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# Copyright (c) 2013, Red Hat, Inc. All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#
# 1. Redistributions of source code must retain the above copyright notice,
# this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright notice,
# this list of conditions and the following disclaimer in the documentation
# and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
# POSSIBILITY OF SUCH DAMAGE.
#
# The views and conclusions contained in the software and documentation are
# those of the authors and should not be interpreted as representing official
# policies, either expressed or implied, of the FreeBSD Project.
#
# Authors: Michal Minar <miminar@redhat.com>
#
"""
Module for session object representing all connection to remote hosts.
"""
from collections import defaultdict
from lmi.scripts.common import errors
from lmi.scripts.common import get_logger
from lmi.shell.LMIConnection import connect
LOG = get_logger(__name__)
class Session(object):
"""
Session object keeps connection objects to remote hosts. Their are
associated with particular hostnames. It also caches credentials for them.
Connections are made as they are needed. When credentials are missing
for connection to be made, the user is asked to supply them from
standard input.
:param app: Instance of main application.
:param list hosts: List of hostname strings.
:param dictionary credentials: Mapping assigning a pair
``(user, password)`` to each hostname.
:param boolean same_credentials: Use the same credentials for all
hosts in session. The first credentials given will be used.
"""
def __init__(self, app, hosts, credentials=None, same_credentials=False):
self._app = app
self._connections = {h: None for h in hosts}
# { hostname : (username, password, verified), ... }
# where verified is a flag saying, whether these credentials
# were successfuly used for logging in
self._credentials = defaultdict(lambda: ('', '', False))
self._same_credentials = same_credentials
if credentials is not None:
if not isinstance(credentials, dict):
raise TypeError("credentials must be a dictionary")
for hostname, creds in credentials.items():
credentials[hostname] = (creds[0], creds[1], False)
self._credentials.update(credentials)
def __getitem__(self, hostname):
"""
:rtype: (``LMIConnection``) Connection object to remote host.
``None`` if connection can not be made.
"""
if self._connections[hostname] is None:
self._connections[hostname] = self._connect(
hostname, interactive=True)
return self._connections[hostname]
def __len__(self):
""" Get the number of hostnames in session. """
return len(self._connections)
def __iter__(self):
""" Yields connection objects. """
successful_connections = 0
for hostname in self._connections:
try:
connection = self[hostname]
if connection is not None:
yield connection
successful_connections += 1
except Exception as exc:
LOG().error('failed to make a connection to "%s": %s',
hostname, exc)
if successful_connections == 0:
raise errors.LmiNoConnections('no successful connection made')
def _connect(self, hostname, interactive=False):
"""
Makes the connection to host.
:param string hostname: Name of host.
:param boolean interactive: Whether we can interact with user
and expect a reply from him.
:returns: Connection to remote host or ``None``.
:rtype: :py:class:`lmi.shell.LMIConnection` or ``None``
"""
username, password = self.get_credentials(hostname)
kwargs = {
'verify_server_cert' : self._app.config.verify_server_cert,
'interactive' : interactive
}
if len(self._connections) > 1:
kwargs['prompt_prefix'] = '[%s] ' % hostname
connection = connect(hostname, username, password, **kwargs)
if connection is not None:
LOG().debug('connection to host "%s" successfully created',
hostname)
tp = connection._client._cliconn.creds
if tp is None:
tp = ('', '')
self._credentials[hostname] = (tp[0], tp[1], True)
else:
LOG().error('failed to connect to host "%s"', hostname)
return connection
@property
def hostnames(self):
"""
List of hostnames in session.
:rtype: list
"""
return self._connections.keys()
def get_credentials(self, hostname):
"""
:param string hostname: Name of host to get credentials for.
:returns: Pair of ``(username, password)`` for given hostname. If no
credentials were given for this host, ``('', '')`` is returned.
:rtype: tuple
"""
username, password, verified = self._credentials[hostname]
if ( not verified
and (not username or not password)
and self._same_credentials):
for tp in self._credentials.values():
if tp[2]:
username, password = tp[0], tp[1]
break
return username, password
def get_unconnected(self):
"""
:returns: List of hostnames, which do not have associated connection
yet.
:rtype: list
"""
return [h for h, c in self._connections.items() if c is None]
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