git-annex/Logs/Restage.hs

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{- git-annex restage log file
-
- Copyright 2022 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU AGPL version 3 or higher.
-}
{-# LANGUAGE OverloadedStrings #-}
module Logs.Restage where
import Annex.Common
import Git.FilePath
import Logs.File
add restage log When pointer files need to be restaged, they're first written to the log, and then when the restage operation runs, it reads the log. This way, if the git-annex process is interrupted before it can do the restaging, a later git-annex process can do it. Currently, this lets a git-annex get/drop command be interrupted and then re-ran, and as long as it gets/drops additional files, it will clean up after the interrupted command. But more changes are needed to make it easier to restage after an interrupted process. Kept using the git queue to run the restage action, even though the list of files that it builds up for that action is not actually used by the action. This could perhaps be simplified to make restaging a cleanup action that gets registered, rather than using the git queue for it. But I wasn't sure if that would cause visible behavior changes, when eg dropping a large number of files, currently the git queue flushes periodically, and so it restages incrementally, rather than all at the end. In restagePointerFiles, it reads the restage log twice, once to get the number of files and size, and a second time to process it. This seemed better than reading the whole file into memory, since potentially a huge number of files could be in there. Probably the OS will cache the file in memory and there will not be much performance impact. It might be better to keep running tallies in another file though. But updating that atomically with the log seems hard. Also note that it's possible for calcRestageLog to see a different file than streamRestageLog does. More files may be added to the log in between. That is ok, it will only cause the filterprocessfaster heuristic to operate with slightly out of date information, so it may make the wrong choice for the files that got added and be a little slower than ideal. Sponsored-by: Dartmouth College's DANDI project
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import Utility.InodeCache
add restage log When pointer files need to be restaged, they're first written to the log, and then when the restage operation runs, it reads the log. This way, if the git-annex process is interrupted before it can do the restaging, a later git-annex process can do it. Currently, this lets a git-annex get/drop command be interrupted and then re-ran, and as long as it gets/drops additional files, it will clean up after the interrupted command. But more changes are needed to make it easier to restage after an interrupted process. Kept using the git queue to run the restage action, even though the list of files that it builds up for that action is not actually used by the action. This could perhaps be simplified to make restaging a cleanup action that gets registered, rather than using the git queue for it. But I wasn't sure if that would cause visible behavior changes, when eg dropping a large number of files, currently the git queue flushes periodically, and so it restages incrementally, rather than all at the end. In restagePointerFiles, it reads the restage log twice, once to get the number of files and size, and a second time to process it. This seemed better than reading the whole file into memory, since potentially a huge number of files could be in there. Probably the OS will cache the file in memory and there will not be much performance impact. It might be better to keep running tallies in another file though. But updating that atomically with the log seems hard. Also note that it's possible for calcRestageLog to see a different file than streamRestageLog does. More files may be added to the log in between. That is ok, it will only cause the filterprocessfaster heuristic to operate with slightly out of date information, so it may make the wrong choice for the files that got added and be a little slower than ideal. Sponsored-by: Dartmouth College's DANDI project
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import qualified Data.ByteString as S
import qualified Data.ByteString.Lazy as L
-- | Log a file whose pointer needs to be restaged in git.
-- The content of the file may not be a pointer, if it is populated with
-- the annex content. The InodeCache is used to verify that the file
-- still contains the content, and it's still safe to restage its pointer.
