Nginx static webpage and Docker with env variable url - docker

Question

I've got a nginx web server with a webpage inside that makes some http calls.
I want to dockerize all and use a parametric URL.
Is there a way to do this? Is it possible?

Answer 1

If I understood correctly you need a dynamic web page containing a script that makes HTTP calls to a configurable URL.
That can be achieved using Server Side Includes. with nginx. The webpage could include a configuration file that is created during the initialization of the container.
Create the file into the nginx document root when the image is first started. For example:
docker run -e URL=http://stackoverflow.com --entrypoint="/bin/sh" nginx -c 'echo ${URL} > /usr/share/nginx/html/url_config & exec nginx -g "daemon off;"'
For a real world scenario create a custom image based on nginx and override the entrypoint. The entrypoint creates the configuration file with the URL environment variable and eventually launches nginx in foreground.
Include the configuration file in the web page using the #include SSI directive
<script>
...
const http = new XMLHttpRequest();
const url = '<!--#include file="url_config" -->';
http.open("GET", url);
http.send();
...
Configure nginx to process SSI by adding the ssi on; directive
http {
ssi on;
...
}
Hope it helps.

Answer 2

Yes, it is possible,But you can do this using docker network if you want some routing. but you can do anything with Docker. According you question title you want to use ENV in URL in the Nginx Configuration. Here is the way to do that.
Set Environment in Docker run command or Dockerfile
Use that Environment variable in your Nginx config file
docker run --name nginx -e APP_HOST_NAME="myexample.com" -e APP_HOST_PORT="3000" yourimage_nginx
Now you can use these URL in your nginx configuration.
server {
set_by_lua $curr_server_name 'return os.getenv("APP_HOST_NAME")';
set_by_lua $curr_server_port 'return os.getenv("APP_HOST_PORT")';
proxy_pass http://$curr_server_name/index.html;
}
To deal with ENV with nginx you can check lua-nginx-module