Portainer docker + JS injection

default.conf

js_path "/etc/nginx/conf.d/";
js_import main from default.js;

server {
  listen 9443 default_server ssl http2;
  listen [::]:9443 default_server ssl http2;
  ssl_certificate /certs/cert.pem;
  ssl_certificate_key /certs/key.pem;
  set $target "http://172.17.0.1:9000";

  location / {
    proxy_pass $target;
    proxy_set_header X-Real-IP $remote_addr;
    proxy_set_header X-Forwarded-For $remote_addr;
    proxy_set_header Host $host;
  }

  location ~* \.(?:js)$ {
    proxy_pass $target;
    # tweak
    proxy_set_header Accept-Encoding "";
    js_body_filter main.inject_js;
    js_header_filter main.content_length_filter;
  }

  location /api/websocket {
    proxy_pass $target;
    proxy_http_version 1.1;
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection "Upgrade";
    proxy_set_header Host $host;
  }
}

default.js

function inject_js(r, data, flags) {
    const search = "(self.webpackChunkportainer";
    if (data && data.startsWith && data.startsWith(search)) {
        r.sendBuffer(data.replace(search, `
            document.head.insertAdjacentHTML("beforeend", "<style>div.sidebar > button {display: none;}</style>");
            ${search}`), flags);
    } else {
        r.sendBuffer(data, flags);
    }
}

function content_length_filter(r) {
    r.headersOut['Content-Length'] = '';
}

export default {inject_js, content_length_filter};

docker-compose.yml

version: "2.4"
services:
  portainer:
    image: portainer/portainer-ce:latest
    container_name: portainer-ce
    hostname: portainer-ce
    restart: always
    ports:
      - 9000:9000
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock
      - ${HOME}/data/portainer:/data

  nginx:
    image: nginx:latest
    container_name: portainer-nginx
    hostname: portainer-nginx
    restart: always
    stop_signal: SIGKILL
    ports:
      - 9443:9443
    volumes:
      - ./certs:/certs
      - ./default.conf:/etc/nginx/conf.d/default.conf
      - ./default.js:/etc/nginx/conf.d/default.js
    command: /bin/sh -c "sed -i '1iload_module /usr/lib/nginx/modules/ngx_http_js_module.so;\\n' /etc/nginx/nginx.conf && nginx -g 'daemon off;'"