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Very rough cut of restarting a failed node

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This commit is contained in:
Floris Bruynooghe
2014-09-15 01:20:45 +02:00
parent 969582187e
commit f643991f7f
2 changed files with 307 additions and 106 deletions
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308
xdist/dsession.py
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@@ -59,54 +59,162 @@ class EachScheduling:
class LoadScheduling:
"""Implement load scheduling accross nodes.
This distributes the tests collected across all nodes so each test
is run just once. All nodes collect and submit the test suit and
when all collections are received it is verified they are
identical collections. Then the collection gets devided up in
chunks and chunks get submitted to nodes. The first node
finishing it's chunk gets the next chunk until all tests are done.
When created ``numnodes`` defines how many nodes are expected to
submit a collection, this is used to know when all nodes have
finished collection or how large the chunks need to be created.
Attributes:
:numnodes: The expected number of nodes taking part. The actual
number of nodes will vary during the scheduler's lifetime as
nodes are added by the DSession as they are brought up and
removed either because of a died node or normal shutdown. This
number is primarily used to know when the initial collection is
completed.
:node2collection: Map of nodes and their test collection. All
collections should always be identical.
:node2pending: Map of nodes and the indices of their pending
tests. The indices are an index into ``.pending`` (which is
identical to their own collection stored in
``.node2collection``).
:collection: The one collection once it is validated to be
identical between all the nodes. It is initialised to None
until ``.init_distribute()`` is called.
:pending: List of indices of globally pending tests. These are
tests which have not yet been allocated to a chunk for a node
to process.
:log: A py.log.Producer instance.
"""
def __init__(self, numnodes, log=None):
self.numnodes = numnodes
self.node2pending = {}
self.node2collection = {}
self.nodes = []
self.node2pending = {}
self.pending = []
self.collection = None
if log is None:
self.log = py.log.Producer("loadsched")
else:
self.log = log.loadsched
self.collection_is_completed = False
@property
def nodes(self):
"""A list of all nodes in the scheduler."""
return list(self.node2pending.keys())
@property
def collection_is_completed(self):
"""Boolean indication initial test collection is complete.
This is a boolean indicating all initial participating nodes
have finished collection. The required number of initial
nodes is defined by ``.numnodes``.
"""
return len(self.node2collection) >= self.numnodes
def haspending(self):
"""Return True if there are pending test items
This indicates that collection has finished and nodes are
still processing test items, so can be thought of as "the
scheduler is active".
"""
if self.pending:
return True
for pending in self.node2pending.values():
if pending:
return True
return False
def hasnodes(self):
"""Return True if nodes exist in the scheduler."""
return bool(self.node2pending)
def addnode(self, node):
"""Add a new node in the scheduler.
From now on the node will be allocated chunks of tests to
execute.
Called by the ``DSession.slave_slaveready`` hook when it
sucessfully bootstrapped a new node.
"""
assert node not in self.node2pending
self.node2pending[node] = []
self.nodes.append(node)
def tests_finished(self):
"""Return True if all tests have been executed by the nodes."""
if not self.collection_is_completed:
return False
if self.pending:
return False
for pending in self.node2pending.values():
if len(pending) >= 2:
return False
return True
def addnode_collection(self, node, collection):
assert not self.collection_is_completed
"""Add the collected test items from a node
The collection is stored in the ``.node2collection`` map.
Called by the ``DSession.slave_collectionfinish`` hook.
"""
assert node in self.node2pending
if self.collection_is_completed:
# A new node has been added later, perhaps an original one died.
assert self.collection # .init_distribute() should have
# been called by now
if collection != self.collection:
other_node = next(iter(self.node2collection.keys()))
msg = report_collection_diff(self.collection,
collection,
other_node.gateway.id,
node.gateway.id)
self.log(msg)
return
self.node2collection[node] = list(collection)
if len(self.node2collection) >= self.numnodes:
self.collection_is_completed = True
def remove_item(self, node, item_index, duration=0):
"""Mark test item as completed by node
The duration it took to execute the item is used as a hint to
the scheduler.
