Add note in README

R/get_cache.R

@@ -12,8 +12,9 @@ import_ci_drake_cache <- function(tag = "master", gitlab_pat = Sys.getenv("GITLA
     httr::write_disk(zippath, overwrite = TRUE)
   )
   zip::unzip(zippath, exdir = file.path(td))
-  my_cache <- drake::drake_cache()
-  ci_cache <- drake::drake_cache(td)
+  if (!dir.exists(".drake")) drake::new_cache()
+  my_cache <- drake::drake_cache(path = ".drake")
+  ci_cache <- drake::drake_cache(path = file.path(td, ".drake"))
   my_cache$import(ci_cache)
   my_cache$history$import(ci_cache$history)
 }
\ No newline at end of file

README.md

@@ -10,7 +10,8 @@ Some key features:
 -   Outputs from the drake pipeline (model objects, compiled reports, and a drake network graph) go into `artifacts` when built.  This directory is stored as an artifact with each GitLab build job, but `.gitignore`'d.
 -   A [metrics file](https://docs.gitlab.com/ee/ci/metrics_reports.html) is saved
     on each run which can be read and reported by GitLab.
--   The `.drake` directory is `.gitignore`'d but cached on GitLab between jobs so as to minimize build times.
+-   The `.drake` directory is `.gitignore`'d but cached on GitLab between jobs so as to minimize build times.  It is also stored as a     an artifact (`artifacts/drake_cache.zip) so it may be downloaded and re-used.
+    -   An experimental function in `R/get_cache.R` imports the drake cache from GitLab CI into the local drake cache.  It requires a GitLab access token to be set a `GITLAB_PAT` in the environment (e.g., in `.Renviron`).
 -   A `Makefile` defines a docker command so that `make` builds the Docker environment and runs the `drake` pipeline inside it. This facilitates running the dockerized pipeline locally.
 -   The RStudio project file (`.Rproj`) is configured so that `make.R` is run using "Build All" (Cmd+Shift+B) in the Rstudio build pane.