Synnefo » snf-image-creator

# -*- coding: utf-8 -*-

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"""This module provides an interface for the rsync utility"""

import subprocess

import time

import signal

from image_creator.util import FatalError

class Rsync:

    """Wrapper class for the rsync command"""

    def __init__(self, output):

        """Create an instance """

        self._out = output

        self._exclude = []

        self._options = ['-v']

    def archive(self):

        """Enable the archive option"""

        self._options.append('-a')

        return self

    def xattrs(self):

        """Preserve extended attributes"""

        self._options.append('-X')

        return self

    def hard_links(self):

        """Preserve hard links"""

        self._options.append('-H')

        return self

    def acls(self):

        """Preserve ACLs"""

        self._options.append('-A')

        return self

    def sparse(self):

        """Handle sparse files efficiently"""

        self._options.append('-S')

        return self

    def exclude(self, pattern):

        """Add an exclude pattern"""

        self._exclude.append(pattern)

        return self

    def reset(self):

        """Reset all rsync options"""

        self._exclude = []

        self._options = ['-v']

    def run(self, src, dest, slabel='source', dlabel='destination'):

        """Run the actual command"""

        cmd = []

        cmd.append('rsync')

        cmd.extend(self._options)

        for i in self._exclude:

            cmd.extend(['--exclude', i])

        self._out.output("Calculating total number of %s files ..." % slabel,

                         False)

        # If you don't specify a destination, rsync will list the source files.

        dry_run = subprocess.Popen(cmd + [src], shell=False,

                                   stdout=subprocess.PIPE, bufsize=0)

        try:

            total = 0

            for _ in iter(dry_run.stdout.readline, b''):

                total += 1

        finally:

            dry_run.communicate()

            if dry_run.returncode != 0:

                raise FatalError("rsync failed")

        self._out.success("%d" % total)

        progress = self._out.Progress(total, "Copying files to %s" % dlabel)

        run = subprocess.Popen(cmd + [src, dest], shell=False,

                               stdout=subprocess.PIPE, bufsize=0)

        try:

            t = time.time()

            i = 0

            for _ in iter(run.stdout.readline, b''):

                i += 1

                current = time.time()

                if current - t > 0.1:

                    t = current

                    progress.goto(i)

            progress.success('done')

        finally:

            def handler(signum, frame):

                run.terminate()

                time.sleep(1)

                run.poll()

                if run.returncode is None:

                    run.kill()

                run.wait()

            signal.signal(signal.SIGALRM, handler)

            signal.alarm(2)

            run.communicate()

            signal.alarm(0)

            if run.returncode != 0:

                raise FatalError("rsync failed")

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