How to edit a file in a docker image before executing it?

Question

Angular

Good day.
Task: edit the configuration file (replace with sed) before starting the container.
The bottom line: there is a docker image, which is an assembled angular application with a specific base-href. Image is universal and rolls out in a compartment with others using docker-compose, combining several UIs and a bunch of microservices for backing. Since the rollout takes place at different sites, it became necessary to roll it out with a different base-href from the options to simply rebuild the container for the site, but since this is not according to the canon, we decided to change the base-href in index.html before launching. That’s all, but I didn’t find anything except command for these purposes and the code began to look terrible

ui-app1:
    image: harbor.example.local/project/gui/ui-app1:1.0.3
    ports:
      - "8981:80"
    network_mode: "bridge"
    command: >
      sh -c "sed -i -E 's|/test/|/public/test/|' /usr/share/nginx/html/ui-app1/index.html &&
      nginx -g 'daemon off;'"
    volumes:
      - type: bind
        source: ./ui-app1/default-area1.conf
        target: /etc/nginx/conf.d/default.conf
    depends_on:
      - haproxy

Hence the question, is there another, more beautiful solution?
While I was writing, the idea of ​​building a new image based on the current one came to mind (I just copy the contents of /usr/share/nginx/html/ and then edit index.html... but also the same %)

Answer 1

Well, it's really terrible, it's terrible when there are five lines of commands in the command.
In general, if the image is yours, then make a variable to make changes in it. If the image is not yours, then only with commands, you can still mount the script and execute it with the command.