Possible to pass "slug" as env variable?

[ndeet]

I used your workflow from docker-bitcoind as a boilerplate for docker-electrumx and try to make it work (btw, thank you!):
https://github.com/lncm/docker-bitcoind/blob/1f0e20a93bc48faa5ebedc17991c231162112a50/.github/workflows/on-tag.yml#L155

the slug here is hardcoded and I see why, it is because the SLUG env var removes the "docker-" part from the repo for docker hub - but also the existing env var SLUG is not used here for some reason. I tried a few things to avoid hardcoding and pass ${SLUG} or similar to it but did not work. Is there any syntax how this could work or is this just not possible?

[meeDamian]

So, you need to be able to dynamically determine the value of SLUG during the build run?

[ndeet]

Not really dynamically per build run (each arch) but it would be nice to reuse the existing SLUG env variable and not hardcode it (in above case SLUG has already docker- removed therefore it would be nice to reuse it?.

E.g. as workflows do not work on forked repos (secrets not picked up so upload to docker hub fails) I now created a copy of lukechilds/docker-electrumx on my end ndeet/docker-electrumx-workflow so I can make sure the builds work before doing a PR on the upstream repo.

Like written the other issue, is there any debugging tool for workflows to test without actually running it?