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# copyright 2003-2011 LOGILAB S.A. (Paris, FRANCE), all rights reserved.
# contact http://www.logilab.fr/ -- mailto:contact@logilab.fr
#
# This file is part of logilab-common.
#
# logilab-common is free software: you can redistribute it and/or modify it under
# the terms of the GNU Lesser General Public License as published by the Free
# Software Foundation, either version 2.1 of the License, or (at your option) any
# later version.
#
# logilab-common is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
# details.
#
# You should have received a copy of the GNU Lesser General Public License along
# with logilab-common. If not, see <http://www.gnu.org/licenses/>.
"""Python Remote Object utilities
Main functions available:
* `register_object` to expose arbitrary object through pyro using delegation
approach and register it in the nameserver.
* `ns_unregister` unregister an object identifier from the nameserver.
* `ns_get_proxy` get a pyro proxy from a nameserver object identifier.
"""
__docformat__ = "restructuredtext en"
import logging
import tempfile
from Pyro import core, naming, errors, util, config
_LOGGER = logging.getLogger('pyro')
_MARKER = object()
config.PYRO_STORAGE = tempfile.gettempdir()
def ns_group_and_id(idstr, defaultnsgroup=_MARKER):
try:
nsgroup, nsid = idstr.rsplit('.', 1)
except ValueError:
if defaultnsgroup is _MARKER:
nsgroup = config.PYRO_NS_DEFAULTGROUP
else:
nsgroup = defaultnsgroup
nsid = idstr
if nsgroup is not None and not nsgroup.startswith(':'):
nsgroup = ':' + nsgroup
return nsgroup, nsid
def host_and_port(hoststr):
if not hoststr:
return None, None
try:
hoststr, port = hoststr.split(':')
except ValueError:
port = None
else:
port = int(port)
return hoststr, port
_DAEMONS = {}
_PYRO_OBJS = {}
def _get_daemon(daemonhost, start=True):
if not daemonhost in _DAEMONS:
if not start:
raise Exception('no daemon for %s' % daemonhost)
if not _DAEMONS:
core.initServer(banner=0)
host, port = host_and_port(daemonhost)
daemon = core.Daemon(host=host, port=port)
_DAEMONS[daemonhost] = daemon
return _DAEMONS[daemonhost]
def locate_ns(nshost):
"""locate and return the pyro name server to the daemon"""
core.initClient(banner=False)
return naming.NameServerLocator().getNS(*host_and_port(nshost))
def register_object(object, nsid, defaultnsgroup=_MARKER,
daemonhost=None, nshost=None, use_pyrons=True):
"""expose the object as a pyro object and register it in the name-server
if use_pyrons is False, then the object is exposed, but no
attempt to register it to a pyro nameserver is made.
return the pyro daemon object
"""
nsgroup, nsid = ns_group_and_id(nsid, defaultnsgroup)
daemon = _get_daemon(daemonhost)
if use_pyrons:
nsd = locate_ns(nshost)
# make sure our namespace group exists
try:
nsd.createGroup(nsgroup)
except errors.NamingError:
pass
daemon.useNameServer(nsd)
# use Delegation approach
impl = core.ObjBase()
impl.delegateTo(object)
qnsid = '%s.%s' % (nsgroup, nsid)
uri = daemon.connect(impl, qnsid)
_PYRO_OBJS[qnsid] = str(uri)
_LOGGER.info('registered %s a pyro object using group %s and id %s',
object, nsgroup, nsid)
return daemon
def get_object_uri(qnsid):
return _PYRO_OBJS[qnsid]
def ns_unregister(nsid, defaultnsgroup=_MARKER, nshost=None):
"""unregister the object with the given nsid from the pyro name server"""
nsgroup, nsid = ns_group_and_id(nsid, defaultnsgroup)
try:
nsd = locate_ns(nshost)
except errors.PyroError, ex:
# name server not responding
_LOGGER.error('can\'t locate pyro name server: %s', ex)
else:
try:
nsd.unregister('%s.%s' % (nsgroup, nsid))
_LOGGER.info('%s unregistered from pyro name server', nsid)
except errors.NamingError:
_LOGGER.warning('%s not registered in pyro name server', nsid)
def ns_reregister(nsid, defaultnsgroup=_MARKER, nshost=None):
"""reregister a pyro object into the name server. You only have to specify
the name-server id of the object (though you MUST have gone through
`register_object` for the given object previously).
This is especially useful for long running server while the name server may
have been restarted, and its records lost.
"""
nsgroup, nsid = ns_group_and_id(nsid, defaultnsgroup)
qnsid = '%s.%s' % (nsgroup, nsid)
nsd = locate_ns(nshost)
try:
nsd.unregister(qnsid)
except errors.NamingError:
# make sure our namespace group exists
try:
nsd.createGroup(nsgroup)
except errors.NamingError:
pass
nsd.register(qnsid, _PYRO_OBJS[qnsid])
def ns_get_proxy(nsid, defaultnsgroup=_MARKER, nshost=None):
"""
if nshost is None, the nameserver is found by a broadcast.
"""
# resolve the Pyro object
nsgroup, nsid = ns_group_and_id(nsid, defaultnsgroup)
try:
nsd = locate_ns(nshost)
pyrouri = nsd.resolve('%s.%s' % (nsgroup, nsid))
except errors.ProtocolError, ex:
raise errors.PyroError(
'Could not connect to the Pyro name server (host: %s)' % nshost)
except errors.NamingError:
raise errors.PyroError(
'Could not get proxy for %s (not registered in Pyro), '
'you may have to restart your server-side application' % nsid)
return core.getProxyForURI(pyrouri)
def get_proxy(pyro_uri):
"""get a proxy for the passed pyro uri without using a nameserver
"""
return core.getProxyForURI(pyro_uri)
def set_pyro_log_threshold(level):
pyrologger = logging.getLogger('Pyro.%s' % str(id(util.Log)))
# remove handlers so only the root handler is used
pyrologger.handlers = []
pyrologger.setLevel(level)
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