Add pylint to depot_tools.

third_party/logilab/common/pyro_ext.py

+# 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)