91 lines
2.7 KiB
Python
91 lines
2.7 KiB
Python
#!/usr/bin/env python3
|
|
|
|
# zkhandler.py - Secure versioned ZooKeeper updates
|
|
# Part of the Parallel Virtual Cluster (PVC) system
|
|
#
|
|
# Copyright (C) 2018 Joshua M. Boniface <joshua@boniface.me>
|
|
#
|
|
# This program is free software: you can redistribute it and/or modify
|
|
# it under the terms of the GNU General Public License as published by
|
|
# the Free Software Foundation, either version 3 of the License, or
|
|
# (at your option) any later version.
|
|
#
|
|
# This program 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 General Public License for more details.
|
|
#
|
|
# You should have received a copy of the GNU General Public License
|
|
# along with this program. If not, see <https://www.gnu.org/licenses/>.
|
|
#
|
|
###############################################################################
|
|
|
|
import kazoo.client
|
|
import client_lib.ansiprint as ansiprint
|
|
|
|
# Exists function
|
|
def exists(zk_conn, key):
|
|
stat = zk_conn.exists(key)
|
|
if stat is None:
|
|
return False
|
|
else:
|
|
return True
|
|
|
|
# Child list function
|
|
def listchildren(zk_conn, key):
|
|
children = zk_conn.get_children(key)
|
|
return children
|
|
|
|
# Delete key function
|
|
def deletekey(zk_conn, key, recursive=True):
|
|
try:
|
|
zk_conn.delete(key, recursive=recursive)
|
|
except:
|
|
pass
|
|
|
|
# Data read function
|
|
def readdata(zk_conn, key):
|
|
data_raw = zk_conn.get(key)
|
|
data = data_raw[0].decode('ascii')
|
|
meta = data_raw[1]
|
|
return data
|
|
|
|
# Data write function
|
|
def writedata(zk_conn, kv):
|
|
# Start up a transaction
|
|
zk_transaction = zk_conn.transaction()
|
|
|
|
# Proceed one KV pair at a time
|
|
for key in sorted(kv):
|
|
data = kv[key]
|
|
|
|
# Check if this key already exists or not
|
|
if not zk_conn.exists(key):
|
|
# We're creating a new key
|
|
zk_transaction.create(key, str(data).encode('ascii'))
|
|
else:
|
|
# We're updating a key with version validation
|
|
orig_data = zk_conn.get(key)
|
|
version = orig_data[1].version
|
|
|
|
# Set what we expect the new version to be
|
|
new_version = version + 1
|
|
|
|
# Update the data
|
|
zk_transaction.set_data(key, str(data).encode('ascii'))
|
|
|
|
# Set up the check
|
|
try:
|
|
zk_transaction.check(key, new_version)
|
|
except TypeError:
|
|
print('Zookeeper key "{}" does not match expected version'.format(key))
|
|
return False
|
|
|
|
# Commit the transaction
|
|
try:
|
|
zk_transaction.commit()
|
|
return True
|
|
except Exception:
|
|
return False
|
|
|