git-annex/Assistant/Threads/Pusher.hs
Joey Hess d71c65ca0a
add exporter thread to assistant
This is similar to the pusher thread, but a separate thread because git
pushes can be done in parallel with exports, and updating a big export
should not prevent other git pushes going out in the meantime.

The exportThread only runs at most every 30 seconds, since updating an
export is more expensive than pushing. This may need to be tuned.

Added a separate channel for export commits; the committer records a
commit in that channel.

Also, reconnectRemotes records a dummy commit, to make the exporter
thread wake up and make sure all exports are up-to-date. So,
connecting a drive with a directory special remote export will
immediately update it, and getting online will automatically
update S3 and WebDAV exports.

The transfer queue is not involved in exports. Instead, failed
exports are retried much like failed pushes.

This commit was sponsored by Ewen McNeill.
2017-09-20 15:29:13 -04:00

50 lines
1.7 KiB
Haskell

{- git-annex assistant git pushing thread
-
- Copyright 2012 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Assistant.Threads.Pusher where
import Assistant.Common
import Assistant.Commits
import Assistant.Pushes
import Assistant.DaemonStatus
import Assistant.Sync
import Utility.ThreadScheduler
import qualified Remote
import qualified Types.Remote as Remote
{- This thread retries pushes that failed before. -}
pushRetryThread :: NamedThread
pushRetryThread = namedThread "PushRetrier" $ runEvery (Seconds halfhour) <~> do
-- We already waited half an hour, now wait until there are failed
-- pushes to retry.
topush <- getFailedPushesBefore (fromIntegral halfhour)
=<< getAssistant failedPushMap
unless (null topush) $ do
debug ["retrying", show (length topush), "failed pushes"]
void $ pushToRemotes topush
where
halfhour = 1800
{- This thread pushes git commits out to remotes soon after they are made. -}
pushThread :: NamedThread
pushThread = namedThread "Pusher" $ runEvery (Seconds 2) <~> do
-- We already waited two seconds as a simple rate limiter.
-- Next, wait until at least one commit has been made
void getCommits
-- Now see if now's a good time to push.
void $ pushToRemotes =<< pushTargets
{- We want to avoid pushing to remotes that are marked readonly.
-
- Also, avoid pushing to local remotes we can easily tell are not available,
- to avoid ugly messages when a removable drive is not attached.
-}
pushTargets :: Assistant [Remote]
pushTargets = liftIO . filterM (Remote.checkAvailable True)
=<< candidates <$> getDaemonStatus
where
candidates = filter (not . Remote.readonly) . syncGitRemotes