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authorJoey Hess2016-04-30 15:45:08 -0400
committerJoey Hess2016-04-30 15:45:08 -0400
commitfa75241024cc600390f36eba2c116f7110ab504f (patch)
tree01b8fd9e7ec0120544caed6a22e55fdd1db9f04d /src
parent2e513dc98c51eca1cdfce3715b4a017be39734f7 (diff)
parent9adfb7560fcd1186153bd743f885c12753abc9e5 (diff)
Merge remote-tracking branch 'felix/attic' into joeyconfig
Diffstat (limited to 'src')
-rw-r--r--src/Propellor/Property/Attic.hs103
1 files changed, 81 insertions, 22 deletions
diff --git a/src/Propellor/Property/Attic.hs b/src/Propellor/Property/Attic.hs
index 0fadc113..26f23500 100644
--- a/src/Propellor/Property/Attic.hs
+++ b/src/Propellor/Property/Attic.hs
@@ -25,6 +25,7 @@ installed = Apt.installed ["attic"]
repoExists :: AtticRepo -> IO Bool
repoExists repo = boolSystem "attic" [Param "list", File repo]
+-- | Inits a new attic repository
init :: AtticRepo -> Property DebianLike
init backupdir = check (not <$> repoExists backupdir) (cmdProperty "attic" initargs)
`requires` installed
@@ -34,45 +35,99 @@ init backupdir = check (not <$> repoExists backupdir) (cmdProperty "attic" inita
, backupdir
]
-restored :: [FilePath] -> AtticRepo -> Property DebianLike
-restored dirs backupdir = cmdProperty "attic" restoreargs
- `assume` MadeChange
- `describe` ("attic restore from " ++ backupdir)
- `requires` installed
+-- | Restores a directory from an attic 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 -> AtticRepo -> Property DebianLike
+restored dir backupdir = go `requires` installed
where
- restoreargs =
- [ "extract"
- , backupdir
- ]
- ++ dirs
+ go :: Property DebianLike
+ go = property (dir ++ " restored by attic") $ ifM (liftIO needsRestore)
+ ( do
+ warningMessage $ dir ++ " is empty/missing; restoring from backup ..."
+ liftIO restore
+ , noChange
+ )
+
+ needsRestore = null <$> catchDefaultIO [] (dirContents dir)
-backup :: [FilePath] -> AtticRepo -> Cron.Times -> [AtticParam] -> [KeepPolicy] -> Property DebianLike
-backup dirs backupdir crontimes extraargs kp = propertyList (backupdir ++ " attic backup") $ props
- & check (not <$> repoExists backupdir) (restored dirs backupdir)
- & Cron.niceJob ("attic_backup" ++ backupdir) crontimes (User "root") "/" backupcmd
+ restore = withTmpDirIn (takeDirectory dir) "attic-restore" $ \tmpdir -> do
+ ok <- boolSystem "attic" $
+ [ Param "extract"
+ , Param backupdir
+ , Param 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 attic 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:
+--
+-- > & Attic.backup "/srv/git" "root@myserver:/mnt/backup/git.attic" Cron.Daily
+-- > ["--exclude=/srv/git/tobeignored"]
+-- > [Attic.KeepDays 7, Attic.KeepWeeks 4, Attic.KeepMonths 6, Attic.KeepYears 1]
+--
+-- Note that this property does not make attic encrypt the backup
+-- repository.
+--
+-- Since attic uses a fair amount of system resources, only one attic
+-- backup job will be run at a time. Other jobs will wait their turns to
+-- run.
+backup :: FilePath -> AtticRepo -> Cron.Times -> [AtticParam] -> [KeepPolicy] -> Property DebianLike
+backup dir backupdir crontimes extraargs kp = backup' dir backupdir crontimes extraargs kp
+ `requires` restored dir backupdir
+
+-- | Does a backup, but does not automatically restore.
+backup' :: FilePath -> AtticRepo -> Cron.Times -> [AtticParam] -> [KeepPolicy] -> Property DebianLike
+backup' dir backupdir crontimes extraargs kp = cronjob
+ `describe` desc
`requires` installed
where
- backupcmd = intercalate ";"
- [ createCommand
- , pruneCommand
- ]
+ desc = backupdir ++ " attic backup"
+ cronjob = Cron.niceJob ("attic_backup" ++ dir) crontimes (User "root") "/" $
+ "flock " ++ shellEscape lockfile ++ " sh -c " ++ backupcmd
+ lockfile = "/var/lock/propellor-attic.lock"
+ backupcmd = intercalate ";" $
+ createCommand
+ : if null kp then [] else [pruneCommand]
createCommand = unwords $
[ "attic"
, "create"
, "--stats"
]
- ++ extraargs ++
- [ backupdir ++ "::" ++ "$(date --iso-8601=ns --utc)"
- , unwords dirs
+ ++ map shellEscape extraargs ++
+ [ shellEscape backupdir ++ "::" ++ "$(date --iso-8601=ns --utc)"
+ , shellEscape dir
]
pruneCommand = unwords $
[ "attic"
, "prune"
- , backupdir
+ , shellEscape backupdir
]
++
map keepParam kp
+-- | Constructs an AtticParam 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 attic prune to clean out
+-- generations not specified here.
keepParam :: KeepPolicy -> AtticParam
keepParam (KeepHours n) = "--keep-hourly=" ++ show n
keepParam (KeepDays n) = "--keep-daily=" ++ show n
@@ -80,6 +135,10 @@ keepParam (KeepWeeks n) = "--keep-daily=" ++ show n
keepParam (KeepMonths n) = "--keep-monthly=" ++ show n
keepParam (KeepYears n) = "--keep-yearly=" ++ show 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 attic's man page for details.
data KeepPolicy
= KeepHours Int
| KeepDays Int