61 lines
2.1 KiB
Python
61 lines
2.1 KiB
Python
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#!/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 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, either version 3 of the License, or
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# (at your option) any later version.
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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 kazoo.client
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import pvcd.ansiiprint as ansiiprint
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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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# 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('ascii')
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meta = data_raw[1]
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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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# Get the current version; we base this off the first key (ordering in multi-key calls is irrelevant)
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first_key = list(kv.keys())[0]
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orig_data_raw = zk_conn.get(first_key)
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meta = orig_data_raw[1]
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if meta == None:
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ansiiprint.echo('Zookeeper key "{}" does not exist'.format(first_key), '', 'e')
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return 1
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version = meta.version
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new_version = version + 1
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zk_transaction = zk_conn.transaction()
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for key, data in kv.items():
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zk_transaction.set_data(key, data.encode('ascii'))
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try:
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zk_transaction.check(first_key, new_version)
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except TypeError:
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ansiiprint.echo('Zookeeper key "{}" does not match expected version'.format(first_key), '', 'e')
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return 1
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zk_transaction.commit()
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return 0
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