How does a name get proxied to a port number?

[dit4c]

How does a name get proxied to a port number?

[tjdett]

Docker API does produce enough information (barely) to do this conversion. A few things worthy of note:

• Listing exposed ports is not exactly a clear part of the API, and appears inconsistent for container listings (as opposed to individual container JSON).
• While docker-java does exist, it uses Jackson to map JSON to fields in a way that doesn't handle API changes well. It's also synchronous, but that's probably not as big a deal because looking up this info on the fly probably isn't a good idea.
• All the names are prefixed with "/" for some reason. Also, the API allows multiple names, even though neither the CLI or API allow you to set multiple names.
• Docker container names are case sensitive, but domain name labels are not. All valid domain name labels seem to be valid docker container names though, which is good news. Domain name labels have a maximum length of 63 ASCII characters, which Docker is fine with.

[tjdett]

Work on this now forms dit4c/dit4c-gatehouse#1.

[tjdett]

Works fine with gatehouse and this nginx config fragment:

server {
  listen       localhost:80;
  server_name  localhost;
  root         /usr/share/nginx/html;

  location / {
    auth_request /auth;
    auth_request_set $upstreamport $upstream_http_x_upstream_port;
    proxy_pass http://127.0.0.1:$upstreamport;
    error_page 403 =204 /forbidden;
  }

  location /auth {
    internal;
    proxy_pass http://127.0.0.1:8080/auth;
    proxy_pass_request_body off;
    proxy_set_header Host $host;
    proxy_set_header Content-Length "";
    proxy_set_header X-Original-URI $request_uri;
  }

  location /forbidden {
    internal;
    return 204;
  }
}