This is called by the ``DSession.slave_testreport`` hook.
"""
self.node2pending[node].remove(item_index)
self.check_schedule(node, duration=duration)
def check_schedule(self, node, duration=0):
"""Maybe schedule new items on the node
If there are any globally pending nodes left then this will
check if the given node should be given any more tests. The
``duration`` of the last test is optionally used as a
heuristic to influence how many tests the node is assigned.
"""
if self.pending:
# how many nodes do we have?
num_nodes = len(self.node2pending)
# if our node goes below a heuristic minimum, fill it out to
# heuristic maximum
items_per_node_min = max(
2, len(self.pending) // num_nodes // 4)
items_per_node_max = max(
2, len(self.pending) // num_nodes // 2)
items_per_node_min = max(2, len(self.pending) // num_nodes // 4)
items_per_node_max = max(2, len(self.pending) // num_nodes // 2)
node_pending = self.node2pending[node]
if len(node_pending) < items_per_node_min:
if duration >= 0.1 and len(node_pending) >= 2:
@@ -116,35 +224,59 @@ class LoadScheduling:
return
num_send = items_per_node_max - len(node_pending)
self._send_tests(node, num_send)
self.log("num items waiting for node:", len(self.pending))
#self.log("node2pending:", self.node2pending)
def remove_node(self, node):
self.nodes.remove(node)
"""Remove an node from the scheduler
This should be called either when the node crashed or at
shutdown time. In the former case any pending items assigned
to the node will be re-scheduled. Called by the
``DSession.slave_slavefinished`` and
``DSession.slave_errordown`` hooks.
Return the item which was being executing while the node
crashed or None if the node has no more pending items.
"""
pending = self.node2pending.pop(node)
if not pending:
return
# the node has crashed on the item if there are pending ones
# and we are told to remove the node
crashitem = self.collection[pending.pop(0)]
# put the remaining items back to the general pending list
# The node crashed, reassing pending items
crashitem = self.collection[pending.pop(0)]
self.pending.extend(pending)
# see if some nodes can pick the remaining tests up already
for node in self.node2pending:
self.check_schedule(node)
return crashitem
def init_distribute(self):
"""Initiate distribution of the test collection
Initiate scheduling of the items across the nodes. If this
gets called again later it behaves the same as calling
``.check_schedule()`` on all nodes so that newly added odes
will start to be used.
This is called by the ``DSession.slave_collectionfinish`` hook
if ``.collection_is_completed`` is True.
XXX Perhaps this method should have been called ".schedule()".
"""
assert self.collection_is_completed
# Initial distribution already happend, reschedule on all nodes
if self.collection is not None:
for node in self.nodes:
self.check_schedule(node)
return
# XXX allow nodes to have different collections
if not self._check_nodes_have_same_collection():
self.log('**Different tests collected, aborting run**')
return
# all collections are the same, good.
# we now create an index
# Collections are identical, create the index of pending items.
self.collection = list(self.node2collection.values())[0]
self.pending[:] = range(len(self.collection))
if not self.collection:
@@ -158,19 +290,18 @@ class LoadScheduling:
for node in self.nodes:
self._send_tests(node, node_chunksize)
#f = open("/tmp/sent", "w")
def _send_tests(self, node, num):
tests_per_node = self.pending[:num]
#print >>self.f, "sent", node, tests_per_node
if tests_per_node:
del self.pending[:num]
self.node2pending[node].extend(tests_per_node)
node.send_runtest_some(tests_per_node)
def _check_nodes_have_same_collection(self):
"""
Return True if all nodes have collected the same items, False otherwise.
This method also logs the collection differences as they are found.
"""Return True if all nodes have collected the same items.
If collections differ this returns False and logs the
collection differences as they are found.
"""
node_collection_items = list(self.node2collection.items())
first_node, col = node_collection_items[0]
@@ -216,7 +347,20 @@ def report_collection_diff(from_collection, to_collection, from_id, to_id):
class Interrupted(KeyboardInterrupt):
""" signals an immediate interruption. """
class DSession:
"""A py.test plugin which runs a distributed test session
At the beginning of the test session this creates a NodeManager
instance which creates and starts all nodes. Nodes then emit
events processed in the pytest_runtestloop hook using the slave_*
methods.
