propellor/src/Propellor/Property/Cron.hs

62 lines
2.1 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 Utility.FileMode
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.
--
-- The cron job's output will only be emailed if it exits nonzero.
job :: Desc -> CronTimes -> UserName -> FilePath -> String -> Property NoInfo
job desc times user cddir command = combineProperties ("cronned " ++ desc)
[ 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 ++ "\tchronic " ++ shellEscape scriptfile
]
-- Use a separate script because it makes the cron job name
-- prettier in emails, and also allows running the job manually.
, scriptfile `File.hasContent`
[ "#!/bin/sh"
, "# Generated by propellor"
, "set -e"
, "flock -n " ++ shellEscape cronjobfile
++ " sh -c " ++ shellEscape cmdline
]
, scriptfile `File.mode` combineModes (readModes ++ executeModes)
]
`requires` Apt.serviceInstalledRunning "cron"
`requires` Apt.installed ["util-linux", "moreutils"]
where
cmdline = "cd " ++ cddir ++ " && ( " ++ command ++ " )"
cronjobfile = "/etc/cron.d/" ++ name
scriptfile = "/usr/local/bin/" ++ name ++ "_cronjob"
name = 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 NoInfo
niceJob desc times user cddir command = job desc times user cddir
("nice ionice -c 3 sh -c " ++ shellEscape command)
-- | Installs a cron job to run propellor.
runPropellor :: CronTimes -> Property NoInfo
runPropellor times = niceJob "propellor" times "root" localdir "./propellor"