If you are administering Posit Connect in an offline environment, you’ll need to follow certain steps to ensure the R packages used by your team are available in Connect. These steps are different from the process you might have used in the past to provide packages to RStudio.
The first option is to check and see if your networking team will allow outbound access to CRAN, by enabling access to https://cran.rstudio.com. The admin guide contains instructions for configuring Posit Connect to use an outbound proxy for package downloads. If you are not able to access an online repository, you will need to create and administer your own package repository.
The remainder of this article documents the background information and steps for doing so. The easiest way to administer a package repository for R is using Posit Package Manager.
Package Library vs Package Repository
A repository is a directory containing uninstalled R source files or platform-specific binaries. A repository contains a PACKAGES file with important information about the repository’s content.
A library is a directory containing installed R packages.
Though a repository and a library look very similar, they are two distinct entities.
Usually, two steps are required to use an R package:
- The package is installed from a repository into a library using
install.packages(). - The package is loaded from the library for an analysis using
library().
In offline Workbench environments, it is common for administers to skip setting up a local package repository, and instead install packages directly from an online CRAN repository into a system library. The system library - a set of folders - is then moved to the offline environment or located on shared storage. R users access packages from the system library using the library() function. The administrator tells R to look in the correct directory by defining R_LIBS_SITE in the Renviron.site file or using the R function .libPaths() in the Rprofile.site file.
Offline use of Posit Connect, however, requires admins to set up a package repository. This requirement is necessary to enable Connect to manage and isolate package dependencies for deployed content. In brief, Connect installs packages from the local repository into private libraries for each piece of deployed content. Individual libraries guarantee that the content will have the correct packages, even if other content on the server requires a different version of the same package. (In practice, the process is optimized to cache packages while guaranteeing the correct versions are always available).
In environments with both Posit Workbench and Posit Connect, a local package repository should be used for both. Specifically, users or administrators should install packages in Posit Workbench's system library from the local repository. Installing packages into the system library from a different repository can result in a mismatch between Connect and Workbench that will cause deployment failures.
Setting up a local repository
To make the process of creating a local repository easy, we've built a product called Posit Package Manager. Posit Package Manager provides a holistic strategy for managing R packages in your organization, and it is built to work with Posit Workbench and Posit Connect.
There are open-source alternatives for managing local repositories, including the miniCRAN and packrat R packages. Posit can not provide support for these open source alternatives.
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