root / snf-pithos-backend / pithos / backends / lib / sqlalchemy / config.py @ 6a5ca445
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1 | 6540c590 | Sofia Papagiannaki | # Copyright 2011-2012 GRNET S.A. All rights reserved.
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2 | 6540c590 | Sofia Papagiannaki | #
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3 | 6540c590 | Sofia Papagiannaki | # Redistribution and use in source and binary forms, with or
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4 | 6540c590 | Sofia Papagiannaki | # without modification, are permitted provided that the following
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5 | 6540c590 | Sofia Papagiannaki | # conditions are met:
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6 | 6540c590 | Sofia Papagiannaki | #
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7 | 6540c590 | Sofia Papagiannaki | # 1. Redistributions of source code must retain the above
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8 | 6540c590 | Sofia Papagiannaki | # copyright notice, this list of conditions and the following
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9 | 6540c590 | Sofia Papagiannaki | # disclaimer.
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10 | 6540c590 | Sofia Papagiannaki | #
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11 | 6540c590 | Sofia Papagiannaki | # 2. Redistributions in binary form must reproduce the above
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12 | 6540c590 | Sofia Papagiannaki | # copyright notice, this list of conditions and the following
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13 | 6540c590 | Sofia Papagiannaki | # disclaimer in the documentation and/or other materials
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14 | 6540c590 | Sofia Papagiannaki | # provided with the distribution.
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15 | 6540c590 | Sofia Papagiannaki | #
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16 | 6540c590 | Sofia Papagiannaki | # THIS SOFTWARE IS PROVIDED BY GRNET S.A. ``AS IS'' AND ANY EXPRESS
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17 | 6540c590 | Sofia Papagiannaki | # OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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18 | 6540c590 | Sofia Papagiannaki | # WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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19 | 6540c590 | Sofia Papagiannaki | # PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL GRNET S.A OR
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20 | 6540c590 | Sofia Papagiannaki | # CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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21 | 6540c590 | Sofia Papagiannaki | # SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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25 | 6540c590 | Sofia Papagiannaki | # LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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26 | 6540c590 | Sofia Papagiannaki | # ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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27 | 6540c590 | Sofia Papagiannaki | # POSSIBILITY OF SUCH DAMAGE.
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28 | 6540c590 | Sofia Papagiannaki | #
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29 | 6540c590 | Sofia Papagiannaki | # The views and conclusions contained in the software and
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30 | 6540c590 | Sofia Papagiannaki | # documentation are those of the authors and should not be
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31 | 6540c590 | Sofia Papagiannaki | # interpreted as representing official policies, either expressed
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32 | 6540c590 | Sofia Papagiannaki | # or implied, of GRNET S.A.
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33 | 6540c590 | Sofia Papagiannaki | |
34 | 6540c590 | Sofia Papagiannaki | from sqlalchemy import Table, Column, String, MetaData |
35 | 6540c590 | Sofia Papagiannaki | from sqlalchemy.sql import select |
36 | 6540c590 | Sofia Papagiannaki | from sqlalchemy.exc import NoSuchTableError |
37 | 6540c590 | Sofia Papagiannaki | |
38 | 6540c590 | Sofia Papagiannaki | from dbworker import DBWorker |
39 | 6540c590 | Sofia Papagiannaki | |
40 | 6540c590 | Sofia Papagiannaki | def create_tables(engine): |
41 | 6540c590 | Sofia Papagiannaki | metadata = MetaData() |
42 | 6540c590 | Sofia Papagiannaki | columns = [] |
43 | 6540c590 | Sofia Papagiannaki | columns.append(Column('key', String(256), primary_key=True)) |
44 | 6540c590 | Sofia Papagiannaki | columns.append(Column('value', String(256))) |
45 | 6540c590 | Sofia Papagiannaki | config = Table('config', metadata, *columns, mysql_engine='InnoDB') |
46 | 6540c590 | Sofia Papagiannaki | |
47 | 6540c590 | Sofia Papagiannaki | metadata.create_all(engine) |
48 | 6540c590 | Sofia Papagiannaki | return metadata.sorted_tables
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49 | 6540c590 | Sofia Papagiannaki | |
50 | 6540c590 | Sofia Papagiannaki | class Config(DBWorker): |
51 | 6540c590 | Sofia Papagiannaki | """Config are properties holding persistent information about system state.
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52 | 6540c590 | Sofia Papagiannaki | """
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53 | 6540c590 | Sofia Papagiannaki | |
54 | 6540c590 | Sofia Papagiannaki | def __init__(self, **params): |
55 | 6540c590 | Sofia Papagiannaki | DBWorker.__init__(self, **params)
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56 | 6540c590 | Sofia Papagiannaki | try:
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57 | 6540c590 | Sofia Papagiannaki | metadata = MetaData(self.engine)
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58 | 6540c590 | Sofia Papagiannaki | self.config = Table('config', metadata, autoload=True) |
59 | 6540c590 | Sofia Papagiannaki | except NoSuchTableError:
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60 | 6540c590 | Sofia Papagiannaki | tables = create_tables(self.engine)
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61 | 6540c590 | Sofia Papagiannaki | map(lambda t: self.__setattr__(t.name, t), tables) |
62 | 6540c590 | Sofia Papagiannaki | |
63 | 6540c590 | Sofia Papagiannaki | def get_value(self, key): |
64 | 6540c590 | Sofia Papagiannaki | """Return configuration value for key."""
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65 | 6540c590 | Sofia Papagiannaki | |
66 | 6540c590 | Sofia Papagiannaki | s = select([self.config.c.value])
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67 | 6540c590 | Sofia Papagiannaki | s = s.where(self.config.c.key == key)
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68 | 6540c590 | Sofia Papagiannaki | r = self.conn.execute(s)
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69 | 6540c590 | Sofia Papagiannaki | row = r.fetchone() |
70 | 6540c590 | Sofia Papagiannaki | r.close() |
71 | 6540c590 | Sofia Papagiannaki | if row:
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72 | 6540c590 | Sofia Papagiannaki | return row[0] |
73 | 6540c590 | Sofia Papagiannaki | return None |
74 | 6540c590 | Sofia Papagiannaki | |
75 | 6540c590 | Sofia Papagiannaki | def set_value(self, key, value): |
76 | 6540c590 | Sofia Papagiannaki | """Set a configuration entry.
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77 | 6540c590 | Sofia Papagiannaki | """
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78 | 6540c590 | Sofia Papagiannaki | |
79 | 6540c590 | Sofia Papagiannaki | s = self.config.insert()
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80 | 6540c590 | Sofia Papagiannaki | r = self.conn.execute(s, key=key, value=value)
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81 | 6540c590 | Sofia Papagiannaki | inserted_primary_key = r.inserted_primary_key[0]
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82 | 6540c590 | Sofia Papagiannaki | r.close() |
83 | 6540c590 | Sofia Papagiannaki | return inserted_primary_key |