connect-to-localhost-services-from-containers-for-local-app-development.md

Add following to frappe container from the .devcontainer/docker-compose.yml:

...
  frappe:
    ...
    extra_hosts:
      app1.localhost: 172.17.0.1
      app2.localhost: 172.17.0.1
...

This is makes the domain names app1.localhost and app2.localhost connect to docker host and connect to services running on localhost.