lib2.R

# probably needs to do something to inform R that a new package is available?
# the code can be used but will installed.packages() work properly?
lib2 = function(pkgname, dry.run=TRUE, repos=BiocManager::repositories(), 
    character.only=FALSE, source_gs="gs://biocbbs_2020a/packs_3.10/", 
    target=.libPaths()[1], ...) {
 if (!character.only) pkgname = as.character(substitute(pkgname))
 stopifnot(is.character(pkgname) && is.atomic(pkgname) && length(pkgname)==1)
# verify need
 ino = options(no.readonly=TRUE)
 options(repos=repos)
 already_in = rownames(installed.packages())
 if (pkgname %in% already_in) return(base::library(pkgname, character.only=TRUE, ...))
# make sure you can get into target folder
 tst = try(setwd(target)) # now in future .libPaths
 if (inherits(tst, "try-error")) stop("can't change folder to target")
# learn dependencies needed
 deps = tools::package_dependencies(pkgname)
 nd = names(deps)
 deps = unique(c(nd, unlist(deps)))
 must_get = setdiff(deps, already_in)
 if (length(must_get)==0) return(base::library(pkgname))
 curd = getwd()
 on.exit({options(ino); setwd(curd)})
 if (dry.run) return(list(msg=paste0("dry.run = TRUE so not installing from ", source_gs), deps=deps,
    must_get=must_get))
 for (i in must_get) {
   dir.create(i)
   setwd(i)
   localize(paste0(source_gs, i), ".", dry=FALSE) # could use gsutil_cp
   setwd("..")
   }
 base::library(pkgname, character.only=TRUE)
}