Hi,

I have a single Dockerfile that I use in two different services, so to properly set the service_id in the cache mount (https://docs.railway.com/guides/dockerfiles#cache-mounts) , I went with the build time variables ARG RAILWAY_SERVICE_ID (https://docs.railway.com/guides/dockerfiles#using-variables-at-build-time).

That didn't work and I found that the $RAILWAY_SERVICE_ID variable cannot be used (https://station.railway.com/questions/is-the-cache-id-with-the-id-of-the-servi-a28aae85, https://station.railway.com/questions/docker-build-cache-issue-b2b13274) in the Dockerfile (some sort of exception I guess? Should be stated on the docs).

So, apart from hardcoding it (which I can't since I have 2 services using the same Dockerfile with different commands), what would be the best way to do it? Since apparently I can use user-defined-variables, couldn't I declare a variable USER_SERVICE_ID in each of the services with the value of $RAILWAY_SERVICE_ID and use $USER_SERVICE_ID in my Dockerfile? Sounds like a way to overcome that restriction, although I do not know the implications.

Thanks!