Joshua M. Boniface
f248d579df
Also fixes up the Debian packaging such that this works how I would want, with proper module installation while leaving everything else untouched. Finally implements automatic installation and removal of the BASH completion for the PVC command.
103 lines
2.8 KiB
Python
103 lines
2.8 KiB
Python
#!/usr/bin/env python3
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# zkhandler.py - Secure versioned ZooKeeper updates
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# Part of the Parallel Virtual Cluster (PVC) system
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#
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# Copyright (C) 2018-2021 Joshua M. Boniface <joshua@boniface.me>
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#
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation, version 3.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program. If not, see <https://www.gnu.org/licenses/>.
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#
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###############################################################################
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import uuid
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# Exists function
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def exists(zk_conn, key):
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stat = zk_conn.exists(key)
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if stat:
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return True
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else:
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return False
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# Child list function
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def listchildren(zk_conn, key):
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children = zk_conn.get_children(key)
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return children
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# Delete key function
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def deletekey(zk_conn, key, recursive=True):
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zk_conn.delete(key, recursive=recursive)
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# Data read function
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def readdata(zk_conn, key):
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data_raw = zk_conn.get(key)
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data = data_raw[0].decode('utf8')
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return data
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# Data write function
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def writedata(zk_conn, kv):
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# Start up a transaction
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zk_transaction = zk_conn.transaction()
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# Proceed one KV pair at a time
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for key in sorted(kv):
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data = kv[key]
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# Check if this key already exists or not
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if not zk_conn.exists(key):
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# We're creating a new key
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zk_transaction.create(key, str(data).encode('utf8'))
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else:
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# We're updating a key with version validation
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orig_data = zk_conn.get(key)
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version = orig_data[1].version
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# Set what we expect the new version to be
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new_version = version + 1
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# Update the data
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zk_transaction.set_data(key, str(data).encode('utf8'))
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# Set up the check
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try:
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zk_transaction.check(key, new_version)
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except TypeError:
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print('Zookeeper key "{}" does not match expected version'.format(key))
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return False
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# Commit the transaction
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try:
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zk_transaction.commit()
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return True
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except Exception:
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return False
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# Write lock function
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def writelock(zk_conn, key):
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lock_id = str(uuid.uuid1())
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lock = zk_conn.WriteLock('{}'.format(key), lock_id)
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return lock
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# Read lock function
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def readlock(zk_conn, key):
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lock_id = str(uuid.uuid1())
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lock = zk_conn.ReadLock('{}'.format(key), lock_id)
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return lock
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