def test_readwrite(self):
self.assertFalse(was_db_written())
set_thread_readwrite_db()
master = 'my_master_db'
with override_settings(MASTER_DATABASE=master):
router = DBRouter()
out = router.db_for_read(Submission)
self.assertEqual(master, out)
out = router.db_for_write(Submission)
self.assertEqual(master, out)
self.assertTrue(was_db_written())
def test_readonly_one_replica(self):
set_thread_readonly_db()
replica = 'my-only-replica-db'
pool = {
replica: 1
}
with override_settings(DATABASE_POOL=pool):
router = DBRouter()
out = router.db_for_read(Submission)
self.assertEqual(replica, out)
out = router.db_for_read(Submission)
self.assertEqual(replica, out)
self.assertFalse(was_db_written())
def test_writing_sets_db_written_flag(self):
router = DBRouter()
router.db_for_read(Submission)
self.assertFalse(was_db_written())
router.db_for_write(Submission)
self.assertTrue(was_db_written())
# A read won't reset the flag
router.db_for_read(Submission)
self.assertTrue(was_db_written())
def test_readonly_three_replicas(self):
set_thread_readonly_db()
replica0 = 'my-replica-db0'
replica1 = 'my-replica-db1'
replica2 = 'my-replica-db2'
pool = {
replica0: 1,
replica1: 1,
replica2: 1,
}
replicas = pool.keys()
with override_settings(DATABASE_POOL=pool):
router = DBRouter()
out0 = router.db_for_read(Submission)
self.assertIn(out0, replicas)
out1 = router.db_for_read(Submission)
self.assertIn(out1, replicas)
self.assertNotEqual(out0, out1)
out2 = router.db_for_read(Submission)
self.assertIn(out2, replicas)
self.assertNotEqual(out1, out2)
out3 = router.db_for_read(Submission)
# Round-robin should have come around by now
self.assertEqual(out3, out0)
self.assertFalse(was_db_written())
def test_middleware_validation(self):
# The router raises an error if the necessary middleware is not configured.
with override_settings(MIDDLEWARE_CLASSES=[]):
with self.assertRaises(ImproperlyConfigured):
DBRouter()
