Skip to contents

Create a Lockfile to Reproduce Reactives

Source: R/reprex_lockfile.R
reprex_lockfile.Rd

Capture the exact package versions, sources and R version needed to reproduce one or more shiny::reactive objects, as an renv lockfile. Restoring the lockfile with renv::restore() recreates the environment the reactives were generated in, including the recursive dependency tree.

A single lockfile covers every reactive passed, so an application can offer one download that reproduces all of its outputs.

Snapshot Scope

The snapshot is taken from the currently loaded library (.libPaths()), so the versions recorded are exactly those the running Shiny session used to produce the reactives. renv resolves and records the full recursive dependency tree of packages, so only the top-level set needs to be supplied.

Isolation

The snapshot runs against a throwaway temporary project, so it never writes renv infrastructure into, or otherwise modifies, the application's own directory.

Output Path

A relative lockfile is resolved against the working directory, not against the temporary project used for the snapshot. The default therefore writes renv.lock into whichever directory the application is running from. Pass an absolute path to control where it lands; inside a shiny::downloadHandler() that is the file argument.

Usage

reprex_lockfile(
  ...,
  packages = NULL,
  lockfile = "renv.lock",
  exclude = NULL,
  session = shiny::getDefaultReactiveDomain()
)

Arguments

...

One or more shiny::reactive objects to reproduce. If none are supplied, every reactive registered by register_reactives() is used, so a modular application can offer a whole-app lockfile without threading reactives up to the top level.

packages

Character vector of package names to snapshot. If NULL (the default), every package detected across ... is used. Supplying this lets the user narrow the set, or add a package the detector could not find (for example one attached only for an operator or method).

lockfile

Path to write the lockfile to. Defaults to "renv.lock".

exclude

Character vector of package names to omit from the snapshot.

session

The Shiny session to read registered reactives from. Only used when ... is empty and packages is NULL.

Value

The absolute path the lockfile was written to, invisibly.

See also

reprex_packages() to inspect the detected set without writing a lockfile, and register_reactives() to record reactives from within each module.

Examples

if (FALSE) { # interactive()
library(shiny)

numeric_iris <- reactive(purrr::keep(iris, is.numeric))

isolate(reprex_lockfile(numeric_iris, lockfile = tempfile(fileext = ".lock")))
}