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Add some thread safety tests

We don't actually use nilmdb.utils.threadsafety.verify_proxy in the
main NilmDB code, but it's useful for finding errors.

It found an issue with __getattr__ in SerializerProxy which
(1) can't be avoided?
(2) is now commented in the code
(3) shouldn't matter in real use
tags/nilmdb-2.0.0
Jim Paris 2 years ago
parent
commit
544413018c
4 changed files with 37 additions and 33 deletions
  1. +15
    -2
      nilmdb/utils/serializer.py
  2. +11
    -23
      nilmdb/utils/threadsafety.py
  3. +3
    -0
      tests/test_serializer.py
  4. +8
    -8
      tests/test_threadsafety.py

+ 15
- 2
nilmdb/utils/serializer.py View File

@@ -79,12 +79,25 @@ def serializer_proxy(obj_or_type):
self._thread_safe = True

def __getattr__(self, key):
# If the attribute is a function, we want to return a
# proxy that will perform the call through the serializer
# when called. Otherwise, we want to return the value
# directly. This means we need to grab the attribute once,
# and therefore self.__object.__getattr__ may be called
# in an unsafe way, from the caller's thread.
attr = getattr(self.__object, key)
if not callable(attr):
# It's not callable, so perform the getattr from within
# the serializer thread, then return its value.
# That may differ from the "attr" value we just grabbed
# from here, due to forced ordering in the serializer.
getter = SerializerCallProxy(self.__call_queue, getattr, self)
return getter(self.__object, key)
r = SerializerCallProxy(self.__call_queue, attr, self)
return r
else:
# It is callable, so return an object that will proxy through
# the serializer when called.
r = SerializerCallProxy(self.__call_queue, attr, self)
return r

# For an interable object, on __iter__(), save the object's
# iterator and return this proxy. On next(), call the object's


+ 11
- 23
nilmdb/utils/threadsafety.py View File

@@ -3,19 +3,18 @@ import threading
import warnings
import types

def verify_proxy(obj_or_type, exception = False, check_thread = True,
def verify_proxy(obj_or_type, check_thread = True,
check_concurrent = True):
"""Wrap the given object or type in a VerifyObjectProxy.

Returns a VerifyObjectProxy that proxies all method calls to the
given object, as well as attribute retrievals.

When calling methods, the following checks are performed. If
exception is True, an exception is raised. Otherwise, a warning
is printed.
When calling methods, the following checks are performed. On
failure, an exception is raised.

check_thread = True # Warn/fail if two different threads call methods.
check_concurrent = True # Warn/fail if two functions are concurrently
check_thread = True # Fail if two different threads call methods.
check_concurrent = True # Fail if two functions are concurrently
# run through this proxy
"""
class Namespace(object):
@@ -42,10 +41,7 @@ def verify_proxy(obj_or_type, exception = False, check_thread = True,
" but %s called %s.%s",
p.thread.name, p.classname, p.thread_callee,
this.name, p.classname, callee)
if exception:
raise AssertionError(err)
else: # pragma: no cover
warnings.warn(err)
raise AssertionError(err)

need_concur_unlock = False
if check_concurrent:
@@ -54,10 +50,7 @@ def verify_proxy(obj_or_type, exception = False, check_thread = True,
"while %s is still in %s.%s",
this.name, p.classname, callee,
p.concur_tname, p.classname, p.concur_callee)
if exception:
raise AssertionError(err)
else: # pragma: no cover
warnings.warn(err)
raise AssertionError(err)
else:
p.concur_tname = this.name
p.concur_callee = callee
@@ -80,17 +73,12 @@ def verify_proxy(obj_or_type, exception = False, check_thread = True,
p.concur_tname = None
p.concur_callee = None
self.__obj = obj_or_type
try:
if type(obj_or_type) in (type, type):
p.classname = self.__obj.__name__
else:
p.classname = self.__obj.__class__.__name__
except AttributeError: # pragma: no cover
p.classname = "???"
if type(obj_or_type) in (type, type):
p.classname = self.__obj.__name__
else:
p.classname = self.__obj.__class__.__name__

def __getattr__(self, key):
if key.startswith("_VerifyObjectProxy__"): # pragma: no cover
raise AttributeError
attr = getattr(self.__obj, key)
if not callable(attr):
return VerifyCallProxy(getattr, self.__ns)(self.__obj, key)


+ 3
- 0
tests/test_serializer.py View File

@@ -29,6 +29,9 @@ class Foo(object):
def t(self):
pass

def reent(self, func):
func()

def tester(self, debug = False):
# purposely not thread-safe
self.test_thread = threading.current_thread().name


+ 8
- 8
tests/test_threadsafety.py View File

@@ -76,14 +76,14 @@ class TestThreadSafety(object):
def test(self):
proxy = nilmdb.utils.threadsafety.verify_proxy
self.tryit(Test(), True, True)
self.tryit(proxy(Test(), True, True, True), False, False)
self.tryit(proxy(Test(), True, True, False), False, True)
self.tryit(proxy(Test(), True, False, True), True, False)
self.tryit(proxy(Test(), True, False, False), True, True)
self.tryit(proxy(Test, True, True, True)(), False, False)
self.tryit(proxy(Test, True, True, False)(), False, True)
self.tryit(proxy(Test, True, False, True)(), True, False)
self.tryit(proxy(Test, True, False, False)(), True, True)
self.tryit(proxy(Test(), True, True), False, False)
self.tryit(proxy(Test(), True, False), False, True)
self.tryit(proxy(Test(), False, True), True, False)
self.tryit(proxy(Test(), False, False), True, True)
self.tryit(proxy(Test, True, True)(), False, False)
self.tryit(proxy(Test, True, False)(), False, True)
self.tryit(proxy(Test, False, True)(), True, False)
self.tryit(proxy(Test, False, False)(), True, True)

proxy(proxy(proxy(Test))()).foo()



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