Göran Krampe / Blimp

import md5, os, osproc, parseopt2, strutils, parsecfg, streams, lapp, subexes

# blimp is a little utility program for handling large files
# in git repositories. Its inspired by git-fat and s3annex
# but doesn't rely on S3 for storage - it uses rsync like git-fat.
# It is a single binary without any dependencies.
#
# Manual use:
#
# Use "blimp d mybigfile" to deflate it before commit.
# Use "blimp i mybigfile" to inflate it back to original size.
#
# When deflated the file only has:
#   "hash:" <filename> + <an md5sum>
# ...inside it.
#
# The file is copied over to a local dir:
#  <blimpstore>/<filename>-<md5sum>
#
# Configuration is in these locations in order:
#
#   ./.blimp.conf
#   <gitroot>/.blimp.conf
#   ~/<blimpstore>/.blimp.conf
#   ~/.blimp.conf
#
# This way you can have settings per directory, per git clone,
# per store and per user. A default blimpstore with a commented .blimp.conf
# is created in ~/blimpstore if you run blimp and no .blimp.conf is found.

const 
  versionMajor* = 0
  versionMinor* = 2
  versionPatch* = 1
  versionAsString* = $versionMajor & "." & $versionMinor & "." & $versionPatch

var
  blimpStore, remoteBlimpStore, uploadCommandFormat, downloadCommandFormat, deleteCommandFormat, rsyncPassword, blimpVersion: string = nil
  homeDir, currentDir, gitRootDir: string
  verbose, stdio: bool
  stdinContent: string = nil

let
  defaultConfig = """
[rsync]
# Set your local blimpstore directory. You can use %home%, %cwd% and %gitroot% in paths, works cross platform.
# Example:
#   # Place it inside the git clone
#   blimpstore = "%gitroot%/.git/blimpstore"
#   # Place it in current working directory (not very useful)
#   blimpstore = "%cwd%/blimpstore"
#
# Default:
#   # Place it in the users home directory
#   blimpstore = "%home%/blimpstore"

# Set this to your remote rsync location
remote = "blimpuser@some-rsync-server.com::blimpstore"
# Set this to your rsync password, it will be written out as a password-file called .blimp.pass on every rsync.
password = "some-good-rsync-password-for-blimpuser"

# The following three formats should not need editing.
# $1 is the blimp filename, $2 is remote location and $3 is the local blimpstore directory set above.
# NOTE: The password-file .blimp.pass will be created by blimp on every command, do not remove that option.
upload = "rsync --password-file $3/.blimp.pass -avzP $3/$1 $2/"
download = "rsync --password-file $3/.blimp.pass -avzP $2/$1 $3/"
# This deletes a single file from destination, that is already deleted in source. Yeah... insane! But it works.
delete = "rsync --password-file $3/.blimp.pass -dv --delete --existing --ignore-existing --include '$1' --exclude '*' $3/ $2"

[blimp]
# Minimal version, otherwise stop
# version = 0.2 
"""

# Find git root dir or nil
proc gitRoot(): string =
  try:
    let tup = execCmdEx("git rev-parse --show-toplevel")
    if tup[1] == 0:
      result = strip(tup[0])
    else:
      result = nil
  except:
    result = nil

# Simple expansion of %home%, %cwd% and %gitroot%
proc expandDirs(templ: string): string =
  result = templ.replace("%home%", homeDir)
  result = result.replace("%cwd%", currentDir)
  if result.contains("%gitroot%"):
    if gitRootDir.isNil: quit("Not in a git clone, can not expand %gitroot% in '" & templ & "'") 
    result = result.replace("%gitroot%", gitRootDir)

