0001-utils-add-defer-module-to-run-things-later-31204.patch
passerelle/utils/defer.py | ||
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# Copyright (C) 2019 Entr'ouvert |
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# |
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# This program is free software: you can redistribute it and/or modify it |
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# under the terms of the GNU Affero General Public License as published |
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# by 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 Affero General Public License for more details. |
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# |
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# You should have received a copy of the GNU Affero General Public License |
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# along with this program. If not, see <http://www.gnu.org/licenses/>. |
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import functools |
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import logging |
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import threading |
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import django.db |
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class DeferrableBarrier(threading.local): |
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@property |
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def stack(self): |
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if not hasattr(self, '_stack'): |
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self._stack = [] |
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return self._stack |
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def __push(self): |
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self.stack.append([]) |
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def defer(self, func, *args, **kwargs): |
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if self.should_defer: |
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self.stack[-1].append((func, args, kwargs)) |
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else: |
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return func(*args, **kwargs) |
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def __pop(self): |
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return self.stack.pop() |
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def __enter__(self): |
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self.__push() |
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return self |
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def __exit__(self, exc_type, exc_value, exc_tb): |
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for func, args, kwargs in self.__pop(): |
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try: |
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func(*args, **kwargs) |
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except Exception: |
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logging.exception('failed to run deferrable function %s', func) |
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@property |
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def should_defer(self): |
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return bool(self.stack) |
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def deferrable(self, func=None, predicate=None): |
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'''Automatically defer a function if dynamic scope is inside a deferrable_barrier.''' |
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if not func: |
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return functools.partial(self.deferrable, predicate=predicate) |
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@functools.wraps(func) |
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def f(*args, **kwargs): |
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if not predicate or predicate(): |
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return self.defer(func, *args, **kwargs) |
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else: |
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return func(*args, **kwargs) |
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return f |
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def __call__(self, func): |
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'''Wraps func in a deferrable_barrier scope.''' |
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@functools.wraps(func) |
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def f(*args, **kwargs): |
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with self: |
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return func(*args, **kwargs) |
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return f |
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deferrable_barrier = DeferrableBarrier() |
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def is_in_transaction(): |
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return getattr(django.db.connection, 'in_atomic_block', False) |
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deferrable = deferrable_barrier.deferrable |
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deferrable_if_in_transaction = deferrable_barrier.deferrable(predicate=is_in_transaction) |
tests/test_defer.py | ||
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# Copyright (C) 2019 Entr'ouvert |
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2 |
# |
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# This program is free software: you can redistribute it and/or modify it |
|
4 |
# under the terms of the GNU Affero General Public License as published |
|
5 |
# by the Free Software Foundation, either version 3 of the License, or |
|
6 |
# (at your option) any later version. |
|
7 |
# |
|
8 |
# This program is distributed in the hope that it will be useful, |
|
9 |
# but WITHOUT ANY WARRANTY; without even the implied warranty of |
|
10 |
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
|
11 |
# GNU Affero General Public License for more details. |
|
12 |
# |
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# You should have received a copy of the GNU Affero General Public License |
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# along with this program. If not, see <http://www.gnu.org/licenses/>. |
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import threading |
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from django.db import transaction |
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from passerelle.utils import defer |
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import pytest |
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def test_deferrable_barrier(): |
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x = [] |
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def f(): |
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x.append(1) |
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assert not defer.deferrable_barrier.should_defer |
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with defer.deferrable_barrier: |
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assert defer.deferrable_barrier.should_defer |
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defer.deferrable_barrier.defer(f) |
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assert x == [] |
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assert not defer.deferrable_barrier.should_defer |
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assert x == [1] |
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def test_deferrable_barrier_with_threading(): |
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x = [] |
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def f(): |
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x.append(1) |
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assert not defer.deferrable_barrier.should_defer |
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with defer.deferrable_barrier: |
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defer.deferrable_barrier.defer(f) |
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assert x == [] |
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t = threading.Thread(target=defer.deferrable_barrier.defer, args=(f,)) |
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assert x == [] |
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t.start() |
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t.join() |
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assert x == [1] |
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assert not defer.deferrable_barrier.should_defer |
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assert x == [1, 1] |
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def test_deferrable(): |
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x = [] |
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@defer.deferrable |
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def f(): |
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x.append(1) |
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f() |
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assert x == [1] |
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assert not defer.deferrable_barrier.should_defer |
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with defer.deferrable_barrier: |
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f() |
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assert x == [1] |
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assert not defer.deferrable_barrier.should_defer |
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assert x == [1, 1] |
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def test_deferrable_with_threading(): |
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x = [] |
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@defer.deferrable |
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def f(): |
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x.append(1) |
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f() |
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assert x == [1] |
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assert not defer.deferrable_barrier.should_defer |
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with defer.deferrable_barrier: |
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f() |
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assert x == [1] |
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t = threading.Thread(target=f) |
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t.start() |
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t.join() |
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assert x == [1, 1] |
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assert x == [1, 1, 1] |
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assert not defer.deferrable_barrier.should_defer |
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def test_deferrable_if_in_transaction(transactional_db): |
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assert not defer.is_in_transaction() |
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x = [] |
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@defer.deferrable_if_in_transaction |
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def f(): |
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x.append(1) |
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f() |
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assert x == [1] |
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with transaction.atomic(): |
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assert defer.is_in_transaction() |
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f() |
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assert x == [1, 1] |
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with pytest.raises(Exception): |
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with defer.deferrable_barrier: |
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f() |
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assert x == [1, 1, 1] |
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try: |
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with transaction.atomic(): |
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f() |
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assert x == [1, 1, 1] |
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raise Exception |
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finally: |
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assert x == [1, 1, 1] |
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assert x == [1, 1, 1, 1] |
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0 |
- |