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authorFélix Sipma2017-04-27 14:57:12 +0200
committerFélix Sipma2017-04-27 14:58:27 +0200
commitfe4b58f7db06cd59b95e73ef2a664372d0a4addd (patch)
tree3419a194920cbe039ca372d8989ae13b2e46e9af /src/Propellor/Property/Restic.hs
parent83cb0710384c7fba157d8b32f3b90b488b7c1e60 (diff)
add Restic module
Diffstat (limited to 'src/Propellor/Property/Restic.hs')
-rw-r--r--src/Propellor/Property/Restic.hs204
1 files changed, 204 insertions, 0 deletions
diff --git a/src/Propellor/Property/Restic.hs b/src/Propellor/Property/Restic.hs
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+-- | Maintainer: Félix Sipma <felix+propellor@gueux.org>
+--
+-- Support for the restic backup tool <https://github.com/restic/restic>
+
+module Propellor.Property.Restic
+ ( ResticRepo (..)
+ , installed
+ , repoExists
+ , init
+ , restored
+ , backup
+ , KeepPolicy (..)
+ ) where
+
+import Propellor.Base hiding (init)
+import Prelude hiding (init)
+import qualified Propellor.Property.Apt as Apt
+import qualified Propellor.Property.Cron as Cron
+import qualified Propellor.Property.File as File
+import Data.List (intercalate)
+
+type Url = String
+
+type ResticParam = String
+
+data ResticRepo
+ = Direct FilePath
+ | SFTP User HostName FilePath
+ | REST Url
+
+instance ConfigurableValue ResticRepo where
+ val (Direct fp) = fp
+ val (SFTP u h fp) = "sftp:" ++ val u ++ "@" ++ val h ++ ":" ++ fp
+ val (REST url) = "rest:" ++ url
+
+installed :: Property DebianLike
+installed = withOS desc $ \w o -> case o of
+ (Just (System (Debian _ (Stable "jessie")) _)) -> ensureProperty w $
+ Apt.installedBackport ["restic"]
+ _ -> ensureProperty w $
+ Apt.installed ["restic"]
+ where
+ desc = "installed restic"
+
+repoExists :: ResticRepo -> IO Bool
+repoExists repo = boolSystem "restic"
+ [ Param "-r"
+ , File (val repo)
+ , Param "--password-file"
+ , File (getPasswordFile repo)
+ , Param "snapshots"
+ ]
+
+passwordFileDir :: FilePath
+passwordFileDir = "/etc/restic-keys"
+
+getPasswordFile :: ResticRepo -> FilePath
+getPasswordFile repo = passwordFileDir </> File.configFileName (val repo)
+
+passwordFileConfigured :: ResticRepo -> Property (HasInfo + UnixLike)
+passwordFileConfigured repo = propertyList "restic password file" $ props
+ & File.dirExists passwordFileDir
+ & File.mode passwordFileDir 0O2700
+ & getPasswordFile repo `File.hasPrivContent` hostContext
+
+-- | Inits a new restic repository
+init :: ResticRepo -> Property (HasInfo + DebianLike)
+init repo = check (not <$> repoExists repo) (cmdProperty "restic" initargs)
+ `requires` installed
+ `requires` passwordFileConfigured repo
+ where
+ initargs =
+ [ "-r"
+ , val repo
+ , "--password-file"
+ , getPasswordFile repo
+ , "init"
+ ]
+
+-- | Restores a directory from a restic backup.
+--
+-- Only does anything if the directory does not exist, or exists,
+-- but is completely empty.
+--
+-- The restore is performed atomically; restoring to a temp directory
+-- and then moving it to the directory.
+restored :: FilePath -> ResticRepo -> Property (HasInfo + DebianLike)
+restored dir repo = go
+ `requires` installed
+ `requires` passwordFileConfigured repo
+ where
+ go :: Property DebianLike
+ go = property (dir ++ " restored by restic") $ ifM (liftIO needsRestore)
+ ( do
+ warningMessage $ dir ++ " is empty/missing; restoring from backup ..."
