ceph/teuthology/locker/api.py
Josh Durgin b1a0c1adea locker: fix race in locking
The isolation level is lower than I thought. This made it possible for
two clients to think they both locked the same machines, since the
update would still be modifying each row to change the locked_since
time.
2011-11-03 11:29:18 -07:00

113 lines
4.0 KiB
Python

import json
import web
from config import DB
def load_machine(name):
results = list(DB.select('machine', what='*',
where='name = $name',
vars=dict(name=name)))
if not results:
raise web.NotFound()
return results[0]
class MachineLock:
def GET(self, name):
row = load_machine(name)
row.locked_since = row.locked_since.isoformat()
web.header('Content-type', 'text/json')
return json.dumps(row)
def DELETE(self, name):
user = web.input('user')['user']
machine = load_machine(name)
if not machine.locked:
raise web.BadRequest()
if machine.locked_by != user:
raise web.Forbidden()
res = DB.update('machine',
where='locked = true AND name = $name AND locked_by = $user',
vars=dict(name=name, user=user),
locked=False, locked_by=None)
assert res == 1, 'Failed to unlock machine {name}'.format(name=name)
def POST(self, name):
user = web.input('user')['user']
machine = load_machine(name)
if machine.locked:
raise web.Forbidden()
res = DB.update('machine', where='name = $name AND locked = false',
vars=dict(name=name),
locked=True,
locked_by=user,
locked_since=web.db.SQLLiteral('NOW()'))
assert res == 1, 'Failed to lock machine {name}'.format(name=name)
def PUT(self, name):
desc = web.input(desc=None)['desc']
status = web.input(status=None)['status']
sshpubkey = web.input(sshpubkey=None)['sshpubkey']
updated = {}
if desc is not None:
updated['description'] = desc
if status is not None:
updated['up'] = (status == 'up')
if sshpubkey is not None:
updated['sshpubkey'] = sshpubkey
if not updated:
raise web.BadRequest()
DB.update('machine', where='name = $name',
vars=dict(name=name), **updated)
class Lock:
def GET(self):
rows = list(DB.select('machine', what='*'))
if not rows:
raise web.NotFound()
for row in rows:
row.locked_since = row.locked_since.isoformat()
web.header('Content-type', 'text/json')
return json.dumps(rows)
def POST(self):
user = web.input('user')['user']
num = int(web.input('num')['num'])
if num < 1:
raise web.BadRequest()
tries = 0
while True:
try:
# transaction will be rolled back if an exception is raised
with DB.transaction():
results = list(DB.select('machine', what='name, sshpubkey',
where='locked = false AND up = true',
limit=num))
if len(results) < num:
raise web.HTTPError(status='503 Service Unavailable')
name_keys = {}
for row in results:
name_keys[row.name] = row.sshpubkey
where_cond = web.db.sqlors('name = ', name_keys.keys()) \
+ ' AND locked = false AND up = true'
num_locked = DB.update('machine',
where=where_cond,
locked=True,
locked_by=user,
locked_since=web.db.SQLLiteral('NOW()'))
assert num_locked == num, 'Failed to lock machines'
except:
tries += 1
if tries < 10:
continue
raise
else:
break
web.header('Content-type', 'text/json')
return json.dumps(name_keys)