nginx + docker: http to https redirection - docker

Question

I have an nginx inside a docker container which I want to force SSL on all request. Because I need to expose the webserver port in a different port outside the container, I'm not using standar ports when accesing the server.
I mapped the SSL port 443 inside my container to 8888 outside, so when I write the URL https://myserver:8888 the HTTPS works fine.
What happens when I don't use the https prefix? The port 443 is still listening but since I'm not using https schema I get the following error:
400 Bad Request
The plain HTTP request was sent to HTTPS port
If I redirect request to port 80 to 443 it is not enough, since because I'm accesign by the port 8888 the all requests are incoming by port 443, but I can not guarantee the schema used is HTTP.
I mean, the following block has not effect because I'm not exposing port 80 outside, only 8888 which maps direcly to 443
server {
server_name myserver;
listen 80;
return 301 https://$host:$server_port$request_uri;
}
How can I force it to work even when the user puts http on the URL?
Thank you

Answer 1

You have to use two different ports : for example 8888 and 8889.
Bind the first port to the container's 80, and the second to 443.
If a client want to contact your container on http it will have to use 8888 (-> 80). If the vhost is well configured nginx will serve a 301 or 302 HTTP return code (a redirect) to the https port (8889 -> 443).
So your return might look like
return 301 https://$host:8889$request_uri;
And the client will start a TLS connection on the right port.
Due to technical limitation it's pretty hard to use the same port for both clear traffic and TLS-encrypted one, so most of the webservers will listen on two distinct ports : 80 for plain-text and 443 for TLS.