Docker Reverse Proxy - apache

Question

I have a collection of web applications, with each running inside its own Docker Containers. I can access them locally via http://localhost:9001, for example. I want to access them remotely via https://site.example.com, instead. I have a wildcard Let's Encrypt certificate for example.com.
I understand I need Apache to do direct traffic from FQDN to Port. So I have setup a VirtualHost (below). Normal web activity seems to work fine. I can navigate the website normally.
However, when I try to login using OAuth (e.g. BitBucket), I get a URI redirect mismatch error. This does not happen when I run this outside of a container. I think there is something wrong with my Proxy setup. Is anyone able to advise how to rectify?
<VirtualHost *:443>
ServerAdmin admin#example.com
ServerName site.example.com
ServerSignature Off
ProxyRequests Off
ProxyPreserveHost On
ProxyPass / http://127.0.0.1:9001/
ProxyPassReverse / http://127.0.0.1:9001/
<IfModule mod_headers.c>
Header always set Strict-Transport-Security "max-age=15768000; includeSubDomains; preload"
</IfModule>
SSLEngine On
SSLCertificateFile /etc/letsencrypt/live/example.com/cert.pem
SSLCertificateKeyFile /etc/letsencrypt/live/example.com/privkey.pem
SSLCertificateChainFile /etc/letsencrypt/live/example.com/fullchain.pem
AllowEncodedSlashes NoDecode
</VirtualHost>

Answer 1

For such use case, Traefik is a very adapted tool. Coupled with docker-compose, you can setup multiple docker containers on the same host, each one having its own endpoint. To access them remotely, you just have then to bind remote host's IP address to all your endpoints (or use a public DNS that does it for you).
Here is a docker-compose.yml example using Traefik.
version: "3"
services:
traefik:
image: traefik:latest
command: --api --docker --logLevel=DEBUG
ports:
- "80:80"
- "443:443"
- "8082:8080"
volumes:
# So that Traefik can listen to the Docker events
- /var/run/docker.sock:/var/run/docker.sock
labels:
- "traefik.enable=false"
your_first_container:
image: <YOUR_IMAGE>
labels:
- "traefik.frontend.rule=Host:site.example.com"
- "traefik.port=9001"