Once a node is started it will automatically start running the
py.test mainloop with some custom hooks. This means a node
automatically starts collecting tests. Once tests are collected
it will wait for instructions.
"""
def __init__(self, config):
self.config = config
self.log = py.log.Producer("dsession")
@@ -227,6 +371,7 @@ class DSession:
self.maxfail = config.getvalue("maxfail")
self.queue = queue.Queue()
self._failed_collection_errors = {}
self._active_nodes = set()
try:
self.terminal = config.pluginmanager.getplugin("terminalreporter")
except KeyError:
@@ -235,18 +380,33 @@ class DSession:
self.trdist = TerminalDistReporter(config)
config.pluginmanager.register(self.trdist, "terminaldistreporter")
@property
def session_finished(self):
"""Return True if the distributed session has finished
This means all nodes have executed all test items. This is
used to by pytest_runtestloop to break out of it's loop.
"""
return bool(self.shuttingdown and not self._active_nodes)
def report_line(self, line):
if self.terminal and self.config.option.verbose >= 0:
self.terminal.write_line(line)
@pytest.mark.trylast
def pytest_sessionstart(self, session):
"""Creates and starts the nodes.
The nodes are setup to put their events onto self.queue. As
soon as nodes start they will emit the slave_slaveready event.
"""
self.nodemanager = NodeManager(self.config)
self.nodemanager.setup_nodes(putevent=self.queue.put)
nodes = self.nodemanager.setup_nodes(putevent=self.queue.put)
self._active_nodes.update(nodes)
def pytest_sessionfinish(self, session):
""" teardown any resources after a test run. """
nm = getattr(self, 'nodemanager', None) # if not fully initialized
"""Shutdown all nodes."""
nm = getattr(self, 'nodemanager', None) # if not fully initialized
if nm is not None:
nm.teardown_nodes()
@@ -264,7 +424,6 @@ class DSession:
else:
assert 0, dist
self.shouldstop = False
self.session_finished = False
while not self.session_finished:
self.loop_once()
if self.shouldstop:
@@ -272,7 +431,7 @@ class DSession:
return True
def loop_once(self):
""" process one callback from one of the slaves. """
"""Process one callback from one of the slaves."""
while 1:
try:
eventcall = self.queue.get(timeout=2.0)
@@ -293,26 +452,40 @@ class DSession:
#
def slave_slaveready(self, node, slaveinfo):
"""Emitted when a node first starts up.
This adds the node to the scheduler, nodes continue with
collection without any further input.
"""
node.slaveinfo = slaveinfo
node.slaveinfo['id'] = node.gateway.id
node.slaveinfo['spec'] = node.gateway.spec
self.config.hook.pytest_testnodeready(node=node)
self.sched.addnode(node)
if self.shuttingdown:
node.shutdown()
else:
self.sched.addnode(node)
def slave_slavefinished(self, node):
"""Emitted when node executes its pytest_sessionfinish hook.
Removes the node from the scheduler.
The node might not be the scheduler if it had not emitted
slaveready before shutdown was triggered.
"""
self.config.hook.pytest_testnodedown(node=node, error=None)
if node.slaveoutput['exitstatus'] == 2: # keyboard-interrupt
if node.slaveoutput['exitstatus'] == 2: # keyboard-interrupt
self.shouldstop = "%s received keyboard-interrupt" % (node,)
self.slave_errordown(node, "keyboard-interrupt")
return
crashitem = self.sched.remove_node(node)
assert not crashitem, (crashitem, node)
if self.shuttingdown and not self.sched.hasnodes():
self.session_finished = True
if node in self.sched.nodes:
crashitem = self.sched.remove_node(node)
assert not crashitem, (crashitem, node)
self._active_nodes.remove(node)
def slave_errordown(self, node, error):
"""Emitted by the SlaveController when a node dies."""
self.config.hook.pytest_testnodedown(node=node, error=error)
try:
crashitem = self.sched.remove_node(node)
@@ -321,41 +494,70 @@ class DSession:
else:
if crashitem:
self.handle_crashitem(crashitem, node)
#self.report_line("item crashed on node: %s" % crashitem)
if not self.sched.hasnodes():
self.session_finished = True
self.report_line("Replacing failed node %s" % node.gateway.id)
self._clone_node(node)
self._active_nodes.remove(node)
def slave_collectionfinish(self, node, ids):
"""Slave has finished test collection.
