Use different hostname / url than localhost for docker-compose web application - docker

Question

Summary: 2 separate applications, both using docker-compose, how can I have http://app-1.test and http://app-2.test available at the same time?
Description:
I feel like I've missed something super-simple. I have 2 php-fpm (via nginx) applications, both run by similar docker-compose setups, somewhat like:
# docker-compose.yaml
version: '3'
services:
app:
build:
context: .
dockerfile: docker/Dockerfile
container_name: app_1
tty: true
depends_on:
- db
- dbtest
working_dir: /var/www
volumes:
- ./:/var/www
webserver:
image: nginx:stable
container_name: app_1_webserver
restart: always
ports:
- "80:80"
depends_on:
- app
volumes:
- ./:/var/www
- ./docker/app.conf:/etc/nginx/conf.d/default.conf
links:
- app
# ...
On my /etc/hosts, I can add something like
127.0.0.1 app-1.test
Now I can call the app via the browser by going to app-1.test.
The second one has a similar setup, but of course it won't go up, because port 80 is blocked. I can of course change the port, but then the url would be something like app-2.test:81 instead of app-2.test. What can I do, so I can run a second application under a different local hostname? Or is using a different port the best way to go?

Answer 1

You can't. What you can do is add a "router" in front of your images (a third image) which does routing (proxy passing) based on the host name.
Apache or Nginx are often used for these kinds of things.
e.g. with apache server
https://httpd.apache.org/docs/2.4/howto/reverse_proxy.html
<VirtualHost *:80>
ServerName app-1.test
ProxyRequests Off
ProxyPreserveHost On
ProxyPass / http://image1:80/
ProxyPassReverse / http://image1:80/
ErrorLog /var/log/apache2/error.log
LogLevel info
CustomLog /var/log/apache2/access.log combined
</VirtualHost>
<VirtualHost *:80>
ServerName app-2.test
ProxyRequests Off
ProxyPreserveHost On
ProxyPass / http://image2:80/
ProxyPassReverse / http://image2:80/
ErrorLog /var/log/apache2/error.log
LogLevel info
CustomLog /var/log/apache2/access.log combined
</VirtualHost>
now you can add both names on the same ip in your /etc/hosts file and the server can route internally based on the provided hostname (ServerName).
The http://image1:80/ (and its like) references should be changed to the docker internal dns like specified in the docker-compose.yml