The Gatekeeper, or a project gating system
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
import logging
from zuul import model
from zuul.zk import LockException
class Nodepool(object):
log = logging.getLogger('zuul.nodepool')
def __init__(self, scheduler):
self.requests = {}
self.sched = scheduler
def emitStats(self, request):
# Implements the following :
# counter zuul.nodepool.requests.<state>.total
# counter zuul.nodepool.requests.<state>.label.<label>
# counter zuul.nodepool.requests.<state>.size.<size>
# timer zuul.nodepool.requests.(fulfilled|failed)
# timer zuul.nodepool.requests.(fulfilled|failed).<label>
# timer zuul.nodepool.requests.(fulfilled|failed).<size>
# gauge zuul.nodepool.current_requests
if not self.sched.statsd:
return
statsd = self.sched.statsd
pipe = statsd.pipeline()
state = request.state
dt = None
if request.canceled:
state = 'canceled'
elif request.state in (model.STATE_FULFILLED, model.STATE_FAILED):
dt = int((request.state_time - request.requested_time) * 1000)
key = 'zuul.nodepool.requests.%s' % state
pipe.incr(key + ".total")
if dt:
pipe.timing(key, dt)
for node in request.nodeset.getNodes():
pipe.incr(key + '.label.%s' % node.label)
if dt:
pipe.timing(key + '.label.%s' % node.label, dt)
pipe.incr(key + '.size.%s' % len(request.nodeset.nodes))
if dt:
pipe.timing(key + '.size.%s' % len(request.nodeset.nodes), dt)
pipe.gauge('zuul.nodepool.current_requests', len(self.requests))
pipe.send()
def requestNodes(self, build_set, job, relative_priority):
# Create a copy of the nodeset to represent the actual nodes
# returned by nodepool.
nodeset = job.nodeset.copy()
req = model.NodeRequest(self.sched.hostname, build_set, job,
nodeset, relative_priority)
self.requests[req.uid] = req
if nodeset.nodes:
self.sched.zk.submitNodeRequest(req, self._updateNodeRequest)
# Logged after submission so that we have the request id
self.log.info("Submitted node request %s" % (req,))
self.emitStats(req)
else:
self.log.info("Fulfilling empty node request %s" % (req,))
req.state = model.STATE_FULFILLED
self.sched.onNodesProvisioned(req)
del self.requests[req.uid]
return req
def cancelRequest(self, request):
self.log.info("Canceling node request %s" % (request,))
if request.uid in self.requests:
request.canceled = True
try:
self.sched.zk.deleteNodeRequest(request)
except Exception:
self.log.exception("Error deleting node request:")
def reviseRequest(self, request, relative_priority=None):
'''Attempt to update the node request, if it is not currently being
processed.
:param: NodeRequest request: The request to update.
:param relative_priority int: If supplied, the new relative
priority to set on the request.
'''
if relative_priority is None:
return
try:
self.sched.zk.lockNodeRequest(request, blocking=False)
except LockException:
# It may be locked by nodepool, which is fine.
self.log.debug("Unable to revise locked node request %s", request)
return False
try:
old_priority = request.relative_priority
request.relative_priority = relative_priority
self.sched.zk.storeNodeRequest(request)
self.log.debug("Revised relative priority of "
"node request %s from %s to %s",
request, old_priority, relative_priority)
except Exception:
self.log.exception("Unable to update node request %s", request)
finally:
try:
self.sched.zk.unlockNodeRequest(request)
except Exception:
self.log.exception("Unable to unlock node request %s", request)
def holdNodeSet(self, nodeset, autohold_key):
'''
Perform a hold on the given set of nodes.
:param NodeSet nodeset: The object containing the set of nodes to hold.
:param set autohold_key: A set with the tenant/project/job names
associated with the given NodeSet.
'''
self.log.info("Holding nodeset %s" % (nodeset,))
(hold_iterations,
reason,
node_hold_expiration) = self.sched.autohold_requests[autohold_key]
nodes = nodeset.getNodes()
for node in nodes:
if node.lock is None:
raise Exception("Node %s is not locked" % (node,))
node.state = model.STATE_HOLD
node.hold_job = " ".join(autohold_key)
node.comment = reason
if node_hold_expiration:
node.hold_expiration = node_hold_expiration
self.sched.zk.storeNode(node)
