Sync files using rsync.

    By default, a local ``source`` is pushed to a remote
    ``destination``. To pull from a remote ``source`` to a local
    ``destination`` instead, pass ``pull=True``.

def sync(source,
         destination,
         host,
         user=None,
         sudo=False,
         run_as=None,
         options=('-rltvz', '--no-perms', '--no-group'),
         excludes=(),
         exclude_from=None,
         delete=False,
         dry_run=False,
         mode='u=rwX,g=rwX,o=',
         quiet=True,
         pull=False,
         # Args passed through to local command:
         stdout: arg(type=StreamOptions) = None,
         stderr: arg(type=StreamOptions) = None,
         echo=False,
         raise_on_error=True,
         ) -> Result:
    """Sync files using rsync.

    By default, a local ``source`` is pushed to a remote
    ``destination``. To pull from a remote ``source`` to a local
    ``destination`` instead, pass ``pull=True``.

    """
    source = abs_path(source, keep_slash=True)
    destination = abs_path(destination, keep_slash=True)
    connection_str = '{user}@{host}'.format_map(locals()) if user else host
    push = not pull

    if sudo:
        rsync_path = ('--rsync-path', 'sudo rsync')
    elif run_as:
        rsync_path = ('--rsync-path', 'sudo -u {run_as} rsync'.format_map(locals()))
    else:
        rsync_path = None

    if push:
        destination = '{connection_str}:{destination}'.format_map(locals())
    else:
        source = '{connection_str}:{source}'.format_map(locals())

    args = (
        'rsync',
        rsync_path,
        options,
        ('--chmod', mode) if mode else None,
        tuple(('--exclude', exclude) for exclude in excludes),
        ('--exclude-from', exclude_from) if exclude_from else None,
        '--delete' if delete else None,
        '--dry-run' if dry_run else None,
        '--quiet' if quiet else None,
        source,
        destination,
    )
    return local(args, stdout=stdout, stderr=stderr, echo=echo, raise_on_error=raise_on_error)