/usr/lib/python3/dist-packages/ClusterShell/Propagation.py is in python3-clustershell 1.8-1.
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# Copyright (C) 2010-2016 CEA/DAM
# Copyright (C) 2010-2011 Henri Doreau <henri.doreau@cea.fr>
# Copyright (C) 2015-2017 Stephane Thiell <sthiell@stanford.edu>
#
# This file is part of ClusterShell.
#
# ClusterShell 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.
#
# ClusterShell 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 ClusterShell; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
"""
ClusterShell Propagation module. Use the topology tree to send commands
through gateways and gather results.
"""
from collections import deque
import logging
from ClusterShell.Defaults import DEFAULTS
from ClusterShell.NodeSet import NodeSet
from ClusterShell.Communication import Channel
from ClusterShell.Communication import ControlMessage, StdOutMessage
from ClusterShell.Communication import StdErrMessage, RetcodeMessage
from ClusterShell.Communication import StartMessage, EndMessage
from ClusterShell.Communication import RoutedMessageBase, ErrorMessage
from ClusterShell.Communication import ConfigurationMessage, TimeoutMessage
from ClusterShell.Topology import TopologyError
class RouteResolvingError(Exception):
"""error raised on invalid conditions during routing operations"""
class PropagationTreeRouter(object):
"""performs routes resolving operations within a propagation tree.
This object provides a next_hop method, that will look for the best
directly connected node to use to forward a message to a remote
node.
Upon instanciation, the router will parse the topology tree to
generate its routing table.
"""
def __init__(self, root, topology, fanout=0):
self.root = root
self.topology = topology
self.fanout = fanout
self.nodes_fanin = {}
self.table = None
self.table_generate(root, topology)
self._unreachable_hosts = NodeSet()
def table_generate(self, root, topology):
"""The router relies on a routing table. The keys are the
destination nodes and the values are the next hop gateways to
use to reach these nodes.
"""
try:
root_group = topology.find_nodegroup(root)
except TopologyError:
msgfmt = "Invalid root or gateway node: %s"
raise RouteResolvingError(msgfmt % root)
self.table = []
for group in root_group.children():
dest = NodeSet()
stack = [group]
while len(stack) > 0:
curr = stack.pop()
dest.update(curr.children_ns())
stack += curr.children()
self.table.append((dest, group.nodeset))
def dispatch(self, dst):
"""dispatch nodes from a target nodeset to the directly
connected gateways.
The method acts as an iterator, returning a gateway and the
associated hosts. It should provide a rather good load balancing
between the gateways.
"""
### Disabled to handle all remaining nodes as directly connected nodes
## Check for directly connected targets
#res = [tmp & dst for tmp in self.table.values()]
#nexthop = NodeSet()
#[nexthop.add(x) for x in res]
#if len(nexthop) > 0:
# yield nexthop, nexthop
# Check for remote targets, that require a gateway to be reached
for network, _ in self.table:
dst_inter = network & dst
dst.difference_update(dst_inter)
for host in dst_inter.nsiter():
yield self.next_hop(host), host
# remaining nodes are considered as directly connected nodes
if dst:
yield dst, dst
def next_hop(self, dst):
"""perform the next hop resolution. If several hops are
available, then, the one with the least number of current jobs
will be returned
"""
if dst in self._unreachable_hosts:
raise RouteResolvingError(
'Invalid destination: %s, host is unreachable' % dst)
# can't resolve if source == destination
if self.root == dst:
raise RouteResolvingError(
'Invalid resolution request: %s -> %s' % (self.root, dst))
## ------------------
# the routing table is organized this way:
#
# NETWORK | NEXT HOP
# ------------+-----------
# node[0-9] | gateway0
# node[10-19] | gateway[1-2]
# ...
# ---------
for network, nexthops in self.table:
# destination contained in current network
if dst in network:
res = self._best_next_hop(nexthops)
if res is None:
raise RouteResolvingError('No route available to %s' % \
str(dst))
self.nodes_fanin[res] += len(dst)
return res
# destination contained in current next hops (ie. directly
# connected)
if dst in nexthops:
return dst
raise RouteResolvingError(
'No route from %s to host %s' % (self.root, dst))
def mark_unreachable(self, dst):
"""mark node dst as unreachable and don't advertise routes
through it anymore. The cache will be updated only when
necessary to avoid performing expensive traversals.
