One nginx config for multiple dockerized ShinyR apps under different locations - docker

Question

we're trying to host a bunch of dockerized shinyR applications on a server. Each shinyR app is provided via docker-compose under a specific port. Each app should be available under its own location, e.g. https://example.com/app1 and https://example.com/app2
Requests under location app1 shall be directed to http://localhost:.
This is an excerpt of the nginx config file we're using:
map $http_upgrade $connection_upgrade {
default upgrade;
'' close;
}
server {
listen 443 ssl http2;
listen [::]:443 ssl http2;
server_name example.com;
root /var/www/html;
location /app1 {
proxy_pass http://127.0.0.1:3040/;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection $connection_upgrade;
}
...
}
What I receive is the bare shinyR application which is good but the client requests the proper assets (various JS libraries, images, etc) under the wrong location (/ and not /app1/) as can be seen in my browsers dev console:
GET https://example.com/shiny-javascript-1.7.4/shiny.min.js net::ERR_ABORTED 404
I can request this asset via https://example.com/app1/shiny-javascript-1.7.4/shiny.min.js, so it's served properly somehow.
My first question is, whether this is rather a shinyR or an NGINX problem? My guess is that shiny is telling the browser to request the assets from a wrong location and that we should start digging there but since I'm neither an expert on shinyR nor nginx it's a bit hard to tell where to start debugging.
For the sake of completeness here's the compose file running the shinyR apps
version: '3'
services:
app1:
image: "registry.gitlab.com/dezim/somefoo/bar:latest"
container_name: "app1"
command: R -e "shiny::runApp(appDir='/home/app', port=3040, host='0.0.0.0')"
restart: unless-stopped
ports:
- '127.0.0.1:3040:3040'