packrat inside docker container

Dockerfile

# add this line to your Dockerfile (you also need to install Rbase)
RUN R -e 'install.packages("packrat" , repos="http://cran.us.r-project.org"); packrat::restore()'

packrat.R

# on your local machine install packrat
if (!require("devtools")) install.packages("devtools")
devtools::install_github("rstudio/packrat")
library(packrat)

# if this not work set lib path and repro, and try again 
# setRepositories(ind = c(1:6, 8))
# .libPaths( c("/path/to/your/R_library") )

# after installing, type in the following commands
packrat::init()
packrat::clean()
packrat::snapshot()

# then make sure the packrat.lock, packrat.opts, init.R 
# is located in the packrat/ folder and push these files to the repo if necessary 

thank you for this!

is there a reason for using http and not https for repos link, though? insecure http offers no security or server verification, so you might be downloading tampered packages.

....oh, probably because using https throws and error:

Warning: unable to access index for repository https://cran.us.r-project.org/src/contrib:
  cannot open URL 'https://cran.us.r-project.org/src/contrib/PACKAGES'
Warning message:
package ‘packrat’ is not available (for R version 3.5.1) 

:P