"""
# Simply mark dst as unreachable in a dedicated NodeSet. This
# list will be consulted by the resolution method
self._unreachable_hosts.add(dst)
def _best_next_hop(self, candidates):
"""find out a good next hop gateway"""
backup = None
backup_connections = 1e400 # infinity
candidates = candidates.difference(self._unreachable_hosts)
for host in candidates:
# the router tracks established connections in the
# nodes_fanin table to avoid overloading a gateway
connections = self.nodes_fanin.setdefault(host, 0)
# FIXME
#if connections < self.fanout:
# # currently, the first one is the best
# return host
if backup_connections > connections:
backup = host
backup_connections = connections
return backup
class PropagationChannel(Channel):
"""Admin node propagation logic. Instances are able to handle
incoming messages from a directly connected gateway, process them
and reply.
In order to take decisions, the instance acts as a finite states
machine, whose current state evolves according to received data.
-- INTERNALS --
Instance can be in one of the 4 different states:
- init (implicit)
This is the very first state. The instance enters the init
state at start() method, and will then send the configuration
to the remote node. Once the configuration is sent away, the
state changes to cfg.
- cfg
During this second state, the instance will wait for a valid
acknowledgement from the gateway to the previously sent
configuration message. If such a message is delivered, the
control message (the one that contains the actions to perform)
is sent, and the state is set to ctl.
- ctl
Third state, the instance is waiting for a valid ack for from
the gateway to the ctl packet. Then, the state switch to gtr
(gather).
- gtr
Final state: wait for results from the subtree and store them.
"""
def __init__(self, task, gateway):
"""
"""
Channel.__init__(self)
self.task = task
self.gateway = gateway
self.workers = {}
self._cfg_write_hist = deque() # track write requests
self._sendq = deque()
self._rc = None
self.logger = logging.getLogger(__name__)
def send_queued(self, ctl):
"""helper used to send a message, using msg queue if needed"""
if self.setup and not self._sendq:
# send now if channel is setup and sendq empty
self.send(ctl)
else:
self.logger.debug("send_queued: %d", len(self._sendq))
self._sendq.appendleft(ctl)
def send_dequeue(self):
"""helper used to send one queued message (if any)"""
if self._sendq:
ctl = self._sendq.pop()
self.logger.debug("dequeuing sendq: %s", ctl)
self.send(ctl)
def start(self):
"""start propagation channel"""
self._init()
self._open()
# Immediately send CFG
cfg = ConfigurationMessage(self.gateway)
cfg.data_encode(self.task.topology)
self.send(cfg)
def recv(self, msg):
"""process incoming messages"""
self.logger.debug("recv: %s", msg)
if msg.type == EndMessage.ident:
#??#self.ptree.notify_close()
self.logger.debug("got EndMessage; closing")
# abort worker (now working)
self.worker.abort()
elif self.setup:
self.recv_ctl(msg)
elif self.opened:
self.recv_cfg(msg)
elif msg.type == StartMessage.ident:
self.opened = True
self.logger.debug('channel started (version %s on remote gateway)',
self._xml_reader.version)
else:
self.logger.error('unexpected message: %s', str(msg))
def shell(self, nodes, command, worker, timeout, stderr, gw_invoke_cmd,
remote):
"""command execution through channel"""
self.logger.debug("shell nodes=%s timeout=%s worker=%s remote=%s",
nodes, timeout, id(worker), remote)
self.workers[id(worker)] = worker
ctl = ControlMessage(id(worker))
ctl.action = 'shell'
ctl.target = nodes
# keep only valid task info pairs
info = dict((k, v) for k, v in self.task._info.items()
if k not in DEFAULTS._task_info_pkeys_bl)
ctl_data = {
'cmd': command,
'invoke_gateway': gw_invoke_cmd, # XXX