# We remove the autohold when the number of nodes in hold
# is equal to or greater than (run iteration count can be
# altered) the number of nodes used in a single job run
# times the number of run iterations requested.
nodes_in_hold = self.sched.zk.heldNodeCount(autohold_key)
if nodes_in_hold >= len(nodes) * hold_iterations:
self.log.debug("Removing autohold for %s", autohold_key)
del self.sched.autohold_requests[autohold_key]
def useNodeSet(self, nodeset):
self.log.info("Setting nodeset %s in use" % (nodeset,))
for node in nodeset.getNodes():
if node.lock is None:
raise Exception("Node %s is not locked" % (node,))
node.state = model.STATE_IN_USE
self.sched.zk.storeNode(node)
def returnNodeSet(self, nodeset, build=None):
self.log.info("Returning nodeset %s" % (nodeset,))
if (build and build.start_time and build.end_time and
build.build_set and build.build_set.item and
build.build_set.item.change and
build.build_set.item.change.project):
duration = build.end_time - build.start_time
project = build.build_set.item.change.project
self.log.info("Nodeset %s with %s nodes was in use "
"for %s seconds for build %s for project %s",
nodeset, len(nodeset.nodes), duration, build,
project)
for node in nodeset.getNodes():
if node.lock is None:
self.log.error("Node %s is not locked" % (node,))
else:
try:
if node.state == model.STATE_IN_USE:
node.state = model.STATE_USED
self.sched.zk.storeNode(node)
except Exception:
self.log.exception("Exception storing node %s "
"while unlocking:" % (node,))
self._unlockNodes(nodeset.getNodes())
def unlockNodeSet(self, nodeset):
self._unlockNodes(nodeset.getNodes())
def _unlockNodes(self, nodes):
for node in nodes:
try:
self.sched.zk.unlockNode(node)
except Exception:
self.log.exception("Error unlocking node:")
def lockNodeSet(self, nodeset, request_id):
self._lockNodes(nodeset.getNodes(), request_id)
def _lockNodes(self, nodes, request_id):
# Try to lock all of the supplied nodes. If any lock fails,
# try to unlock any which have already been locked before
# re-raising the error.
locked_nodes = []
try:
for node in nodes:
if node.allocated_to != request_id:
raise Exception("Node %s allocated to %s, not %s" %
(node.id, node.allocated_to, request_id))
self.log.debug("Locking node %s" % (node,))
self.sched.zk.lockNode(node, timeout=30)
locked_nodes.append(node)
except Exception:
self.log.exception("Error locking nodes:")
self._unlockNodes(locked_nodes)
raise
def _updateNodeRequest(self, request, deleted):
# Return False to indicate that we should stop watching the
# node.
self.log.debug("Updating node request %s" % (request,))
if request.uid not in self.requests:
self.log.debug("Request %s is unknown" % (request.uid,))
return False
if request.canceled:
del self.requests[request.uid]
self.emitStats(request)
return False
# TODOv3(jeblair): handle allocation failure
if deleted:
self.log.debug("Resubmitting lost node request %s" % (request,))
request.id = None
self.sched.zk.submitNodeRequest(request, self._updateNodeRequest)
elif request.state in (model.STATE_FULFILLED, model.STATE_FAILED):
self.log.info("Node request %s %s" % (request, request.state))
# Give our results to the scheduler.
self.sched.onNodesProvisioned(request)
del self.requests[request.uid]
self.emitStats(request)
# Stop watching this request node.
return False
return True
def acceptNodes(self, request, request_id):
# Called by the scheduler when it wants to accept and lock
# nodes for (potential) use. Return False if there is a
# problem with the request (canceled or retrying), True if it
# is ready to be acted upon (success or failure).
self.log.info("Accepting node request %s" % (request,))
if request_id != request.id:
self.log.info("Skipping node accept for %s (resubmitted as %s)",
request_id, request.id)
return False
if request.canceled:
self.log.info("Ignoring canceled node request %s" % (request,))
# The request was already deleted when it was canceled
return False
# If we didn't request nodes and the request is fulfilled then just
# return. We don't have to do anything in this case. Further don't even
# ask ZK for the request as empty requests are not put into ZK.
if not request.nodeset.nodes and request.fulfilled:
return True
# Make sure the request still exists. It's possible it could have
# disappeared if we lost the ZK session between when the fulfillment
# response was added to our queue, and when we actually get around to
# processing it. Nodepool will automatically reallocate the assigned
# nodes in that situation.
try:
if not self.sched.zk.nodeRequestExists(request):
self.log.info("Request %s no longer exists, resubmitting",
request.id)
request.id = None
request.state = model.STATE_REQUESTED
self.requests[request.uid] = request
self.sched.zk.submitNodeRequest(
request, self._updateNodeRequest)
return False
except Exception:
# If we cannot retrieve the node request from ZK we probably lost
# the connection and thus the ZK session. Resubmitting the node
# request probably doesn't make sense at this point in time as it
# is likely to directly fail again. So just log the problem
# with zookeeper and fail here.
self.log.exception("Error getting node request %s:" % request_id)
request.failed = True
return True
locked = False
if request.fulfilled:
# If the request suceeded, try to lock the nodes.
try:
self.lockNodeSet(request.nodeset, request.id)
locked = True
except Exception:
self.log.exception("Error locking nodes:")
request.failed = True
# Regardless of whether locking (or even the request)
# succeeded, delete the request.
self.log.debug("Deleting node request %s" % (request,))
try:
self.sched.zk.deleteNodeRequest(request)
except Exception:
self.log.exception("Error deleting node request:")
request.failed = True
# If deleting the request failed, and we did lock the
# nodes, unlock the nodes since we're not going to use
# them.
if locked:
self.unlockNodeSet(request.nodeset)
return True