add ConfigMonitor thread

Monitors git-annex branch for changes, which are noticed by the Merger
thread whenever the branch ref is changed (either due to an incoming push,
or a local change), and refreshes cached config values for modified config
files.

Rate limited to run no more often than once per minute. This is important
because frequent git-annex branch changes happen when files are being
added, or transferred, etc.

A primary use case is that, when preferred content changes are made,
and get pushed to remotes, the remotes start honoring those settings.
Other use cases include propigating repository description and trust
changes to remotes, and learning when a remote has added a new special
remote, so the webapp can present the GUI to enable that special remote
locally.

Also added a uuid.log cache. All other config files already had caches.
This commit is contained in:
Joey Hess 2012-10-20 16:37:06 -04:00
parent b281584422
commit c7c2015435
14 changed files with 216 additions and 63 deletions

View file

@ -0,0 +1,90 @@
{- git-annex assistant config monitor thread
-
- Copyright 2012 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Assistant.Threads.ConfigMonitor where
import Assistant.Common
import Assistant.BranchChange
import Assistant.ThreadedMonad
import Assistant.DaemonStatus
import Utility.ThreadScheduler
import Logs.UUID
import Logs.Trust
import Logs.Remote
import Logs.PreferredContent
import Logs.Group
import Remote.List (remoteListRefresh)
import qualified Git
import qualified Git.LsTree as LsTree
import qualified Annex.Branch
import qualified Annex
import qualified Data.Set as S
thisThread :: ThreadName
thisThread = "ConfigMonitor"
{- This thread detects when configuration changes have been made to the
- git-annex branch and reloads cached configuration.
-
- If the branch is frequently changing, it's checked for configuration
- changes no more often than once every 60 seconds. On the other hand,
- if the branch has not changed in a while, configuration changes will
- be detected immediately.
-}
configMonitorThread :: ThreadState -> DaemonStatusHandle -> BranchChangeHandle -> NamedThread
configMonitorThread st dstatus branchhandle = thread $ do
r <- runThreadState st Annex.gitRepo
go r =<< getConfigs r
where
thread = NamedThread thisThread
go r old = do
threadDelaySeconds (Seconds 60)
waitBranchChange branchhandle
new <- getConfigs r
when (old /= new) $ do
let changedconfigs = new `S.difference` old
debug thisThread $ "reloading config" :
map fst (S.toList changedconfigs)
reloadConfigs st dstatus changedconfigs
go r new
{- Config files, and their checksums. -}
type Configs = S.Set (FilePath, String)
{- All git-annex's config files, and actions to run when they change. -}
configFilesActions :: [(FilePath, Annex ())]
configFilesActions =
[ (uuidLog, void $ uuidMapLoad)
, (remoteLog, void remoteListRefresh)
, (trustLog, void trustMapLoad)
, (groupLog, void groupMapLoad)
-- Preferred content settings depend on most of the other configs,
-- so will be reloaded whenever any configs change.
, (preferredContentLog, noop)
]
reloadConfigs :: ThreadState -> DaemonStatusHandle -> Configs -> IO ()
reloadConfigs st dstatus changedconfigs = runThreadState st $ do
sequence_ as
void preferredContentMapLoad
{- Changes to the remote log, or the trust log, can affect the
- syncRemotes list -}
when (Logs.Remote.remoteLog `elem` fs || Logs.Trust.trustLog `elem` fs) $
updateSyncRemotes dstatus
where
(fs, as) = unzip $ filter (flip S.member changedfiles . fst)
configFilesActions
changedfiles = S.map fst changedconfigs
getConfigs :: Git.Repo -> IO Configs
getConfigs r = S.fromList . map extract
<$> LsTree.lsTreeFiles Annex.Branch.fullname files r
where
files = map fst configFilesActions
extract treeitem = (LsTree.file treeitem, LsTree.sha treeitem)

View file

@ -11,6 +11,7 @@ import Assistant.Common
import Assistant.ThreadedMonad
import Assistant.DaemonStatus
import Assistant.TransferQueue
import Assistant.BranchChange
import Utility.DirWatcher
import Utility.Types.DirWatcher
import qualified Annex.Branch
@ -23,12 +24,12 @@ thisThread = "Merger"
{- This thread watches for changes to .git/refs/, and handles incoming
- pushes. -}
mergeThread :: ThreadState -> DaemonStatusHandle -> TransferQueue -> NamedThread
mergeThread st dstatus transferqueue = thread $ do
mergeThread :: ThreadState -> DaemonStatusHandle -> TransferQueue -> BranchChangeHandle -> NamedThread
mergeThread st dstatus transferqueue branchchange = thread $ do
g <- runThreadState st gitRepo
let dir = Git.localGitDir g </> "refs"
createDirectoryIfMissing True dir
let hook a = Just $ runHandler st dstatus transferqueue a
let hook a = Just $ runHandler st dstatus transferqueue branchchange a
let hooks = mkWatchHooks
{ addHook = hook onAdd
, errHook = hook onErr
@ -38,21 +39,21 @@ mergeThread st dstatus transferqueue = thread $ do
where
thread = NamedThread thisThread
type Handler = ThreadState -> DaemonStatusHandle -> TransferQueue -> FilePath -> Maybe FileStatus -> IO ()
type Handler = ThreadState -> DaemonStatusHandle -> TransferQueue -> BranchChangeHandle -> FilePath -> Maybe FileStatus -> IO ()
{- Runs an action handler.
-
- Exceptions are ignored, otherwise a whole thread could be crashed.
-}
runHandler :: ThreadState -> DaemonStatusHandle -> TransferQueue -> Handler -> FilePath -> Maybe FileStatus -> IO ()
runHandler st dstatus transferqueue handler file filestatus = void $
runHandler :: ThreadState -> DaemonStatusHandle -> TransferQueue -> BranchChangeHandle -> Handler -> FilePath -> Maybe FileStatus -> IO ()
runHandler st dstatus transferqueue branchchange handler file filestatus = void $
either print (const noop) =<< tryIO go
where
go = handler st dstatus transferqueue file filestatus
go = handler st dstatus transferqueue branchchange file filestatus
{- Called when there's an error with inotify. -}
onErr :: Handler
onErr _ _ _ msg _ = error msg
onErr _ _ _ _ msg _ = error msg
{- Called when a new branch ref is written.
-
@ -66,11 +67,13 @@ onErr _ _ _ msg _ = error msg
- ran are merged in.
-}
onAdd :: Handler
onAdd st dstatus transferqueue file _
onAdd st dstatus transferqueue branchchange file _
| ".lock" `isSuffixOf` file = noop
| isAnnexBranch file = runThreadState st $
whenM Annex.Branch.forceUpdate $
queueDeferredDownloads Later transferqueue dstatus
| isAnnexBranch file = do
branchChanged branchchange
runThreadState st $
whenM Annex.Branch.forceUpdate $
queueDeferredDownloads Later transferqueue dstatus
| "/synced/" `isInfixOf` file = runThreadState st $ do
mergecurrent =<< inRepo Git.Branch.current
| otherwise = noop