dev: Document example accepted docker image formats for action

[corneliusroemer]

Context
I wanted to test compatibility of ncov build actions with a new docker image (Snakemake 7.24.1).

When triggering through workflow_dispatch one can overwrite the image to be used.

It wasn't clear to me from the description what was accepted here. Would this be ok:

• nextstrain/base:branch-snakemake-7.24.1
  or would I have to add container registry URL, etc?

It would be great if there was an example tag that was explained or a link to docs where one can see what is accepted here.

The string to be changed is here (and similar for the other actions):

ncov/.github/workflows/rebuild-open.yml

Line 18 in cfa73be

description: 'Specific container image to use for build (will override the default of "nextstrain build")'

Maybe it would be enough to state that the default is nextstrain/base, a classic docker pull image descriptor: https://docs.nextstrain.org/projects/cli/en/stable/commands/build/#development-options

[tsibley]

It's any image descriptor accepted by Docker. This includes:

nextstrain/base
nextstrain/base:branch-snakemake-7.24.1
nextstrain/base@sha256:5efcfcbe3cdcaaed225007b45169ae59f8a154efbde0f720f662c81e1fa39c38
docker.io/nextstrain/base
docker.io/nextstrain/base:branch-snakemake-7.24.1
ghcr.io/another/image

[corneliusroemer]

Thanks @tsibley! This is maybe worth adding to the CLI docs (or not if it's too rarely used/verbose)