HOST bug or expected behavior?

[wataruian]

I've been following the experimental feature to add host in /etc/hosts for the duration of the build (HOST) and found something (bug or expected behavior?):

1. I can't seem to pass dynamic value to HOST, if I tried passing the ARG it really tries to add ${ARG_NAME} in /etc/hosts, I tried even setting as ENV, still the same. But hardcoding the value is working
2. SAVE IMAGE does not seem to respect what is in /etc/hosts. So I am unable to push to the local registry, which when you try to do curl in +success-access-host is successful.

VERSION --use-host-command 0.6

FROM alpine:3.14

ARG IP="192.168.1.9"
ARG DOMAIN="mylocalhost.com"

success-set-host:
  HOST mylocalhost.com 192.168.1.9

failed-set-host:
  RUN echo ${DOMAIN}
  RUN echo ${IP}
  HOST ${DOMAIN} ${IP}

success-access-host:
  HOST mylocalhost.com 192.168.1.9
  RUN apk update && apk add curl && curl -GET mylocalhost.com:5000/v2/_catalog

failed-push:
  HOST mylocalhost.com 192.168.1.9
  SAVE IMAGE --insecure --push mylocalhost.com:5000/some-image:1.0

Any , idea how to achieve this?

Thanks!

[dchw]

Right now, the HOST keyword only accepts static values. It seems reasonable to incorporate this.

Making HOST also be respected by SAVE IMAGE could be more tricky, and requires more thought, as it would require applying the HOST entry at the buildkit layer, not the currently-executing-build-command layer. This may be more difficult to achieve; or require a separate mechanism. One workaround that could work right now is to leverage our buildkit_additional_args config option. Something like this: earthly global.buildkit_additional_args ["--add-host", "yourdomain.com:127.0.0.1"] would allow buildkit to push to a custom hostname.

[vladaionescu]

For the expansion, it seems that we forgot to call expandArgs on these two: https://github.com/earthly/earthly/blob/main/earthfile2llb/interpreter.go#L1387-L1388. We welcome a contribution if you'd like to add that yourself.

[wataruian]

Looks like this is the one I am needing for the long time (did not even know this existed):
earthly global.buildkit_additional_args ["--add-host", "yourdomain.com:127.0.0.1"]

I am not sure if HOST interfering with buildkit hosts is a wanted/good thing though, if needed it can be easily done with (--add-host - Thanks @dchw).

But HOST being able to accept variables for DOMAIN and IP makes sense.