propellor/Propellor/Property/Cron.hs

48 lines
1.6 KiB
Haskell

module Propellor.Property.Cron where
import Propellor
import qualified Propellor.Property.File as File
import qualified Propellor.Property.Apt as Apt
import Utility.SafeCommand
import Data.Char
type CronTimes = String
-- | Installs a cron job, run as a specified user, in a particular
-- directory. Note that the Desc must be unique, as it is used for the
-- cron.d/ filename.
--
-- Only one instance of the cron job is allowed to run at a time, no matter
-- how long it runs. This is accomplished using flock locking of the cron
-- job file.
job :: Desc -> CronTimes -> UserName -> FilePath -> String -> Property
job desc times user cddir command = cronjobfile `File.hasContent`
[ "# Generated by propellor"
, ""
, "SHELL=/bin/sh"
, "PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin"
, ""
, times ++ "\t" ++ user ++ "\t"
++ "flock -n " ++ shellEscape cronjobfile
++ " -c sh -c " ++ shellEscape cmdline
]
`requires` Apt.serviceInstalledRunning "cron"
`describe` ("cronned " ++ desc)
where
cmdline = "cd " ++ cddir ++ " && " ++ command
cronjobfile = "/etc/cron.d/" ++ map sanitize desc
sanitize c
| isAlphaNum c = c
| otherwise = '_'
-- | Installs a cron job, and runs it niced and ioniced.
niceJob :: Desc -> CronTimes -> UserName -> FilePath -> String -> Property
niceJob desc times user cddir command = job desc times user cddir
("nice ionice -c 3 " ++ command)
`requires` Apt.installed ["util-linux", "moreutils"]
-- | Installs a cron job to run propellor.
runPropellor :: CronTimes -> Property
runPropellor times = niceJob "propellor" times "root" localdir "chronic make"