Swagger UI PathPrefix patches for Traefik

docker-compose.yml

version: '3.3'
services:

  apidocs:
    image: swaggerapi/api-ui
    environment:
      API_URL: http://api.example.com/swagger.json
    ports:
      - 8080
    labels:
      traefik.enable: true
      traefik.port: 8080
      # match request paths without a trailing slash and redirect to the same
      # path, including the trailing slash. This prevents extrenal asset
      # inclusion issues for relative paths.
      # https://github.com/containous/traefik/issues/563#issuecomment-421360934
      traefik.frontend.rule: "Host:example.com;PathPrefix:/api;ReplacePathRegex:^/api/(.*) /$$1"
      traefik.frontend.redirect.regex: ^(.*)/api$$
      traefik.frontend.redirect.replacement: $$1/api/
      traefik.frontend.redirect.permanent: true