def test_read_and_write_with_threads(self):
to_me = queue.Queue()
def get_read_lock():
with TableLock(read=[Alphabet]):
to_me.put("Reading")
try:
# Thread can obtain lock alone
other_thread = Thread(target=get_read_lock)
other_thread.start()
assert to_me.get() == "Reading"
with TableLock(write=[Alphabet]):
other_thread = Thread(target=get_read_lock)
other_thread.start()
# Doesn't lock now
with pytest.raises(queue.Empty):
to_me.get(timeout=0.2)
# Gets now
assert to_me.get() == "Reading"
finally:
other_thread.join()
def test_read_and_write(self):
Customer.objects.create(name="Fred")
with TableLock(read=[Customer], write=[Alphabet]):
assert self.is_locked("default", Alphabet._meta.db_table)
assert self.is_locked("default", Customer._meta.db_table)
ab = Alphabet.objects.create(a=Customer.objects.count())
assert ab.a == 1
def test_writes_fail_under_read(self):
with TableLock(read=[Alphabet]):
with pytest.raises(OperationalError) as excinfo:
Alphabet.objects.update(a=2)
assert "was locked with a READ lock and can't be updated" in str(
excinfo.value)
def test_creates_an_atomic(self):
assert connection.get_autocommit() == 1
assert not connection.in_atomic_block
with TableLock(read=[Alphabet]):
assert connection.get_autocommit() == 0
assert connection.in_atomic_block
assert connection.get_autocommit() == 1
assert not connection.in_atomic_block
def test_write(self):
Alphabet.objects.create(a=12345)
with TableLock(write=[Alphabet]):
assert Alphabet.objects.count() == 1
Alphabet.objects.all().delete()
assert Alphabet.objects.count() == 0
assert Alphabet.objects.count() == 0
def test_write_with_using(self):
Alphabet.objects.using('other').create(a=878787)
with TableLock(write=[Alphabet], using='other'):
assert Alphabet.objects.using('other').count() == 1
Alphabet.objects.using('other').all().delete()
assert Alphabet.objects.using('other').count() == 0
assert Alphabet.objects.using('other').count() == 0
def test_write_with_table_name(self):
Alphabet.objects.create(a=71718)
with TableLock(write=[Alphabet._meta.db_table]):
assert Alphabet.objects.count() == 1
Alphabet.objects.all().delete()
assert Alphabet.objects.count() == 0
assert Alphabet.objects.count() == 0
def test_write_with_using(self):
Alphabet.objects.using("other").create(a=878787)
assert not self.is_locked("other", Alphabet._meta.db_table)
with TableLock(write=[Alphabet], using="other"):
assert self.is_locked("other", Alphabet._meta.db_table)
assert Alphabet.objects.using("other").count() == 1
Alphabet.objects.using("other").all().delete()
assert Alphabet.objects.using("other").count() == 0
assert not self.is_locked("other", Alphabet._meta.db_table)
assert Alphabet.objects.using("other").count() == 0
def test_write(self):
Alphabet.objects.create(a=12345)
assert not self.is_locked("default", Alphabet._meta.db_table)
with TableLock(write=[Alphabet]):
assert self.is_locked("default", Alphabet._meta.db_table)
assert Alphabet.objects.count() == 1
Alphabet.objects.all().delete()
assert Alphabet.objects.count() == 0
assert not self.is_locked("default", Alphabet._meta.db_table)
assert Alphabet.objects.count() == 0
def test_inherited_model(self):
TitledAgedCustomer.objects.create(title="Sir", name="Knighty")
with TableLock(write=[TitledAgedCustomer]):
assert Customer.objects.count() == 1
TitledAgedCustomer.objects.create(name="Grandpa Potts", age=99)
assert Customer.objects.count() == 2
assert TitledAgedCustomer.objects.count() == 2
TitledAgedCustomer.objects.all().delete()
assert Customer.objects.count() == 0
assert AgedCustomer.objects.count() == 0
assert TitledAgedCustomer.objects.count() == 0
assert Customer.objects.count() == 0
assert AgedCustomer.objects.count() == 0
assert TitledAgedCustomer.objects.count() == 0
def get_read_lock():
with TableLock(read=[Alphabet]):
to_me.put("Reading")
def test_write_fails_touching_other_table(self):
with pytest.raises(OperationalError) as excinfo:
with TableLock(write=[Alphabet]):
Customer.objects.create(name="Lizzy")
assert excinfo.value.args[0] == 1100 # ER_TABLE_NOT_LOCKED
def test_write_with_table_name(self):
assert not self.is_locked("default", Alphabet._meta.db_table)
with TableLock(write=[Alphabet._meta.db_table]):
assert self.is_locked("default", Alphabet._meta.db_table)
def test_acquire_release(self):
my_lock = TableLock(read=[Alphabet])
my_lock.acquire()
my_lock.release()
def test_read_and_write(self):
Customer.objects.create(name="Fred")
with TableLock(read=[Customer], write=[Alphabet]):
ab = Alphabet.objects.create(a=Customer.objects.count())
assert ab.a == 1
def test_write_fails_touching_other_table(self):
with pytest.raises(OperationalError) as excinfo:
with TableLock(write=[Alphabet]):
Customer.objects.create(name="Lizzy")
assert "was not locked with LOCK TABLES" in str(excinfo.value)
def test_write_twice(self):
with TableLock(write=[Alphabet]):
Alphabet.objects.create(a=1)
with TableLock(write=[Alphabet]):
Alphabet.objects.create(a=2)
def test_fails_in_atomic(self):
with atomic(), pytest.raises(TransactionManagementError) as excinfo:
with TableLock(read=[Alphabet]):
pass
assert str(excinfo.value).startswith("InnoDB requires that we not be")
def test_acquire_release(self):
my_lock = TableLock(read=[Alphabet])
my_lock.acquire()
my_lock.release()