introduction_renv.Rmd

---
title: "Package management with `renv`"
author: "Jonas Hagenberg"
date: "17.11.2021"
output:
  xaringan::moon_reader:
    css: xaringan-themer.css
    lib_dir: libs
    nature:
      highlightStyle: github
      highlightLines: true
      countIncrementalSlides: false
---

```{r setup, include=FALSE}
options(htmltools.dir.version = FALSE)
```

```{r xaringan-themer, include=FALSE, warning=FALSE}
library(xaringanthemer)
style_duo_accent(
  primary_color = "#1a5f96",
  secondary_color = "#03A696",
  code_inline_background_color = "#f8f8f8"
)
```

# What is package management?

- control the versions of the packages you use

--

- make your analysis reproducible -> for your future you or a collaborator

--

- from `R`: `packrat`, from `python`: `venv`, `conda`

--

- for every project/analysis, you can use a different set of packages/versions

---

# Why `renv`?

- newest tool that is under active development by `rstudio`

--

- lightweight and easy to get started

--

- can be used to support more complicated use cases, e.g. combine containers
with a custom library on the cluster

---

# How to use it

1. install it:
    ```{r, eval = FALSE}
    install.packages("renv")
    ```

--
2. create a new  RStudio project

--
3. initialise `renv`:
    ```{r, eval = FALSE}
    renv::init()
    ```

--
4. work normally on your project, install packages (or update them with
`renv::update()`)

--
5. when you want to save the new status of your packages, use
    ```{r, eval = FALSE}
    renv::snapshot()
    ```

???
do a live presentation here: start a new project, initialise R, install a
package, use it in a script, snapshot, look at lockfile

---

# How does it work?

- `renv` uses a private package library specific for each project

--

- the packages are copied from a central `renv` package cache on your computer,
so that they don't need to be installed from CRAN every time

--

- the package versions are stored in `renv.lock` in a json format. This can be
added to version control and others can use the lockfile

--

- `renv` automatically discovers which packages are used in your projects
(by inspecting `library` calls and `library::function` syntax)

???
this means that it can also be introduced into an already existing project

---

# Caveats

- only the package & `R` versions are recorded, nothing else (e.g. no system
libraries)

--

- if you want absolute control, use container

--

- recorded package versions could not be available at a later point of time

---

# More information

Look at the official [documentation](https://rstudio.github.io/renv/articles/renv.html)