Docker Image for UI application, to be served by Nginx server

Dockerfile

FROM nginx:latest

# dist includes the built output - npm build
COPY dist /usr/share/nginx/html

# nginx*conf to copy all the nginx configuration files to image.
COPY nginx*conf /opt/app-name/

# copy app entrypoint shell script
COPY entrypoint.sh /opt/app-name/

# make entrypoint.sh executable
RUN ["chmod", "+x", "/opt/app-name/entrypoint.sh"]

# start the container with running the script
ENTRYPOINT ["/opt/sre-ui/entrypoint.sh"]

# expose a port from container where the nginx server is listening
EXPOSE 8080

entrypoint.sh

#!/bin/bash

# read environment information from environment variable APP_ENV, defaults to 'local'
ENV="${APP_ENV:local}"

# copy the respective nginx configuration file, as per the environment
if [ "${ENV}" = "local" ] ; then cp /opt/app-name/nginx-local.conf /etc/nginx/conf.d/app-name.conf ; else cp /opt/app-name/nginx-prod.conf /etc/nginx/conf.d/app-name.conf ; fi

# run nginx in foreground, and not as daemon, because container watches initial process and is in running state
# based on only that process, so if nginx runs in foreground the process won't exit and hence container will keep running.
exec nginx -g "daemon off;"

nginx-sample.conf

# this includes the configuration, which is specific to the app
# overall nginx configuration like worker_processes, worker_connections etc is provided as default 
# by nginx:latest docker image at /etc/nginx/nginx.conf
# override that as well, as per the need.

server {
    listen  8080;
    root    /usr/share/nginx/html/;
    index   index.html;
    
    # if app has base path then below location block is needed.
    # for angular2 onwards, app hase base-href - https://angular.io/guide/router#base-href
    
    location /base/path/for/app {
        alias /usr/share/nginx/html/;
        try_files $uri $uri/ /index.html;
    }
}