This is a scheduling package for running one-off or recurring tasks in second-precision schedules. It may be useful either in maintenance tasks, or in batch processing pipelines where new data are made available periodically. For example, you may need to retrieve new records written in a database every 30 seconds and process them in batches.
Development version from GitHub
install.packages("devtools")
devtools::install_github("henfiber/cronr")
Then load it as usually
library('cronr')
Here is how to use the main scheduling function crond.
Firtly, define a "task handler" function which will be responsible for executing your tasks:
my_handler <- function(task_id, timestamp, tasks_info) {
# Do something with this "task_id" using the information in "tasks_info"
message("Running ", task_id, " at ", unclass(Sys.time()), " - scheduled: ",
timestamp, " (", as.POSIXct(timestamp, origin = "1970-01-01") , ")")
}
Then define some tasks in a data frame or other structure. The scheduling definitions are expressed in a "period:offset" notation, meaning that a task will run every "period" units, waiting "offset" units before running the task. Units are specified in shorthand form, e.g. "1m" for "1 minute", "2h" for 2 hours etc.
my_tasks <- data.frame(schedules = c("2s", "1m:3s", "1h:5s"),
my_jobs = c("job01", "job02", "job03"),
other_info = c("...", "...", "..."),
stringsAsFactors = F)
schedules <- my_tasks$schedules
Then start the scheduler using the crond function
crond(schedules, my_tasks, "callback", "my_handler")
The scheduler will run indefinitely in the background until you interrupt the R session.
GPLv2 or newer
Copyright 2014-2017 Ilias Kotinas