# Load a blimp.conf file
proc parseConfFile(filename: string) =
  var f = newFileStream(filename, fmRead)
  if f != nil:
    if verbose: echo "Reading config: " & filename
    var p: CfgParser
    
    open(p, f, filename)
    while true:
      var e = next(p)
      case e.kind
      of cfgEof: 
        break
      of cfgSectionStart:
        continue # Ignore
      of cfgKeyValuePair:
        case e.key
        of "blimpstore":
          if blimpStore.isNil: blimpStore = expandDirs(e.value)
        of "remote":
          if remoteBlimpStore.isNil: remoteBlimpStore = expandDirs(e.value)
        of "password":
          if rsyncPassword.isNil: rsyncPassword = e.value
        of "upload":
          if uploadCommandFormat.isNil: uploadCommandFormat = expandDirs(e.value)
        of "download":
          if downloadCommandFormat.isNil: downloadCommandFormat = expandDirs(e.value)
        of "delete":
          if deleteCommandFormat.isNil: deleteCommandFormat = expandDirs(e.value)
        of "version":
          if blimpVersion.isNil: blimpVersion = e.value
        else:
          quit("Unknown configuration: " & e.key)
      of cfgOption:
        quit("Unknown configuration: " & e.key)
      of cfgError:
        quit("Parsing " & filename & ": " & e.msg)
    close(p)

# Trivial helper to enable verbose
proc run(cmd: string): auto =
  if verbose: echo(cmd)
  execCmd(cmd)

# Every rsync command, make sure we have a password file
proc rsyncRun(cmd: string): auto =
  if not rsyncPassword.isNil:
    writeFile(blimpStore / ".blimp.pass", rsyncPassword)
    if execCmd("chmod 600 " & blimpStore / ".blimp.pass") != 0:
      quit("Failed to chmod 600 " & blimpStore / ".blimp.pass")
  run(cmd)

# Upload a file to the remote master blimpStore
proc uploadFile(blimpFilename: string) =
  if remoteBlimpStore.isNil:
    echo("Remote blimpstore not set in configuration file, skipping uploading content:\n\t" & blimpFilename)
    return
  let errorCode = rsyncRun(format(uploadCommandFormat, blimpFilename, remoteBlimpStore, blimpStore))
  if errorCode != 0:
    quit("Something went wrong uploading " & blimpFilename & " to " & remoteBlimpStore, 2)
  
# Download a file to the remote master blimpStore
proc downloadFile(blimpFilename: string) =
  if remoteBlimpStore.isNil:
    quit("Remote blimpstore not set in configuration file, can not download content:\n\t" & blimpFilename)
  let errorCode = rsyncRun(format(downloadCommandFormat, blimpFilename, remoteBlimpStore, blimpStore))
  if errorCode != 0:
    quit("Something went wrong downloading " & blimpFilename & " from " & remoteBlimpStore, 3)

# Delete a file from the remote master blimpStore
proc remoteDeleteFile(blimpFilename: string) =
  if remoteBlimpStore.isNil:
    return
  let errorCode = rsyncRun(format(deleteCommandFormat, blimpFilename, remoteBlimpStore, blimpStore))
  if errorCode != 0:
    quit("Something went wrong deleting " & blimpFilename & " from " & remoteBlimpStore, 3)

# Copy content to blimpStore, no upload yet.
proc copyToBlimpStore(filename, blimpFilename: string) =
  if not existsFile(blimpStore / blimpFilename):
    if stdio:
      try:
        writeFile(blimpStore / blimpFilename, stdinContent)
      except:
        quit("Failed writing file: " & blimpStore / blimpFilename & " from stdin", 1)
    else:
      copyFile(filename, blimpStore / blimpFilename)
      uploadFile(blimpFilename)

# Copy content from blimpStore, and downloading first if needed
proc copyFromBlimpStore(blimpFilename, filename: string) =
  if not existsFile(blimpStore / blimpFilename):
    downloadFile(blimpFilename)
  if stdio:
    try:
      var content = readFile(blimpStore / blimpFilename)
      write(stdout, content)
    except:
      quit("Failed reading file: " & blimpStore / blimpFilename & " to stdout", 1)
  else:
    copyFile(blimpStore / blimpFilename, filename)

