How to Schedule R Scripts

Running R with taskscheduleR and cronR

In a previous post, we talked about how to run R from the Windows Task Scheduler. This article will talk about two additional approaches to schedule R scripts, including using the taskscheduleR package on Windows and the cronR package for Linux. For scheduling Python code, check out this post.

Schedule R scripts with taskscheduleR

Let’s install taskscheduleR using the install.packages command.

install.packages(“taskscheduleR”)

Next, we just need to load the package to get started.

library(taskscheduleR)

Creating a sample R script to run automatically

Before we do any scheduling, we need to first create a script. We’ll save the code below in a file called “create_file.txt”. This script will randomly generate a collection of integers and write them out to a file.

nums <- sample(10000, 100)

write(nums, “sample_nums.txt”)

Using the taskscheduler_create function

Next, in order to schedule the script to run automatically, we need to use the taskscheduler_create function. This function takes several arguments, which can be seen below.

taskscheduler_create(taskname = “test_run”, rscript = “/path/to/file/create_file.R”,
schedule = “ONCE”, starttime = format(Sys.time() + 50, “%H:%M”))

Firstly, we need to give a name to the task we want to create. In this case, we’ll just call our task “test_run”. Next, we need to specify the R script we want to automatically run. Third, we add the schedule parameter, which denotes how frequently we want to run this script. There are several options here, including WEEKLY, DAILY, MONTHLY, HOURLY, and MINUTE. For example, if we want our script to run every day, we would modify our function call like this:

taskscheduler_create(taskname = “test_run”, rscript = “/path/to/file/create_file.R”,
schedule = “DAILY”, starttime = format(Sys.time() + 50, “%H:%M”))

The other parameter we need to select is start time. In our examples, we’re setting the task to start in 50 seconds from the current time.

In addition to these arguments, taskscheduler_create also has a parameter called “modifier”. This allows us to modify the schedule frequency. For example, what if we want to run the task every 2 hours? In this case, we would just set modifier = 2.

taskscheduler_create(taskname = “test_run”, rscript = “/path/to/file/create_file.R”,
schedule = “HOURLY”, starttime = format(Sys.time() + 50, “%H:%M”), modifier = 2)

Similarly, we could run our script every 10 minutes using the code below, with a modifier of 10.

taskscheduler_create(taskname = “test_run”, rscript = “/path/to/file/create_file.R”,
schedule = “MINUTE”, starttime = format(Sys.time() + 50, “%H:%M”), modifier = 10)

Passing arguments to the Task Scheduler

We can pass arguments to the scheduled task using the “rscript_args” parameter.

taskscheduler_create(taskname = “test_run”, rscript = “/path/to/file/create_file.R”,
schedule = “MINUTE”, starttime = format(Sys.time() + 50, “%H:%M”), modifier = 10,
rscript_args = c(“10”, “test”, “this”))

Listing the tasks in the scheduler

What if we want to look at all the tasks currently in the task scheduler? There’s a quick method for that called taskscheduler_ls.

taskscheduler_ls()

Running this function returns a data frame of all the tasks currently in the task scheduler.

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Passing arguments to cronR

Running an R script with command line arguments is a common need. This can be handled with cronR using the “rscript_args” parameter in the cron_rscript function.

cmd <- cron_rscript("/path/to/file/create_file.R", rscript_args = c("10", "test", "this"))

cron_add(command = cmd, frequency = ‘/30 * * * *’, at = “15:00” , id = ‘test_linux_run’, description = “testing linux scheduler”)

Visit TheAutomatic.net to download ready-to-use code, and read the rest of the article: http://theautomatic.net/2020/05/12/how-to-schedule-r-scripts/