nginx envsubst escape $

Dockerfile

FROM nginx:alpine

# https://thepracticalsysadmin.com/templated-nginx-configuration-with-bash-and-docker/
ENV LISTEN_PORT=80 \
  NGINX_ENV=production \
  SERVER_NAME=_ \
  RESOLVER=8.8.8.8 \
  UPSTREAM_API=api:3000 \
  UPSTREAM_API_PROTO=http \
  WORKDIR=/www \
  ESC='$'

WORKDIR ${WORKDIR}
COPY . .

COPY nginx.production.template /etc/nginx/nginx.production.template
COPY nginx.development.template /etc/nginx/nginx.development.template

EXPOSE ${LISTEN_PORT}
CMD /bin/sh -c "envsubst < ${WORKDIR}/nginx.${NGINX_ENV}.template > /etc/nginx/nginx.conf && nginx -g 'daemon off;' || cat /etc/nginx/nginx.conf"

gistfile1.txt

events {}

http {
  error_log stderr;
  access_log /dev/stdout;

  upstream upstream_api {
    server ${UPSTREAM_API};
  }

  upstream upstream_webpack {
    server ${UPSTREAM_WEBPACK};
  }

  server {
    listen ${LISTEN_PORT};
    server_name ${SERVER_NAME};
    resolver ${RESOLVER};

    # gzip configuration
    gzip on;
    gzip_disable "msie6";
    gzip_comp_level 6;
    gzip_min_length 1100;
    gzip_buffers 16 8k;
    gzip_proxied any;
    gzip_types
      # text/html is always compressed by HttpGzipModule
      text/css
      text/javascript
      text/xml
      text/plain
      text/x-component
      application/javascript
      application/json
      application/xml
      application/rss+xml
      font/truetype
      font/opentype
      application/vnd.ms-fontobject
      image/svg+xml;

    # Allow injecting extra configuration into the server block
    ${SERVER_EXTRA_CONF}

     # define the public application root
     root   ${WORKDIR}/public;
     index  index.html;

     # deny requests for files that should never be accessed
     location ~ /\. {
        deny all;
     }

     location ~* ^.+\.(rb|log)$ {
        deny all;
     }

     # send non-static file requests to the app server
     location ~* \/(_live|_ready|_before|_travel_to|_travel_back|graphql|validators|notifications) {
        try_files ${ESC}uri @api;
        expires -1;
        break;
     }

     # serve everything else via webpack
     location / {
        rewrite ^(.*)$ / break;
        try_files ${ESC}uri @webpack;
        expires -1;
     }

     location @api {
        proxy_set_header  X-Real-IP  ${ESC}remote_addr;
        proxy_set_header  X-Forwarded-For ${ESC}proxy_add_x_forwarded_for;
        proxy_set_header Host ${ESC}http_host;
        proxy_redirect off;
        proxy_pass ${UPSTREAM_API_PROTO}://upstream_api;
     }

     location @webpack {
        proxy_redirect off;
        proxy_pass ${UPSTREAM_WEBPACK_PROTO}://upstream_webpack;
     }
  }
}