# Delete from blimpStore and remote.
proc deleteFromBlimpStore(blimpFilename, filename: string) =
  if existsFile(blimpStore / blimpFilename):
    removeFile(blimpStore / blimpFilename)
  remoteDeleteFile(blimpFilename)

proc blimpFileNameFromString(line: string): string =
  let hashline = split(strip(line), {':'})
  if hashline[0] == "hash":
    result = hashline[1]
  else:
    result = nil

# Pick out blimpFilename (filename & "-" & hash)
proc blimpFileName(filename: string): string =
  if stdio:
    blimpFileNameFromString(stdinContent)
  else:
    var hashfile: File
    if not open(hashfile, filename):
      quit("Failed opening file: " & filename, 4)
    blimpFileNameFromString(string(readLine(hashfile)))  

# Get hash and compute blimpFilename
proc computeBlimpFilename(filename: string): string =
  var content: string
  try:
    content = readFile(filename)
  except:
    quit("Failed opening file: " & filename, 1)
  let hash = getMD5(content)
  result = filename & "-" & hash
 
# Copy original file to blimpStore and replace with hash stub in git.
proc deflate(filename: string) =
  if verbose: echo "Deflating " & filename
  var blimpFilename = blimpFilename(filename)
  if not blimpFilename.isNil:
    echo("\t" & filename & " is already deflated, skipping.")
  else:
    blimpFilename = computeBlimpFilename(filename)
    copyToBlimpStore(filename, blimpFilename)
    if stdio:
      write(stdout, "hash:" & blimpFilename)
    else:
      writeFile(filename, "hash:" & blimpFilename)
    if verbose: echo("\t" & filename & " deflated.")

# Parse out hash from hash stub and copy back original content from blimpStore.
proc inflate(filename: string) =
  if verbose: echo "Inflating " & filename
  let blimpFilename = blimpFilename(filename)
  if blimpFilename.isNil:
    echo("\t" & filename & " is not deflated, skipping.")
  else:
    copyFromBlimpStore(blimpfilename, filename)
    if verbose: echo("\t" & filename & " inflated.")

# Inflates file first (if deflated) and then removes current content for it,
# both locally and in remote.
proc remove(filename: string) =
  var blimpFilename = blimpFilename(filename)
  if not blimpFilename.isNil:
    copyFromBlimpStore(blimpfilename, filename)
  else:
    blimpFilename = computeBlimpFilename(filename)
  deleteFromBlimpStore(blimpfilename, filename)
  echo("\t" & filename & " content removed from blimpstore locally and remotely.")


proc setupBlimpStore() =
  try:
    if not existsDir(blimpStore):
      createDir(blimpStore)
  except:
    quit("Could not create " & blimpStore & " directory.", 1)

  try:
    if not existsFile(blimpStore / ".blimp.conf"):
      writeFile(blimpStore / ".blimp.conf", defaultConfig)
  except:
    quit("Could not create .blimp.conf config file in " & blimpStore & " directory.", 1)

proc `$`(x: string): string =
  if x.isNil: "nil" else: x

proc dumpConfig() =
  echo "\nDump of configuration:"
  echo "\tblimpStore: " & blimpStore
  echo "\tremoteBlimpStore: " & remoteBlimpStore
  echo "\tuploadCommandFormat: " & uploadCommandFormat
  echo "\tdownloadCommandFormat: " & downloadCommandFormat
  echo "\tdeleteCommandFormat: " & deleteCommandFormat
  echo "\trsyncPassword: " & $rsyncPassword
  echo "\tblimpVersion: " & $blimpVersion
  echo "\n"

let help = """
  blimp [options] <command> <filenames...>
    -h,--help                Show this
    --version                Show version of blimp
    -v,--verbose             Verbosity, only works without -s
    -s,--stdio               If given, use stdin/stdout for content.
    <command>   (string)     (d)eflate, (i)nflate, remove
    <filenames> (string...)        One or more filepaths to inflate/deflate

  blimp is a little utility program for handling large files
  in git repositories. Its inspired by git-fat and s3annex
  but doesn't rely on S3 for storage - it uses rsync like git-fat.
  It is a single binary without any dependencies.

