How to use the gc3pie.gc3libs.backends.transport.Transport function in gc3pie

    @same_docstring_as(Transport.makedirs)
    def makedirs(self, path, mode=0777):
        dirs = path.split('/')
        if '..' in dirs:
            raise gc3libs.exceptions.InvalidArgument(
                "Path component '..' not allowed in `SshTransport.makedirs()`")
        dest = ''
        for dir in dirs:
            if dir in ['', '.']:
                continue
            dest += '/' + dir
        try:
            # check connection first
            self.connect()
            self.sftp.mkdirs(dest, mode)
        except IOError:
            # sftp.mkdir raises IOError if the directory exists;

    @same_docstring_as(Transport.chmod)
    def chmod(self, path, mode):
        try:
            os.chmod(path, mode)
        except Exception, ex:
            raise gc3libs.exceptions.TransportError(
                "Error changing local path '%s' mode to 0%o: %s: %s" 
                % (path, mode, ex.__class__.__name__, str(ex)))

    @same_docstring_as(Transport.listdir)
    def listdir(self, path):
        try:
            # check connection first
            self.connect()
            return self.sftp.listdir(path)
        except Exception as ex:
            raise gc3libs.exceptions.TransportError(
                "Could not list directory '%s' on host '%s': %s: %s"
                % (path, self.remote_frontend, ex.__class__.__name__, str(ex)))

    @same_docstring_as(Transport.get)
    def get(self, source, destination, ignore_nonexisting=False):
        try:
            gc3libs.log.debug("SshTranport.get(): remote source %s; remote host: %s; local destination: %s." 
                              % (source, self.remote_frontend, destination))
            if self.isdir(source):
                # recursively descend it
                for name in self.listdir(source):
                    # don't use `os.path.join` here, ``/`` is
                    # the right separator to use; see
                    # http://code.fabfile.org/issues/show/306
                    self.get(source + '/' + name, destination + '/' + name)
            else:
                # check connection first
                self.connect()
                self.sftp.get(source, destination)
        except Exception, ex:

    @same_docstring_as(Transport.open)
    def open(self, source, mode, bufsize=-1):
        try:
            # check connection first
            self.connect()
            return self.sftp.open(source, mode, bufsize)
        except Exception as ex:
            raise gc3libs.exceptions.TransportError(
                "Could not open file '%s' on host '%s': %s: %s"
                % (source, self.remote_frontend,
                   ex.__class__.__name__, str(ex)))

    @same_docstring_as(Transport.listdir)
    def listdir(self, path):
        try:
            # check connection first
            self.connect()
            return self.sftp.listdir(path)
        except Exception, ex:
            raise gc3libs.exceptions.TransportError("Could not list directory '%s' on host '%s': %s: %s"
                                            % (path, self.remote_frontend, 
                                               ex.__class__.__name__, str(ex)))

    @same_docstring_as(Transport.connect)
    def connect(self):
        try:
            self.transport_channel = self.ssh.get_transport()
            if not self._is_open or self.transport_channel == None or not self.transport_channel.is_active():
                gc3libs.log.info("Opening SshTransport... ")
                self.ssh.load_system_host_keys()
                self.ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
                gc3libs.log.debug(
                    "Connecting to host '%s' as user '%s' via SSH ...", 
                    self.remote_frontend, self.username)
                self.ssh.connect(self.remote_frontend,
                                 timeout=gc3libs.Default.SSH_CONNECT_TIMEOUT,
                                 username=self.username,
                                 allow_agent=True,
                                 key_filename = self.keyfile)
                self.sftp = self.ssh.open_sftp()

    @same_docstring_as(Transport.isdir)
    def isdir(self, path):
        return os.path.isdir(path)

    @same_docstring_as(Transport.remove)
    def remove(self, path):
        assert self._is_open is True, \
            "`Transport.execute_command()` called" \
            " on `Transport` instance closed / not yet open"

        try:
            gc3libs.log.debug("Removing %s", path)
            return os.remove(path)
        except Exception, ex:
            raise gc3libs.exceptions.TransportError("Could not remove file '%s': %s: %s" 
                                     % (path, ex.__class__.__name__, str(ex)))

    @same_docstring_as(Transport.remove)
    def remove(self, path):
        try:
            gc3libs.log.debug(
                "SshTransport.remove(): path: %s; remote host: %s",
                path, self.remote_frontend)
            # check connection first
            self.connect()
            self.sftp.remove(path)
        except IOError as ex:
            raise gc3libs.exceptions.TransportError(
                "Could not remove '%s' on host '%s': %s: %s"
                % (path, self.remote_frontend, ex.__class__.__name__, str(ex)))