README.md
In cronR: Schedule R Scripts and Processes with the 'cron' Job Scheduler

cronR

Schedule R scripts/processes with the cron scheduler. This allows R users working on Unix/Linux to automate R processes at specific timepoints from R itself. Note that if you are looking for a Windows scheduler, you might be interested in the R package taskscheduleR available at https://github.com/bnosac/taskscheduleR

This R package allows you to

Get the list of scheduled jobs
Remove scheduled jobs
Add a job
A job is basically a script with R code which is run through Rscript
You can schedule tasks 'ONCE', 'EVERY MINUTE', 'EVERY HOUR', 'EVERY DAY', 'EVERY WEEK', 'EVERY MONTH' or any complex schedule
The task log contains the stdout & stderr of the Rscript which was run on that timepoint. This log can be found at the same folder as the R script

The package also contains an RStudio addin. If you install the package and use RStudio version 0.99.893 or later you can just click to schedule a task. Just click Addins > Schedule R scripts on Linux/Unix.

Alternatively, run cronR::cron_rstudioaddin() to open the addin interface. If you use that addin to schedule scripts, by default it will copy the R scripts to your current working directory and launch the copied scripts from there. A different directory can be specified by passing an argument to the RscriptRepository parameter cronR::cron_rstudioaddin(RscriptRepository = "/path/to/your/deployment/directory")
You can also set the CRON_LIVE environment variable to specify a default directory to copy scheduled scripts to. This can be done by putting something like CRON_LIVE="/path/to/your/deployment/directory" in your .Renviron or .Rprofile file. See ?Startup

Some example use cases are shown below, indicating to schedule a script at specific timepoints.

library(cronR)
f   <- system.file(package = "cronR", "extdata", "helloworld.R")
cmd <- cron_rscript(f)
cmd

cron_add(command = cmd, frequency = 'minutely', id = 'test1', description = 'My process 1', tags = c('lab', 'xyz'))
cron_add(command = cmd, frequency = 'daily', at='7AM', id = 'test2')
cron_njobs()

cron_ls()
cron_clear(ask = TRUE)
cron_ls()

cmd <- cron_rscript(f, rscript_args = c("productx", "arg2", "123"))
cmd
cron_add(cmd, frequency = 'minutely', id = 'job1', description = 'Customers')
cron_add(cmd, frequency = 'hourly', id = 'job2', description = 'Weather')
cron_add(cmd, frequency = 'hourly', id = 'job3', days_of_week = c(1, 2))
cron_add(cmd, frequency = 'hourly', id = 'job4', at = '00:20', days_of_week = c(1, 2))
cron_add(cmd, frequency = 'daily', id = 'job5', at = '14:20')
cron_add(cmd, frequency = 'daily', id = 'job6', at = '14:20', days_of_week = c(0, 3, 5))
cron_add(cmd, frequency = 'daily', id = 'job7', at = '23:59', days_of_month = c(1, 30))
cron_add(cmd, frequency = 'monthly', id = 'job8', at = '10:30', days_of_month = 'first', days_of_week = '*')
cron_add(cmd, frequency = '@reboot', id = 'job9', description = 'Good morning')
cron_add(cmd, frequency = '*/15 * * * *', id = 'job10', description = 'Every 15 min')   
cron_ls()
cron_clear(ask = TRUE)

By default, when you use the functions cron_add, cron_rm, cron_clear, cron_load, a prompt will ask for your permission to update the cron schedule, unless you put the argument ask=FALSE in each of these functions, in which case you automatically allow to update the schedule. (new since R package version 0.6.0)

Make sure the cron daemon (https://en.wikipedia.org/wiki/Cron) is running. On Debian this is done as follows.

sudo apt-get update
sudo apt-get install -y cron
sudo cron start

For regular users, install the package from your local CRAN mirror with install.packages("cronR"), for installing the development version of this package: remotes::install_github("bnosac/cronR")
If you want the RStudio add-in to work, also install miniUI, shiny and shinyFiles

install.packages("cronR")
install.packages('miniUI')
install.packages('shiny')
install.packages('shinyFiles')

Now have a look at ?cron_add or start the RStudio addin

Consider adding options(echo = TRUE) at the start of your R scripts in order to debug your scripts in case of errors.
Consider using argument env when calling cron_add if you need specific environment variables to be used in your script, These will be prepended to your script. E.g. as follows where you replace dry_run to FALSE to add it to your cron job list.

cmd <- cron_rscript("/path/to/your/script.R")
cron_add(cmd, frequency = 'minutely', id = 'job1', description = 'Customers', 
         env = c(LANG = "en_US.UTF-8", R_LIBS_USER = Sys.getenv("R_LIBS_USER"), YOUR_PROJECT_XYZ = getwd()), 
         ask = FALSE, dry_run = TRUE)

Currently, cronR does not preserve or handle cron jobs not generated through the package. This will be handled some time in the future. To be safe, you should run cron_save("cron.backup") before fiddling around.