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use futures to avoid races on slow spawners

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trigger events by hand so that performance can't cause races
This commit is contained in:
Min RK
2017-08-03 11:45:29 +02:00
parent 088fdc8f42
commit 329781023f
2 changed files with 21 additions and 9 deletions
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9
jupyterhub/tests/mocking.py
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@@ -62,15 +62,20 @@ class MockSpawner(LocalProcessSpawner):
class SlowSpawner(MockSpawner): class SlowSpawner(MockSpawner):
"""A spawner that takes a few seconds to start""" """A spawner that takes a few seconds to start"""
delay = 2
_start_future = None
@gen.coroutine @gen.coroutine
def start(self): def start(self):
(ip, port) = yield super().start() (ip, port) = yield super().start()
yield gen.sleep(2) if self._start_future is not None:
yield self._start_future
else:
yield gen.sleep(self.delay)
return ip, port return ip, port
@gen.coroutine @gen.coroutine
def stop(self): def stop(self):
yield gen.sleep(2) yield gen.sleep(self.delay)
yield super().stop() yield super().stop()

15
jupyterhub/tests/test_api.py
View File

@@ -1,5 +1,6 @@
"""Tests for the REST API.""" """Tests for the REST API."""
from concurrent.futures import Future
import json import json
import time import time
import sys import sys
@@ -554,34 +555,40 @@ def test_spawn_limit(app, no_patience, slow_spawn, request):
# start two pending spawns # start two pending spawns
names = ['ykka', 'hjarka'] names = ['ykka', 'hjarka']
users = [ add_user(db, app=app, name=name) for name in names ] users = [ add_user(db, app=app, name=name) for name in names ]
users[0].spawner._start_future = Future()
users[1].spawner._start_future = Future()
for name in names: for name in names:
yield api_request(app, 'users', name, 'server', method='post') yield api_request(app, 'users', name, 'server', method='post')
yield gen.sleep(0.5)
assert app.users.count_active_users()['pending'] == 2 assert app.users.count_active_users()['pending'] == 2
# ykka and hjarka's spawns are pending. Essun should fail with 429 # ykka and hjarka's spawns are both pending. Essun should fail with 429
name = 'essun' name = 'essun'
user = add_user(db, app=app, name=name) user = add_user(db, app=app, name=name)
user.spawner._start_future = Future()
r = yield api_request(app, 'users', name, 'server', method='post') r = yield api_request(app, 'users', name, 'server', method='post')
assert r.status_code == 429 assert r.status_code == 429
# allow ykka to start
users[0].spawner._start_future.set_result(None)
# wait for ykka to finish # wait for ykka to finish
while not users[0].running: while not users[0].running:
yield gen.sleep(0.1) yield gen.sleep(0.1)
# race? hjarka could finish in this time
# come back to this if we see intermittent failures here
assert app.users.count_active_users()['pending'] == 1 assert app.users.count_active_users()['pending'] == 1
r = yield api_request(app, 'users', name, 'server', method='post') r = yield api_request(app, 'users', name, 'server', method='post')
r.raise_for_status() r.raise_for_status()
assert app.users.count_active_users()['pending'] == 2 assert app.users.count_active_users()['pending'] == 2
users.append(user) users.append(user)
# allow hjarka and essun to finish starting
for user in users[1:]:
user.spawner._start_future.set_result(None)
while not all(u.running for u in users): while not all(u.running for u in users):
yield gen.sleep(0.1) yield gen.sleep(0.1)
# everybody's running, pending count should be back to 0 # everybody's running, pending count should be back to 0
assert app.users.count_active_users()['pending'] == 0 assert app.users.count_active_users()['pending'] == 0
for u in users: for u in users:
u.spawner.delay = 0
r = yield api_request(app, 'users', u.name, 'server', method='delete') r = yield api_request(app, 'users', u.name, 'server', method='delete')
yield r.raise_for_status() yield r.raise_for_status()
while any(u.spawner.active for u in users): while any(u.spawner.active for u in users):