writeRestageLog :: TopFilePath -> InodeCache -> Annex ()
writeRestageLog f ic = do
logf <- fromRepo gitAnnexRestageLog
lckf <- fromRepo gitAnnexRestageLock
add restage log When pointer files need to be restaged, they're first written to the log, and then when the restage operation runs, it reads the log. This way, if the git-annex process is interrupted before it can do the restaging, a later git-annex process can do it. Currently, this lets a git-annex get/drop command be interrupted and then re-ran, and as long as it gets/drops additional files, it will clean up after the interrupted command. But more changes are needed to make it easier to restage after an interrupted process. Kept using the git queue to run the restage action, even though the list of files that it builds up for that action is not actually used by the action. This could perhaps be simplified to make restaging a cleanup action that gets registered, rather than using the git queue for it. But I wasn't sure if that would cause visible behavior changes, when eg dropping a large number of files, currently the git queue flushes periodically, and so it restages incrementally, rather than all at the end. In restagePointerFiles, it reads the restage log twice, once to get the number of files and size, and a second time to process it. This seemed better than reading the whole file into memory, since potentially a huge number of files could be in there. Probably the OS will cache the file in memory and there will not be much performance impact. It might be better to keep running tallies in another file though. But updating that atomically with the log seems hard. Also note that it's possible for calcRestageLog to see a different file than streamRestageLog does. More files may be added to the log in between. That is ok, it will only cause the filterprocessfaster heuristic to operate with slightly out of date information, so it may make the wrong choice for the files that got added and be a little slower than ideal. Sponsored-by: Dartmouth College's DANDI project
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appendLogFile logf lckf $ L.fromStrict $ formatRestageLog f ic
-- | Streams the content of the restage log, and then empties the log at
-- the end.
--
add restage log When pointer files need to be restaged, they're first written to the log, and then when the restage operation runs, it reads the log. This way, if the git-annex process is interrupted before it can do the restaging, a later git-annex process can do it. Currently, this lets a git-annex get/drop command be interrupted and then re-ran, and as long as it gets/drops additional files, it will clean up after the interrupted command. But more changes are needed to make it easier to restage after an interrupted process. Kept using the git queue to run the restage action, even though the list of files that it builds up for that action is not actually used by the action. This could perhaps be simplified to make restaging a cleanup action that gets registered, rather than using the git queue for it. But I wasn't sure if that would cause visible behavior changes, when eg dropping a large number of files, currently the git queue flushes periodically, and so it restages incrementally, rather than all at the end. In restagePointerFiles, it reads the restage log twice, once to get the number of files and size, and a second time to process it. This seemed better than reading the whole file into memory, since potentially a huge number of files could be in there. Probably the OS will cache the file in memory and there will not be much performance impact. It might be better to keep running tallies in another file though. But updating that atomically with the log seems hard. Also note that it's possible for calcRestageLog to see a different file than streamRestageLog does. More files may be added to the log in between. That is ok, it will only cause the filterprocessfaster heuristic to operate with slightly out of date information, so it may make the wrong choice for the files that got added and be a little slower than ideal. Sponsored-by: Dartmouth College's DANDI project
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-- If the processor or finalizer is interrupted or throws an exception,
-- the log file is left unchanged.
--
-- Locking is used to prevent new items being added to the log while this
-- is running.
add restage log When pointer files need to be restaged, they're first written to the log, and then when the restage operation runs, it reads the log. This way, if the git-annex process is interrupted before it can do the restaging, a later git-annex process can do it. Currently, this lets a git-annex get/drop command be interrupted and then re-ran, and as long as it gets/drops additional files, it will clean up after the interrupted command. But more changes are needed to make it easier to restage after an interrupted process. Kept using the git queue to run the restage action, even though the list of files that it builds up for that action is not actually used by the action. This could perhaps be simplified to make restaging a cleanup action that gets registered, rather than using the git queue for it. But I wasn't sure if that would cause visible behavior changes, when eg dropping a large number of files, currently the git queue flushes periodically, and so it restages incrementally, rather than all at the end. In restagePointerFiles, it reads the restage log twice, once to get the number of files and size, and a second time to process it. This seemed better than reading the whole file into memory, since potentially a huge number of files could be in there. Probably the OS will cache the file in memory and there will not be much performance impact. It might be better to keep running tallies in another file though. But updating that atomically with the log seems hard. Also note that it's possible for calcRestageLog to see a different file than streamRestageLog does. More files may be added to the log in between. That is ok, it will only cause the filterprocessfaster heuristic to operate with slightly out of date information, so it may make the wrong choice for the files that got added and be a little slower than ideal. Sponsored-by: Dartmouth College's DANDI project
