multi-stage dockerfile: This reduces image size to half compare to ea…

[StarTrooper08]

multi-stage dockerfile: This reduces image size to half compare to earlier image version size.

Before multi-stage build

After multi-stage build(r-multi-stage build -> r-dev-env image)

[hturner]

This looks okay to me, but I see ubuntu 22.04 is hard-coded. Maybe we can use ubuntu-latest to avoid needed to update later?

[StarTrooper08]

If we use just ubuntu instead of ubuntu:22, it will automatically used as latest.
Will make the following change and also have a look over build process.

[hturner]

If we use ubuntu latest, then we can also prefer r-universe over CRAN when installing R packages, so that we install from the linux binary rather than from source, i.e.

&& Rscript -e "install.packages(c('languageserver', 'httpgd'), \
repos = c(runiverse='https://r-universe.dev', CRAN='https://cloud.r-project.org'))" \

This should save quite a lot of time in the build.

[StarTrooper08]

Sure updating the file shortly.

[remlapmot]

(I was just randomly follow a few R dev related repos) Just to point out that URL for the r-universe cran linux binary repo doesn't look correct - as far as I know it is

https://cran.r-universe.dev/bin/linux/noble-x86_64/4.5/

which you can infer from https://docs.r-universe.dev/install/binaries.html

or by hovering your mouse over a Linux package on any package page under https://cran.r-universe.dev/ e.g. https://cran.r-universe.dev/MRAM

and httpgd (as regularly happens) currently isn't on CRAN so you can obtain that from it's developer's r-universe

&& Rscript -e "install.packages(c('languageserver', 'httpgd'), \
repos = c(runiverse='https://cran.r-universe.dev/bin/linux/noble-x86_64/4.5/', \
  nx10 = 'https://nx10.r-universe.dev/bin/linux/noble-x86_64/4.5/'))" \

[hturner]

Thanks for the correction @remlapmot. We don't want to hardcode the distro, architecture or R version, so we can do

Rscript -e "runiverse <- sprintf('r-universe.dev/bin/linux/%s-%s/%s/', \
                                 system2('lsb_release', '-sc', stdout = TRUE), \
                                 R.version\$arch, \
                                 substr(getRversion(), 1, 3)); \
            install.packages(c('languageserver', 'httpgd'), \
                 repos = c(runiverse = paste0('https://cran.', runiverse), \
                           nx10 = paste0('https://nx10.', runiverse)))"   

I've tested this out in a Rocker container to confirm it works.