{-# LANGUAGE BangPatterns #-}
{-# LANGUAGE ConstraintKinds #-}
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE TypeFamilies #-}
{-# OPTIONS_GHC -fno-warn-orphans #-}
{-# OPTIONS_GHC -fno-warn-name-shadowing #-}
module Main where
import Control.Concurrent (threadDelay)
import Control.Logging
import Control.Monad
import Control.Monad.IO.Class (MonadIO(..))
import Control.Monad.Logger
import Control.Monad.Trans.Class
import qualified Data.ByteString as B (readFile)
import qualified Data.ByteString.Char8 as B8
import Data.Function (fix)
import Data.HashMap.Strict (HashMap)
import qualified Data.HashMap.Strict as Map
import Data.Maybe
import Data.Tagged
import Data.Text (pack)
import qualified Data.Text as T
import qualified Data.Text.Encoding as T
import Data.Time
import Git hiding (Options)
import Git.Tree.Working
import Git.Libgit2 (MonadLg, LgRepo, lgFactoryLogger)
import Options.Applicative
import Prelude hiding (log)
import Shelly (silently, shelly, run)
import System.Directory
import System.FilePath.Posix
import System.Locale (defaultTimeLocale)
data Options = Options
{ optQuiet :: Bool
, optVerbose :: Bool
, optDebug :: Bool
, optGitDir :: FilePath
, optWorkingDir :: FilePath
, optInterval :: Int
, optResume :: Bool
}
options :: Parser Options
options = Options
<$> switch (short 'q' <> long "quiet" <> help "Do not display progress")
<*> switch (short 'v' <> long "verbose" <> help "Display more info")
<*> switch (short 'D' <> long "debug" <> help "Display debug")
<*> strOption
(long "git-dir" <> value ".git"
<> help "Git repository to store snapshots in (def: \".git\")")
<*> strOption (short 'd' <> long "work-dir" <> value ""
<> help "The working tree to snapshot (def: \".\")")
<*> option auto (short 'i' <> long "interval" <> value 60
<> help "Snapshot each N seconds")
<*> switch (short 'r' <> long "resume"
<> help "Resumes using last set of snapshots")
main :: IO ()
main = execParser opts >>= withStdoutLogging . doMain
where
opts = info (helper <*> options)
(fullDesc <> progDesc desc <> header hdr)
hdr = "git-monitor 3.1.1.2 - quickly snapshot working tree changes"
desc = "\nPassively snapshot working tree changes efficiently.\n\nThe intended usage is to run \"git monitor &\" in your project\ndirectory before you begin a hacking session.\n\nSnapshots are kept in refs/snapshots/refs/heads/$BRANCH"
doMain :: Options -> IO ()
doMain opts = do
-- Setup logging service if --verbose is used
setLogTimeFormat "%H:%M:%S"
setLogLevel $ if optQuiet opts
then LevelError
else if optDebug opts
then LevelDebug
else LevelInfo
-- Ask Git for the user name and email in this repository
(userName,userEmail) <- shelly $ silently $
(,) <$> (T.init <$> run "git" ["config", "user.name"])
<*> (T.init <$> run "git" ["config", "user.email"])
let gDir = optGitDir opts
isDir <- doesDirectoryExist gDir
gd <- if isDir
then return gDir
else shelly $ silently $
T.unpack . T.init <$> run "git" ["rev-parse", "--git-dir"]
let wDir = optWorkingDir opts
wd = if null wDir then takeDirectory gd else wDir
-- Make sure we're in a known branch, and if so, let it begin
forever $ withRepository lgFactoryLogger gd $ do
log' $ pack $ "Saving snapshots under " ++ gd
log' $ pack $ "Working tree: " ++ wd
ref <- lookupReference "HEAD"
case ref of
Just (RefSymbolic name) -> do
log' $ "Tracking branch " <> name
void $ start wd userName userEmail name
_ -> do
log' "Cannot use git-monitor if no branch is checked out"
liftIO $ threadDelay (optInterval opts * 1000000)
where
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 optResume opts
then resolveReference sref
else return Nothing
scr' <- maybe (resolveReference "HEAD") (return . Just) scr
case scr' of
Nothing -> errorL "Failed to lookup reference"
Just r -> do
sc <- lookupCommit (Tagged r)
let toid = commitTree sc
tree <- lookupTree toid
ft <- readFileTree' tree 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.
mutateTreeOid toid $
snapshotTree opts wd userName userEmail ref sref sc 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 LgRepo m, MonadLg m)
=> Options
-> FilePath
-> CommitAuthor
-> CommitEmail
-> RefName
-> RefName
-> Commit LgRepo
-> TreeOid LgRepo
-> HashMap TreeFilePath (FileEntry LgRepo)
-> TreeT LgRepo m ()
snapshotTree opts wd name email ref sref = fix $ \loop sc toid ft -> do
-- Read the current working tree's state on disk
ft' <- lift $ 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 ft' p e) (return ()) ft
Map.foldlWithKey' (\a p e -> a >> scanNewEntry ft p e) (return ()) ft'
toid' <- currentTreeOid
-- If the snapshot tree changed, create a new commit to reflect it
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 <- lift $ createCommit [commitOid sc] toid'
sig sig (T.pack msg) (Just sref)
lift $ log' $ "Commit " <> (renderObjOid . commitOid $ c)
return c
else return sc
-- Wait a given number of seconds
liftIO $ threadDelay (optInterval opts * 1000000)
-- Rinse, wash, repeat.
ref' <- lift $ lookupReference "HEAD"
let curRef = case ref' of Just (RefSymbolic ref'') -> ref''; _ -> ""
if ref /= curRef
then lift $ log' $ "Branch changed to " <> curRef <> ", restarting"
else loop sc' toid' ft'
where
scanOldEntry :: (MonadGit LgRepo m, MonadLg m)
=> HashMap TreeFilePath (FileEntry LgRepo)
-> TreeFilePath
-> FileEntry LgRepo
-> TreeT LgRepo m ()
scanOldEntry ft fp _ = case Map.lookup fp ft of
Nothing -> do
log' $ "Removed: " <> T.decodeUtf8 fp
dropEntry fp
_ -> return ()
scanNewEntry :: (MonadGit LgRepo m, MonadLg m)
=> HashMap TreeFilePath (FileEntry LgRepo)
-> TreeFilePath
-> FileEntry LgRepo
-> TreeT LgRepo m ()
scanNewEntry ft fp (FileEntry mt oid kind _) =
case Map.lookup fp ft of
Nothing -> do
log' $ "Added to snapshot: " <> T.decodeUtf8 fp
putBlob' fp oid kind
Just (FileEntry oldMt oldOid oldKind fileOid)
| oid /= oldOid || kind /= oldKind -> do
log' $ "Changed: " <> T.decodeUtf8 fp
putBlob' fp oid kind
| mt /= oldMt || oid /= fileOid -> do
log' $ "Changed: " <> T.decodeUtf8 fp
path <- liftIO $ canonicalizePath (wd </> B8.unpack fp)
contents <- liftIO $ B.readFile path
newOid <- lift $ createBlob (BlobString contents)
putBlob' fp newOid kind
| otherwise -> return ()
-- Main.hs (git-monitor) ends here