  Manual use:

  Use "blimp d mybigfile" to deflate it before commit.
  Use "blimp i mybigfile" to inflate it back to original size.

  When deflated the file only has:
    "hash:" <filename> "-" <md5sum>
  ...inside it.

  Deflate is run before you add the big file to the index for committing.
  Deflate will replace the file contents with a hash, and copy the
  real content to your local blimpstore:
  
    "blimpstore"/<filename>-<md5sum>

  ...and if configured also upload it to "remote", using rsync.

  Configuration is in these locations in order:
 
    ./.blimp.conf
    "gitroot"/.blimp.conf
    ~/<blimpstore>/.blimp.conf
    ~/.blimp.conf

  This way you can have settings per directory, per git clone,
  per store and per user. A default blimpstore with a commented .blimp.conf
  is created in ~/blimpstore if you run blimp and no .blimp.conf is found.

  Edit ~/blimpstore/.blimp.conf (or in another location) and set a proper
  remote and the proper rsync password. This ensures that its also properly
  synced with a master rsync repository that is typically shared.

  Inflate will bring back the original content by copying from
  your local blimpstore, and if its not there, first downloading from the remote.
  Use this whenever you need to work/edit the big file - in order to get
  its real content.

  The filenames given are all processed. If -s is used content is processed via
  stdin/stdout and only one filename can be passed. This is used when running blimp
  via a git filter (smudge/clean).

  The remove command (no single character shortcut) will remove the file(s) content
  both from the local blimpstore and from the remote. This only removes
  the current content version, not older versions. The file itself is first
  inflated, if needed, and not deleted. This only "unblimps" the file.
"""

################################ main #####################################
# Set some dirs
homeDir = getHomeDir()
homeDir = homeDir[0.. -2] # Not sure why it keeps a trailing "/" on Linux
currentDir = getCurrentDir()
gitRootDir = gitRoot()

# Using lapp to get args, on parsing failure this will show usage automatically
var args = parse(help)
verbose = args["verbose"].asBool
stdio = args["stdio"].asBool

# Can't do verbose with -s, that messes up stdout,
# read in all of stdin once and for all
if stdio:
  verbose = false
  try:
    stdinContent = readAll(stdin)
    close(stdin)
  except:
    quit("Failed reading stdin", 1)


# Parse configuration files, may shadow and override each other
parseConfFile(currentDir / ".blimp.conf")
if not gitRootDir.isNil:
  parseConfFile(gitRootDir / ".blimp.conf")

# If we haven't gotten a blimpstore yet, we set a default one
if blimpStore.isNil:
  blimpStore = homeDir / "blimpstore"

if existsDir(blimpStore):
  parseConfFile(blimpStore / ".blimp.conf")
parseConfFile(homeDir / ".blimp.conf")

if verbose: dumpConfig()

# These two are special, they short out
if args.showHelp: quit(help)
if args.showVersion: quit("blimp version: " & versionAsString)

# Check blimpVersion
if not blimpVersion.isNil and blimpVersion != versionAsString:
  quit("Wrong version of blimp, configuration wants: " & blimpVersion)

let command = args["command"].asString
let filenames = args["filenames"].asSeq

# Make sure the local blimpstore is setup.
setupBlimpStore()


# Do the deed
if command == "d" or command == "deflate":
  for fn in filenames:
    deflate(fn.asString)
elif command == "i" or command == "inflate":
  for fn in filenames:
    inflate(fn.asString)
elif command == "remove":
  for fn in filenames:
    remove(fn.asString)
else:
  quit("Unknown command, only (d)eflate or (i)inflate are valid.", 6)

# All good
quit(0)