tmp/audit
      environment:
        #PHP_IDE_CONFIG: "serverName=gsr2.localhost.xip.io"
        XDEBUG_CONFIG: "start_with_request=yes"
      labels:
        - traefik.enable=true
        - "traefik.frontend.rule=Host:gsr.localhost.traefik.me"
      networks:
        - db_default

  icecast2:
    image: pltnk/icecast2
    container_name: icecast2
    expose:
      - 8000
    volumes:
      - ./icecast.xml:/etc/icecast2/icecast.xml
      - ./log:/var/log/icecast2
      - ./docker/bundle.pem:/etc/icecast2/bundle.pem
    labels:
      - traefik.enable=true
      - "traefik.frontend.rule=Host:radio.localhost.traefik.me"
    networks:
      - db_default

The traefik.toml:


defaultEntryPoints = ["http","https"]

loglevel="DEBUG"

[api]
    dashboard = false

[entryPoints]

[entryPoints.http]
    address = ":80"
#[entryPoints.http.redirect]
#    regex = "^http://(www.)*(.*)"
#    replacement = "https://$2"
#    permanent = true

[entryPoints.https]
    address = ":443"
    [entryPoints.https.tls]
       [[entryPoints.https.tls.certificates]]
           certFile = "/certs/cert.pem"
           keyFile = "/certs/key.pem"

[docker]
endpoint = "unix:///var/run/docker.sock"
domain = "localhost.traefik.me"
watch = true
exposedbydefault = false
network = "proxy"

Header config in Icecast server:

    <http-headers>
        <header name="Access-Control-Allow-Origin" value="*" />
        <header name="Vary" value="Origin" />
        <header name="Access-Control-Allow-Methods" value="GET, OPTIONS, PUT, POST" />
        <header name="Access-Control-Allow-Headers" value="Content-Type, Icy-Metadata" />
        <header name="Access-Control-Expose-Headers" value="Icy-MetaInt, Icy-Br, Icy-Description, Icy-Genre, Icy-Name, Ice-Audio-Info, Icy-Url, Icy-Sr, Icy-Vbr, Icy-Pub" />

    </http-headers>

CodePudding user response：

Generally, 502 Bad Gateway server error response code indicates that the server, while acting as a gateway or proxy, received an invalid response from the upstream server.

I don't see your Dockerfile but the error should be caused by:

missing network specifciation. You have to specify the network in your docker file to allow containers to connect
missing port. Add the traefik port traefik.port=80

CodePudding user response：

I fixed it! First I migrated to Traefik 2. Then, according to the Traefik docs, I can just include some middleware to set the headers for CORS directly on my container, like this:

  icecast2:
    image: pltnk/icecast2
    container_name: icecast2
    expose:
      - 8000
    volumes:
      - ./icecast.xml:/etc/icecast2/icecast.xml
      - ./log:/var/log/icecast2
    labels:
      - "traefik.http.middlewares.testheader.headers.accesscontrolallowmethods=GET,OPTIONS,PUT"
      - "traefik.http.middlewares.testheader.headers.accesscontrolalloworiginlist=*"
      - "traefik.http.middlewares.testheader.headers.accessControlAllowHeaders=Content-Type, Icy-Metadata"
      - "traefik.http.middlewares.testheader.headers.accesscontrolmaxage=100"
      - "traefik.http.middlewares.testheader.headers.addvaryheader=true"
      - traefik.enable=true
      - traefik.http.routers.icecast2.middlewares=testheader
      - "traefik.http.routers.icecast2.entrypoints=http,https"
      - "traefik.http.routers.icecast2.tls=true"
      - traefik.http.routers.icecast2.rule=Host(`radio.localhost.traefik.me`)