'taskinfo': info,
'stderr': stderr,
'timeout': timeout,
'remote': remote,
}
ctl.data_encode(ctl_data)
self.send_queued(ctl)
def write(self, nodes, buf, worker):
"""write buffer through channel to nodes on standard input"""
self.logger.debug("write buflen=%d", len(buf))
assert id(worker) in self.workers
ctl = ControlMessage(id(worker))
ctl.action = 'write'
ctl.target = nodes
ctl_data = {
'buf': buf,
}
ctl.data_encode(ctl_data)
self._cfg_write_hist.appendleft((ctl.msgid, nodes, len(buf), worker))
self.send_queued(ctl)
def set_write_eof(self, nodes, worker):
"""send EOF through channel to specified nodes"""
self.logger.debug("set_write_eof")
assert id(worker) in self.workers
ctl = ControlMessage(id(worker))
ctl.action = 'eof'
ctl.target = nodes
self.send_queued(ctl)
def recv_cfg(self, msg):
"""handle incoming messages for state 'propagate configuration'"""
self.logger.debug("recv_cfg")
if msg.type == 'ACK':
self.logger.debug("CTL - connection with gateway fully established")
self.setup = True
self.send_dequeue()
else:
self.logger.debug("_state_config error (msg=%s)", msg)
def recv_ctl(self, msg):
"""handle incoming messages for state 'control'"""
if msg.type == 'ACK':
self.logger.debug("got ack (%s)", msg.type)
# check if ack matches write history msgid to generate ev_written
if self._cfg_write_hist and msg.ack == self._cfg_write_hist[-1][0]:
_, nodes, bytes_count, metaworker = self._cfg_write_hist.pop()
for node in nodes:
# we are losing track of the gateway here, we could override
# on_written in TreeWorker if needed (eg. for stats)
metaworker._on_written(node, bytes_count, 'stdin')
self.send_dequeue()
elif isinstance(msg, RoutedMessageBase):
metaworker = self.workers[msg.srcid]
if msg.type == StdOutMessage.ident:
nodeset = NodeSet(msg.nodes)
# msg.data_decode()'s name is a bit confusing, but returns
# pickle-decoded bytes (encoded string) and not string...
decoded = msg.data_decode() + b'\n'
for line in decoded.splitlines():
for node in nodeset:
metaworker._on_remote_node_msgline(node, line, 'stdout',
self.gateway)
elif msg.type == StdErrMessage.ident:
nodeset = NodeSet(msg.nodes)
decoded = msg.data_decode() + b'\n'
for line in decoded.splitlines():
for node in nodeset:
metaworker._on_remote_node_msgline(node, line, 'stderr',
self.gateway)
elif msg.type == RetcodeMessage.ident:
rc = msg.retcode
for node in NodeSet(msg.nodes):
metaworker._on_remote_node_close(node, rc, self.gateway)
elif msg.type == TimeoutMessage.ident:
self.logger.debug("TimeoutMessage for %s", msg.nodes)
for node in NodeSet(msg.nodes):
metaworker._on_remote_node_timeout(node, self.gateway)
elif msg.type == ErrorMessage.ident:
# tree runtime error, could generate a new event later
raise TopologyError("%s: %s" % (self.gateway, msg.reason))
else:
self.logger.debug("recv_ctl: unhandled msg %s", msg)
"""
return
if self.ptree.upchannel is not None:
self.logger.debug("_state_gather ->upchan %s" % msg)
self.ptree.upchannel.send(msg) # send to according event handler passed by shell()
else:
assert False
"""
def ev_hup(self, worker, node, rc):
"""Channel command is closing"""
self._rc = rc
def ev_close(self, worker, timedout):
"""Channel is closing"""
# do not use worker buffer or rc accessors here as we doesn't use
# common stream names
gateway = str(worker.nodes)
self.logger.debug("ev_close gateway=%s %s", gateway, self)
self.logger.debug("ev_close rc=%s", self._rc) # may be None
if self._rc: # got explicit error code
# ev_routing?
self.logger.debug("unreachable gateway %s", gateway)
worker.task.router.mark_unreachable(gateway)
self.logger.debug("worker.task.gateways=%s", worker.task.gateways)
# TODO: find best gateway, update TreeWorker counters, relaunch...
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