+ liftIO restore
+ , noChange
+ )
+
+ needsRestore = null <$> catchDefaultIO [] (dirContents dir)
+
+ restore = withTmpDirIn (takeDirectory dir) "restic-restore" $ \tmpdir -> do
+ ok <- boolSystem "restic"
+ [ Param "-r"
+ , File (val repo)
+ , Param "--password-file"
+ , File (getPasswordFile repo)
+ , Param "restore"
+ , Param "latest"
+ , Param "--target"
+ , File tmpdir
+ ]
+ let restoreddir = tmpdir ++ "/" ++ dir
+ ifM (pure ok <&&> doesDirectoryExist restoreddir)
+ ( do
+ void $ tryIO $ removeDirectory dir
+ renameDirectory restoreddir dir
+ return MadeChange
+ , return FailedChange
+ )
+
+-- | Installs a cron job that causes a given directory to be backed
+-- up, by running borg with some parameters.
+--
+-- If the directory does not exist, or exists but is completely empty,
+-- this Property will immediately restore it from an existing backup.
+--
+-- So, this property can be used to deploy a directory of content
+-- to a host, while also ensuring any changes made to it get backed up.
+-- For example:
+--
+-- > & Restic.backup "/srv/git"
+-- > (Restic.SFTP (User root) (HostName myserver) /mnt/backup/git.restic")
+-- > Cron.Daily
+-- > ["--exclude=/srv/git/tobeignored"]
+-- > [Restic.KeepDays 7, Restic.KeepWeeks 4, Restic.KeepMonths 6, Restic.KeepYears 1]
+--
+-- Since restic uses a fair amount of system resources, only one restic
+-- backup job will be run at a time. Other jobs will wait their turns to
+-- run.
+backup :: FilePath -> ResticRepo -> Cron.Times -> [ResticParam] -> [KeepPolicy] -> Property (HasInfo + DebianLike)
+backup dir repo crontimes extraargs kp = backup' dir repo crontimes extraargs kp
+ `requires` restored dir repo
+
+-- | Does a backup, but does not automatically restore.
+backup' :: FilePath -> ResticRepo -> Cron.Times -> [ResticParam] -> [KeepPolicy] -> Property (HasInfo + DebianLike)
+backup' dir repo crontimes extraargs kp = cronjob
+ `describe` desc
+ `requires` installed
+ `requires` passwordFileConfigured repo
+ where
+ desc = val repo ++ " restic backup"
+ cronjob = Cron.niceJob ("restic_backup" ++ dir) crontimes (User "root") "/" $
+ "flock " ++ shellEscape lockfile ++ " sh -c " ++ backupcmd
+ lockfile = "/var/lock/propellor-restic.lock"
+ backupcmd = intercalate ";" $
+ createCommand
+ : if null kp then [] else [pruneCommand]
+ createCommand = unwords $
+ [ "restic"
+ , "-r"
+ , val repo
+ , "--password-file"
+ , getPasswordFile repo
+ ]
+ ++ map shellEscape extraargs ++
+ [ "backup"
+ , shellEscape dir
+ ]
+ pruneCommand = unwords $
+ [ "restic"
+ , "-r"
+ , val repo
+ , "--password-file"
+ , getPasswordFile repo
+ , "forget"
+ , "--prune"
+ ]
+ ++
+ map keepParam kp
+
+-- | Constructs a ResticParam that specifies which old backup generations to
+-- keep. By default, all generations are kept. However, when this parameter is
+-- passed to the `backup` property, they will run restic prune to clean out
+-- generations not specified here.
+keepParam :: KeepPolicy -> ResticParam
+keepParam (KeepLast n) = "--keep-last=" ++ val n
+keepParam (KeepHours n) = "--keep-hourly=" ++ val n
+keepParam (KeepDays n) = "--keep-daily=" ++ val n
+keepParam (KeepWeeks n) = "--keep-weekly=" ++ val n
+keepParam (KeepMonths n) = "--keep-monthly=" ++ val n
+keepParam (KeepYears n) = "--keep-yearly=" ++ val n
+
+-- | Policy for backup generations to keep. For example, KeepDays 30 will
+-- keep the latest backup for each day when a backup was made, and keep the
+-- last 30 such backups. When multiple KeepPolicies are combined together,
+-- backups meeting any policy are kept. See borg's man page for details.
+data KeepPolicy
+ = KeepLast Int
+ | KeepHours Int
+ | KeepDays Int
+ | KeepWeeks Int
+ | KeepMonths Int
+ | KeepYears Int