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, is a single binary without
  # need for Python, and has less features than git-fat. So far.

  #

  # 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 an md5sum string inside it.
  #
  # The file is copied over into:

  #  <homedir>/blimpStore/<originalfilename>-<md5sum>
  #
  # Configuration is in:
  #   <gitroot>/.blimp.conf
  #   ~/blimpstore/.blimp.conf

  var

    blimpStore, uploadCommandFormat, downloadCommandFormat, deleteCommandFormat, rsyncPassword: string

    remoteBlimpStore: string = nil
    verbose: bool

  let
    defaultConfig = """
  [rsync]

  # Set this to your remote rsync daemon area

  remote = "blimpuser@some-rsync-server.com::blimpstore"
  password = some-good-rsync-password-for-blimpuser

  
  # The following three formats should not need editing

  # $1 is filename, $2 is remote and $3 is the local blimpstore

  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

  delete = "rsync --password-file $3/.blimp.pass -dv --delete --existing --ignore-existing --include '$1' --exclude '*' $3/ $2"

  """

  # Load blimp.conf file, overkill for now but...

  proc parseConfFile(filename: string) =

    var f = newFileStream(filename, fmRead)
    if f != nil:
      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 "remote":

            remoteBlimpStore = e.value

          of "upload":
            uploadCommandFormat = e.value
          of "download":
            downloadCommandFormat = e.value

          of "delete":
            deleteCommandFormat = e.value

          of "password":
            rsyncPassword = 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 =
    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):
      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)
    copyFile(blimpStore / blimpFilename, filename)

  # Delete from blimpStore and remote.
  proc deleteFromBlimpStore(blimpFilename, filename: string) =
    if existsFile(blimpStore / blimpFilename):
      removeFile(blimpStore / blimpFilename)
    remoteDeleteFile(blimpFilename)
  
  # Pick out blimpFilename (filename & "-" & hash)
  proc blimpFileName(filename: string): string=
    var hashfile: File
    if not open(hashfile, filename):
      quit("Failed opening file: " & filename, 4)
    let hashline = split(string(readLine(hashfile)), {':'})
    if hashline[0] == "hash":
      result = hashline[1]
    else:
      result = nil
  
  # Get hash and compute blimpFilename
  proc computeBlimpFilename(filename: string): string =
    result = blimpFilename(filename)
    if result.isNil:
      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) =

    let blimpFilename = computeBlimpFilename(filename)

    copyToBlimpStore(filename, blimpFilename)
    writeFile(filename, "hash:" & blimpFilename)

    echo("\t" & filename & " deflated.")

  
  proc isInBlimpStore(filename: string): bool =
    let blimpFilename = blimpFilename(filename)
    if not blimpFilename.isNil:
      return true

  # Parse out hash from hash stub and copy back original content from blimpStore.

  proc inflate(filename: string) =

    let blimpFilename = blimpFilename(filename)
    if blimpFilename.isNil:
      echo("\t" & filename & " is not deflated, skipping.", 5)
    else:
      copyFromBlimpStore(blimpfilename, filename)
      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.")

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

  let help = """
    blimp [options] <command> <filenames...>
      -v,--verbose             Verbosity

      <command>   (string)     (d)eflate, (i)nflate, delete, (c)heck, (r)ecover

      <filenames> (string...)  One or more filepaths to inflate/deflate

      
      Edit ~/blimpstore/.blimp.conf or <gitroot>/.blimp.conf and set a proper
      remote and also create ~/blimp.pass with the proper rsync password to use.
      
      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 ~/blimpstore, and if configured also upload it to
      remote, using rsync.
      
      Inflate will bring back the original content by copying from
      ~/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.
      
      Remove (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 #####################################
  

  # Hardwired to "blimpstore" directory in home dir.
  blimpStore = getHomeDir() / "blimpstore"

  
  # Make sure we have the dir, or create it.
  try:

    if not existsDir(blimpStore):
      createDir(blimpStore)
    if not existsFile(blimpStore / ".blimp.conf"):
      writeFile(blimpStore / ".blimp.conf", defaultConfig)

  except:

    quit("Could not create " & blimpStore & " directory.", 1)

  # Parse configuration files if they exist

  # The one in gitroot overrides settings from the store.

  parseConfFile(blimpStore / ".blimp.conf")

  parseConfFile(gitRoot() / ".blimp.conf")
  

  # Using lapp to get args
  let args = parse(help)
  let command = args["command"].asString
  let filenames = args["filenames"].asSeq
  verbose = args["verbose"].asBool

  
  # 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)