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streamRestageLog :: Annex () -> (TopFilePath -> InodeCache -> Annex ()) -> Annex ()
streamRestageLog finalizer processor = do
logf <- fromRepo gitAnnexRestageLog
lckf <- fromRepo gitAnnexRestageLock
add restage log When pointer files need to be restaged, they're first written to the log, and then when the restage operation runs, it reads the log. This way, if the git-annex process is interrupted before it can do the restaging, a later git-annex process can do it. Currently, this lets a git-annex get/drop command be interrupted and then re-ran, and as long as it gets/drops additional files, it will clean up after the interrupted command. But more changes are needed to make it easier to restage after an interrupted process. Kept using the git queue to run the restage action, even though the list of files that it builds up for that action is not actually used by the action. This could perhaps be simplified to make restaging a cleanup action that gets registered, rather than using the git queue for it. But I wasn't sure if that would cause visible behavior changes, when eg dropping a large number of files, currently the git queue flushes periodically, and so it restages incrementally, rather than all at the end. In restagePointerFiles, it reads the restage log twice, once to get the number of files and size, and a second time to process it. This seemed better than reading the whole file into memory, since potentially a huge number of files could be in there. Probably the OS will cache the file in memory and there will not be much performance impact. It might be better to keep running tallies in another file though. But updating that atomically with the log seems hard. Also note that it's possible for calcRestageLog to see a different file than streamRestageLog does. More files may be added to the log in between. That is ok, it will only cause the filterprocessfaster heuristic to operate with slightly out of date information, so it may make the wrong choice for the files that got added and be a little slower than ideal. Sponsored-by: Dartmouth College's DANDI project
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streamLogFile (fromRawFilePath logf) lckf finalizer $ \l ->
case parseRestageLog l of
Just (f, ic) -> processor f ic
Nothing -> noop
add restage log When pointer files need to be restaged, they're first written to the log, and then when the restage operation runs, it reads the log. This way, if the git-annex process is interrupted before it can do the restaging, a later git-annex process can do it. Currently, this lets a git-annex get/drop command be interrupted and then re-ran, and as long as it gets/drops additional files, it will clean up after the interrupted command. But more changes are needed to make it easier to restage after an interrupted process. Kept using the git queue to run the restage action, even though the list of files that it builds up for that action is not actually used by the action. This could perhaps be simplified to make restaging a cleanup action that gets registered, rather than using the git queue for it. But I wasn't sure if that would cause visible behavior changes, when eg dropping a large number of files, currently the git queue flushes periodically, and so it restages incrementally, rather than all at the end. In restagePointerFiles, it reads the restage log twice, once to get the number of files and size, and a second time to process it. This seemed better than reading the whole file into memory, since potentially a huge number of files could be in there. Probably the OS will cache the file in memory and there will not be much performance impact. It might be better to keep running tallies in another file though. But updating that atomically with the log seems hard. Also note that it's possible for calcRestageLog to see a different file than streamRestageLog does. More files may be added to the log in between. That is ok, it will only cause the filterprocessfaster heuristic to operate with slightly out of date information, so it may make the wrong choice for the files that got added and be a little slower than ideal. Sponsored-by: Dartmouth College's DANDI project
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calcRestageLog :: t -> ((TopFilePath, InodeCache) -> t -> t) -> Annex t
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calcRestageLog start update = do