This adds the collection for this node to the scheduler. If
the scheduler indicates collection is finished (i.e. all
initial nodes have submitted their collection), then tells the
scheduler to schedule the collected items. When initiating
scheduling the first time it logs which scheduler is in use.
"""
if self.shuttingdown:
return
self.sched.addnode_collection(node, ids)
if self.terminal:
self.trdist.setstatus(node.gateway.spec, "[%d]" %(len(ids)))
self.trdist.setstatus(node.gateway.spec, "[%d]" % (len(ids)))
if self.sched.collection_is_completed:
if self.terminal:
if self.terminal and not self.sched.haspending():
self.trdist.ensure_show_status()
self.terminal.write_line("")
self.terminal.write_line("scheduling tests via %s" %(
self.terminal.write_line("scheduling tests via %s" % (
self.sched.__class__.__name__))
self.sched.init_distribute()
def slave_logstart(self, node, nodeid, location):
"""Emitted when a node calls the pytest_runtest_logstart hook."""
self.config.hook.pytest_runtest_logstart(
nodeid=nodeid, location=location)
def slave_testreport(self, node, rep):
if not (rep.passed and rep.when != "call"):
if rep.when in ("setup", "call"):
self.sched.remove_item(node, rep.item_index, rep.duration)
"""Emitted when a node calls the pytest_runtest_logreport hook.
If the node indicates it is finished with a test item remove
the item from the pending list in the scheduler.
"""
if rep.when == "call" or (rep.when == "setup" and not rep.passed):
self.sched.remove_item(node, rep.item_index, rep.duration)
#self.report_line("testreport %s: %s" %(rep.id, rep.status))
rep.node = node
self.config.hook.pytest_runtest_logreport(report=rep)
self._handlefailures(rep)
def slave_collectreport(self, node, rep):
"""Emitted when a node calls the pytest_collectreport hook."""
if rep.failed:
self._failed_slave_collectreport(node, rep)
def _clone_node(self, node):
"""Return new node based on an existing one.
This is normally for when a node died, this will copy the spec
of the existing node and create a new one with a new id. The
new node will have been setup so will start calling the
"slave_*" hooks and do work soon.
"""
spec = node.gateway.spec
spec.id = None
self.nodemanager.group.allocate_id(spec)
node = self.nodemanager.setup_node(spec, self.queue.put)
self._active_nodes.add(node)
return node
def _failed_slave_collectreport(self, node, rep):
# Check we haven't already seen this report (from
# another slave).
@@ -374,19 +576,21 @@ class DSession:
def triggershutdown(self):
self.log("triggering shutdown")
self.shuttingdown = True
for node in self.sched.node2pending:
for node in self.sched.nodes:
node.shutdown()
def handle_crashitem(self, nodeid, slave):
# XXX get more reporting info by recording pytest_runtest_logstart?
# XXX count no of failures and retry N times
runner = self.config.pluginmanager.getplugin("runner")
fspath = nodeid.split("::")[0]
msg = "Slave %r crashed while running %r" %(slave.gateway.id, nodeid)
rep = runner.TestReport(nodeid, (fspath, None, fspath), (),
"failed", msg, "???")
msg = "Slave %r crashed while running %r" % (slave.gateway.id, nodeid)
rep = runner.TestReport(nodeid, (fspath, None, fspath),
(), "failed", msg, "???")
rep.node = slave
self.config.hook.pytest_runtest_logreport(report=rep)
class TerminalDistReporter:
def __init__(self, config):
self.config = config