{-# LANGUAGE CPP #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE ConstraintKinds #-}
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE FlexibleContexts #-}
{-# OPTIONS_GHC -fno-warn-orphans #-}
{-# OPTIONS_GHC -fno-warn-name-shadowing #-}
module Main where
import Control.Concurrent (threadDelay)
import Control.Monad
import Control.Monad.IO.Class (MonadIO(..))
import qualified Data.ByteString as B (readFile)
import Data.Foldable (foldlM)
import Data.Function (fix)
import Data.Map (Map)
import qualified Data.Map as Map
import Data.Maybe
import Data.Text (Text)
import qualified Data.Text as T (Text, pack, unpack)
import qualified Data.Text.Lazy as TL (Text, pack, unpack, toStrict, init)
import Data.Time
import Filesystem (getModified, isDirectory, isFile, canonicalizePath)
import Filesystem.Path.CurrentOS (FilePath, (</>), parent, null)
import Git hiding (Options)
import Git.Libgit2 (LgRepository, lgFactory, withLibGitDo)
import Git.Utils (treeBlobEntries)
import Options.Applicative
import Prelude hiding (FilePath, null)
import Shelly (toTextIgnore, fromText, silently, shelly, run)
import System.IO (stderr)
import System.Locale (defaultTimeLocale)
import System.Log.Formatter (tfLogFormatter)
import System.Log.Handler (setFormatter)
import System.Log.Handler.Simple (streamHandler)
import System.Log.Logger
toStrict :: TL.Text -> T.Text
toStrict = TL.toStrict
instance Read FilePath
data Options = Options
{ verbose :: Bool
, debug :: Bool
, gitDir :: String
, workingDir :: String
, interval :: Int
, resume :: Bool
}
options :: Parser Options
options = Options
<$> switch (short 'v' <> long "verbose" <> help "Display info")
<*> switch (short 'D' <> long "debug" <> help "Display debug")
<*> strOption
(long "git-dir" <> value ".git"
<> help "Git repository to store snapshots in (def: \".git\")")
<*> strOption (short 'd' <> long "work-dir" <> value ""
<> help "The working tree to snapshot (def: \".\")")
<*> option (short 'i' <> long "interval" <> value 60
<> help "Snapshot each N seconds")
<*> switch (short 'r' <> long "resume" <> value False
<> help "Resumes using last set of snapshots")
main :: IO ()
main = withLibGitDo $ execParser opts >>= doMain
where
opts = info (helper <*> options)
(fullDesc <> progDesc desc <> header hdr)
hdr = "git-monitor 1.0.0 - quickly snapshot working tree changes"
desc = "\nPassively snapshot working tree changes efficiently.\n\nThe intended usage is to run \"git monitor &\" in your project\ndirectory before you begin a hacking session.\n\nSnapshots are kept in refs/snapshots/refs/heads/$BRANCH"
doMain :: Options -> IO ()
doMain opts = do
-- Setup logging service if --verbose is used
when (verbose opts) $ initLogging (debug opts)
-- Ask Git for the user name and email in this repository
(userName,userEmail) <- shelly $ silently $
(,) <$> (TL.init <$> run "git" ["config", "user.name"])
<*> (TL.init <$> run "git" ["config", "user.email"])
let gDir = fromText (TL.pack (gitDir opts))
isDir <- isDirectory gDir
gd <- if isDir
then return gDir
else shelly $ silently $
fromText . TL.init <$> run "git" ["rev-parse", "--git-dir"]
let wDir = fromText (TL.pack (workingDir opts))
wd = if null wDir then parent gd else wDir
-- Make sure we're in a known branch, and if so, let it begin
forever $ withRepository lgFactory gd $ do
infoL $ "Saving snapshots under " ++ fileStr gd
infoL $ "Working tree: " ++ fileStr wd
ref <- lookupRef "HEAD"
void $ case ref of
Just (Reference _ (RefSymbolic name)) -> do
infoL $ "Tracking branch " ++ T.unpack name
start wd (toStrict userName) (toStrict userEmail) name
_ -> do
infoL "Cannot use git-monitor if no branch is checked out"
liftIO $ threadDelay (interval opts * 1000000)
where
initLogging debugMode = do
let level | debugMode = DEBUG
| verbose opts = INFO
| otherwise = NOTICE
h <- (`setFormatter` tfLogFormatter "%H:%M:%S" "$time - [$prio] $msg")
<$> streamHandler System.IO.stderr level
removeAllHandlers
updateGlobalLogger "git-monitor" (setLevel level)
updateGlobalLogger "git-monitor" (addHandler h)
start wd userName userEmail ref = do
let sref = "refs/snapshots/" <> ref
-- Usually we ignore any snapshot history from a prior invocation of
-- git-monitor, leaving those objects for git gc to cleanup; however,
-- if --resume, continue the snapshot history from where we last left
-- off. Note that if --resume is always used, this can end up
-- consuming a lot of disk space over time.
