mirror of
https://github.com/sqlalchemy/sqlalchemy.git
synced 2026-05-29 12:06:28 -04:00
Mike Bayer
88 lines
2.3 KiB
Python
88 lines
2.3 KiB
Python
"""environment.py
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Establish data / cache file paths, and configurations,
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bootstrap fixture data if necessary.
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"""
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from . import caching_query
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from sqlalchemy import create_engine
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from sqlalchemy.orm import scoped_session, sessionmaker
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from sqlalchemy.ext.declarative import declarative_base
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from dogpile.cache.region import make_region
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import os
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from hashlib import md5
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import sys
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py2k = sys.version_info < (3, 0)
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if py2k:
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input = raw_input
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# dogpile cache regions. A home base for cache configurations.
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regions = {}
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# scoped_session. Apply our custom CachingQuery class to it,
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# using a callable that will associate the dictionary
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# of regions with the Query.
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Session = scoped_session(
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sessionmaker(
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query_cls=caching_query.query_callable(regions)
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)
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)
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# global declarative base class.
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Base = declarative_base()
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root = "./dogpile_data/"
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if not os.path.exists(root):
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input("Will create datafiles in %r.\n"
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"To reset the cache + database, delete this directory.\n"
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"Press enter to continue.\n" % root
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)
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os.makedirs(root)
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dbfile = os.path.join(root, "dogpile_demo.db")
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engine = create_engine('sqlite:///%s' % dbfile, echo=True)
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Session.configure(bind=engine)
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def md5_key_mangler(key):
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"""Receive cache keys as long concatenated strings;
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distill them into an md5 hash.
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"""
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return md5(key.encode('ascii')).hexdigest()
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# configure the "default" cache region.
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regions['default'] = make_region(
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# the "dbm" backend needs
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# string-encoded keys
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key_mangler=md5_key_mangler
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).configure(
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# using type 'file' to illustrate
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# serialized persistence. Normally
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# memcached or similar is a better choice
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# for caching.
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'dogpile.cache.dbm',
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expiration_time=3600,
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arguments={
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"filename": os.path.join(root, "cache.dbm")
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}
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)
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# optional; call invalidate() on the region
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# once created so that all data is fresh when
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# the app is restarted. Good for development,
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# on a production system needs to be used carefully
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# regions['default'].invalidate()
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installed = False
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def bootstrap():
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global installed
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from . import fixture_data
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if not os.path.exists(dbfile):
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fixture_data.install()
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installed = True |