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73 lines
1.9 KiB
Python
73 lines
1.9 KiB
Python
from contextlib import contextmanager
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from redis import Redis
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from .local import LocalStack, release_local
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class NoRedisConnectionException(Exception):
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pass
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@contextmanager
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def Connection(connection=None):
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if connection is None:
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connection = Redis()
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push_connection(connection)
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try:
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yield
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finally:
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popped = pop_connection()
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assert popped == connection, \
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'Unexpected Redis connection was popped off the stack. ' \
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'Check your Redis connection setup.'
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def push_connection(redis):
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"""Pushes the given connection on the stack."""
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_connection_stack.push(redis)
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def pop_connection():
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"""Pops the topmost connection from the stack."""
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return _connection_stack.pop()
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def use_connection(redis=None):
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"""Clears the stack and uses the given connection. Protects against mixed
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use of use_connection() and stacked connection contexts.
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"""
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assert len(_connection_stack) <= 1, \
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'You should not mix Connection contexts with use_connection().'
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release_local(_connection_stack)
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if redis is None:
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redis = Redis()
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push_connection(redis)
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def get_current_connection():
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"""Returns the current Redis connection (i.e. the topmost on the
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connection stack).
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"""
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return _connection_stack.top
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def resolve_connection(connection=None):
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"""Convenience function to resolve the given or the current connection.
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Raises an exception if it cannot resolve a connection now.
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"""
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if connection is not None:
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return connection
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connection = get_current_connection()
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if connection is None:
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raise NoRedisConnectionException(
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'Could not resolve a Redis connection.')
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return connection
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_connection_stack = LocalStack()
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__all__ = ['Connection',
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'get_current_connection', 'push_connection', 'pop_connection',
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'use_connection']
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