--
-- Also, it is useful to root the snapshot history at the current HEAD
-- commit. Note that it must be a Just value at this point, see
-- above.
scr <- if resume opts
then resolveRef sref
else return Nothing
scr' <- maybe (fromJust <$> resolveRef "HEAD") return scr
sc <- resolveCommitRef scr'
str <- resolveTreeRef (commitTree sc)
toid <- writeTree str
ft <- readFileTree' str wd (isNothing scr)
-- Begin the snapshotting process, which continues indefinitely until
-- the process is stopped. It is safe to cancel this process at any
-- time, typically using SIGINT (C-c) or even SIGKILL.
snapshotTree opts wd userName userEmail ref sref sc str toid ft
-- | 'snapshotTree' is the core workhorse of this utility. It periodically
-- checks the filesystem for changes to Git-tracked files, and snapshots
-- any changes that have occurred in them.
snapshotTree :: MonadGit m
=> Options -> FilePath
-> Text -> Text -> Text -> Text
-> Commit (LgRepository m)
-> Tree (LgRepository m) MutableTree
-> TreeOid (LgRepository m)
-> Map FilePath (FileEntry (LgRepository m))
-> LgRepository m ()
snapshotTree opts wd name email ref sref = fix $ \loop sc str toid ft -> do
-- Read the current working tree's state on disk
ft' <- readFileTree ref wd False
-- Prune files which have been removed since the last interval, and find
-- files which have been added or changed
Map.foldlWithKey' (\a p e -> a >> scanOldEntry str ft' p e) (return ()) ft
Map.foldlWithKey' (\a p e -> a >> scanNewEntry str ft p e) (return ()) ft'
-- If the snapshot tree changed, create a new commit to reflect it
toid' <- writeTree str
sc' <- if toid /= toid'
then do
now <- liftIO getZonedTime
let sig = Signature
{ signatureName = name
, signatureEmail = email
, signatureWhen = now
}
msg = "Snapshot at "
++ formatTime defaultTimeLocale "%F %T %Z" now
c <- createCommit [commitRef sc] (treeRef str)
sig sig (T.pack msg) (Just sref)
infoL $ "Commit "
++ (T.unpack . renderObjOid . commitOid $ c)
return c
else return sc
-- Wait a given number of seconds
liftIO $ threadDelay (interval opts * 1000000)
-- Rinse, wash, repeat.
ref' <- lookupRef "HEAD"
let curRef = case ref' of
Just (Reference _ (RefSymbolic ref'')) -> ref''
_ -> ""
if ref /= curRef
then infoL $ "Branch changed to " ++ T.unpack curRef
++ ", restarting"
else loop sc' str toid' ft'
where
scanOldEntry :: MonadGit m
=> Tree (LgRepository m) MutableTree
-> Map FilePath (FileEntry (LgRepository m))
-> FilePath
-> FileEntry (LgRepository m)
-> LgRepository m ()
scanOldEntry str ft fp _ = case Map.lookup fp ft of
Nothing -> do
infoL $ "Removed: " ++ fileStr fp
void $ unsafeMutateTree str $ dropEntry fp
_ -> return ()
scanNewEntry :: MonadGit m
=> Tree (LgRepository m) MutableTree
-> Map FilePath (FileEntry (LgRepository m))
-> FilePath
-> FileEntry (LgRepository m)
-> LgRepository m ()
scanNewEntry str ft fp (FileEntry mt (BlobEntry oid exe) _) =
case Map.lookup fp ft of
Nothing -> do
infoL $ "Added to snapshot: " ++ fileStr fp
void $ unsafeMutateTree str $ putBlob' fp oid exe
Just (FileEntry oldMt (BlobEntry oldOid oldExe) fileOid)
| oid /= oldOid || exe /= oldExe -> do
infoL $ "Changed: " ++ fileStr fp
void $ unsafeMutateTree str $ putBlob' fp oid exe
| mt /= oldMt || oid /= fileOid -> do
path <- fileStr <$>
liftIO (canonicalizePath (wd </> fp))
infoL $ "Changed: " ++ fileStr fp
contents <- liftIO $ B.readFile path
newOid <- createBlob (BlobString contents)
void $ unsafeMutateTree str $ putBlob' fp newOid exe
| otherwise -> return ()
_ -> return ()
scanNewEntry _str _ft _fp (FileEntry _mt _ _foid) = return ()
data FileEntry m = FileEntry
{ fileModTime :: UTCTime
, fileBlobEntry :: TreeEntry m
, fileChecksum :: BlobOid m
}
type FileTree m = Map FilePath (FileEntry m)
readFileTree :: MonadGit m
=> Text
-> FilePath
-> Bool
-> LgRepository m (FileTree (LgRepository m))
readFileTree ref wdir getHash = do
h <- resolveRef ref
case h of
Nothing -> pure Map.empty
Just h' -> do
tr <- resolveTreeRef . commitTree =<< resolveCommitRef h'
readFileTree' tr wdir getHash
readFileTree' :: MonadGit m
=> Tree (LgRepository m) MutableTree -> FilePath -> Bool
-> LgRepository m (FileTree (LgRepository m))
readFileTree' tr wdir getHash = do
blobs <- treeBlobEntries tr
foldlM (\m (fp,ent) -> do
fent <- readModTime wdir getHash fp ent
return $ maybe m (flip (Map.insert fp) m) fent)
Map.empty blobs
readModTime :: MonadGit m
=> FilePath
-> Bool
-> FilePath
-> TreeEntry (LgRepository m)
-> LgRepository m (Maybe (FileEntry (LgRepository m)))
readModTime wdir getHash fp ent = do
let path = wdir </> fp
debugL $ "Checking file: " ++ fileStr path
exists <- liftIO $ isFile path
if exists
then Just <$>
(FileEntry
<$> liftIO (getModified path)
<*> pure ent
<*> if getHash
then do contents <- liftIO $ B.readFile (fileStr path)
hashContents (BlobString contents)
else return (blobEntryOid ent))
else return Nothing
fileStr :: FilePath -> String
fileStr = TL.unpack . toTextIgnore
infoL :: (Repository m, MonadIO m) => String -> m ()
infoL = liftIO . infoM "git-monitor"
debugL :: (Repository m, MonadIO m) => String -> m ()
debugL = liftIO . debugM "git-monitor"
-- Main.hs (git-monitor) ends here