Nginx HTTP not redirecting to HTTPS 400 Bad Request "The plain HTTP request was sent to HTTPS port"

Question

I'm running nginx in docker. HTTPS works fine but when I explicitly make HTTP request I get the following error

400 Bad Request The plain HTTP request was sent to HTTPS port

nginx.conf is as follows

worker_processes auto ;          
events {}

http {

include /etc/nginx/mime.types;

access_log /var/log/nginx/main.access.log;                                           

server {    
listen 80;                                                                                                       
location / {
    return 301 https://localhost:3000$request_uri; 
}

}

server {   
listen 443 ssl;                                                      
server_name  localhost:3000;                  
 root    /var/www/html; 

ssl_certificate         /etc/nginx/ssl/cert.pem; 
ssl_certificate_key     /etc/nginx/ssl/key.pem;

ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
ssl_prefer_server_ciphers on;
ssl_ciphers ECDH+AESGCM:ECDH+AES256:ECDH+AES128:DH+3DES:!ADH:!AECDH:!MD5;

location / {
try_files  $uri /index.html;        
}

}

}

I run this container using

docker run -p 3000:443 -it -d --name nginxtest nginx-test

and get the following error

docker file is as follows

FROM nginx:latest
COPY ./build /var/www/html
COPY ./nginx.conf /etc/nginx/nginx.conf
COPY ./ssl /etc/nginx/ssl
EXPOSE 443
CMD [ "nginx","-g","daemon off;" ]

Weird thing is that sometimes it works perfectly fine, and all of a sudden it stops working and won't even work if I recreate the containers.

Even tried doing the following. Still no luck

 server {    
    listen 80;                                                                                                       
     server_name localhost:3000
        return 301 https://localhost:3000$request_uri; 
    }

Another odd thing when I run the following docker command

docker run -p 3000:443 -p 3001:80 -it -d --name nginxtest nginx-test

and go to localhost:3001 it redirects me to https just fine but other things do break. Sorry for the long question

Answer 1

Put the following directive to the server block where you listen for port 443.

error_page 497 https://$host:$server_port$request_uri;

This directive implies that when "The plain HTTP request was sent to HTTPS port" happens, redirect it to https version of current hostname, port and URI.

Kinda hacky but works.

Answer 2

In my case the nginx server was on a different docker container than the application itself and slight change required to the @Yarimadam's answer so the uri can be resolved properly:

error_page 497 https://$http_host$request_uri;

So intead of variables $host:$server_port$ I used $http_host .