add restage log When pointer files need to be restaged, they're first written to the log, and then when the restage operation runs, it reads the log. This way, if the git-annex process is interrupted before it can do the restaging, a later git-annex process can do it. Currently, this lets a git-annex get/drop command be interrupted and then re-ran, and as long as it gets/drops additional files, it will clean up after the interrupted command. But more changes are needed to make it easier to restage after an interrupted process. Kept using the git queue to run the restage action, even though the list of files that it builds up for that action is not actually used by the action. This could perhaps be simplified to make restaging a cleanup action that gets registered, rather than using the git queue for it. But I wasn't sure if that would cause visible behavior changes, when eg dropping a large number of files, currently the git queue flushes periodically, and so it restages incrementally, rather than all at the end. In restagePointerFiles, it reads the restage log twice, once to get the number of files and size, and a second time to process it. This seemed better than reading the whole file into memory, since potentially a huge number of files could be in there. Probably the OS will cache the file in memory and there will not be much performance impact. It might be better to keep running tallies in another file though. But updating that atomically with the log seems hard. Also note that it's possible for calcRestageLog to see a different file than streamRestageLog does. More files may be added to the log in between. That is ok, it will only cause the filterprocessfaster heuristic to operate with slightly out of date information, so it may make the wrong choice for the files that got added and be a little slower than ideal. Sponsored-by: Dartmouth College's DANDI project
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logf <- fromRepo gitAnnexRestageLog
lckf <- fromRepo gitAnnexRestageLock
calcLogFile logf lckf start $ \l v ->
add restage log When pointer files need to be restaged, they're first written to the log, and then when the restage operation runs, it reads the log. This way, if the git-annex process is interrupted before it can do the restaging, a later git-annex process can do it. Currently, this lets a git-annex get/drop command be interrupted and then re-ran, and as long as it gets/drops additional files, it will clean up after the interrupted command. But more changes are needed to make it easier to restage after an interrupted process. Kept using the git queue to run the restage action, even though the list of files that it builds up for that action is not actually used by the action. This could perhaps be simplified to make restaging a cleanup action that gets registered, rather than using the git queue for it. But I wasn't sure if that would cause visible behavior changes, when eg dropping a large number of files, currently the git queue flushes periodically, and so it restages incrementally, rather than all at the end. In restagePointerFiles, it reads the restage log twice, once to get the number of files and size, and a second time to process it. This seemed better than reading the whole file into memory, since potentially a huge number of files could be in there. Probably the OS will cache the file in memory and there will not be much performance impact. It might be better to keep running tallies in another file though. But updating that atomically with the log seems hard. Also note that it's possible for calcRestageLog to see a different file than streamRestageLog does. More files may be added to the log in between. That is ok, it will only cause the filterprocessfaster heuristic to operate with slightly out of date information, so it may make the wrong choice for the files that got added and be a little slower than ideal. Sponsored-by: Dartmouth College's DANDI project
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case parseRestageLog (decodeBL l) of
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Just pl -> update pl v
add restage log When pointer files need to be restaged, they're first written to the log, and then when the restage operation runs, it reads the log. This way, if the git-annex process is interrupted before it can do the restaging, a later git-annex process can do it. Currently, this lets a git-annex get/drop command be interrupted and then re-ran, and as long as it gets/drops additional files, it will clean up after the interrupted command. But more changes are needed to make it easier to restage after an interrupted process. Kept using the git queue to run the restage action, even though the list of files that it builds up for that action is not actually used by the action. This could perhaps be simplified to make restaging a cleanup action that gets registered, rather than using the git queue for it. But I wasn't sure if that would cause visible behavior changes, when eg dropping a large number of files, currently the git queue flushes periodically, and so it restages incrementally, rather than all at the end. In restagePointerFiles, it reads the restage log twice, once to get the number of files and size, and a second time to process it. This seemed better than reading the whole file into memory, since potentially a huge number of files could be in there. Probably the OS will cache the file in memory and there will not be much performance impact. It might be better to keep running tallies in another file though. But updating that atomically with the log seems hard. Also note that it's possible for calcRestageLog to see a different file than streamRestageLog does. More files may be added to the log in between. That is ok, it will only cause the filterprocessfaster heuristic to operate with slightly out of date information, so it may make the wrong choice for the files that got added and be a little slower than ideal. Sponsored-by: Dartmouth College's DANDI project
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Nothing -> v
formatRestageLog :: TopFilePath -> InodeCache -> S.ByteString
formatRestageLog f ic = encodeBS (showInodeCache ic) <> ":" <> getTopFilePath f
parseRestageLog :: String -> Maybe (TopFilePath, InodeCache)
parseRestageLog l =
let (ics, f) = separate (== ':') l
in do
ic <- readInodeCache ics
return (asTopFilePath (toRawFilePath f), ic)