def test_run_operation_creates_and_updates_task_marker(self):
""" If we run one of our custom operations, then it should create the task marker in the DB
and defer a task, then set the marker to 'is_finished' when done.
"""
TestModel.objects.create()
operation = operations.AddFieldData(
"testmodel", "new_field",
models.CharField(max_length=100, default="squirrel"))
self.start_operation(operation)
# Now check that the task marker has been created.
# Usefully, calling database_forwards() on the operation will have caused it to set the
# `identifier` attribute on itself, meaning we can now just call _get_task_marker()
task_marker = datastore.Get([
ShardedTaskMarker.get_key(operation.identifier,
operation.namespace)
])[0]
if task_marker is None:
self.fail("Migration operation did not create its task marker")
self.assertFalse(task_marker.get("is_finished"))
self.assertNumTasksEquals(1)
self.process_task_queues()
# Now check that the task marker has been marked as finished
task_marker = datastore.Get([
ShardedTaskMarker.get_key(operation.identifier,
operation.namespace)
])[0]
self.assertTrue(task_marker["is_finished"])
self.assertNumTasksEquals(0)
def test_running_finished_operation_does_not_trigger_new_task(self):
""" If we re-trigger an operation which has already been run and finished, it should simply
return without starting a new task or updating the task marker.
"""
TestModel.objects.create()
operation = operations.AddFieldData(
"testmodel", "new_field", models.CharField(max_length=100, default="squirrel")
)
# Run the operation and check that it finishes
with sleuth.watch("djangae.db.migrations.operations.AddFieldData._start_task") as start:
self.start_operation(operation)
self.assertTrue(start.called)
task_marker = datastore.Get(
ShardedTaskMarker.get_key(operation.identifier, operation.namespace)
)
self.assertFalse(task_marker["is_finished"])
self.assertNumTasksEquals(1)
self.process_task_queues()
task_marker = datastore.Get(
ShardedTaskMarker.get_key(operation.identifier, operation.namespace)
)
self.assertTrue(task_marker["is_finished"])
# Run the operation again. It should see that's it's finished and just return immediately.
self.assertNumTasksEquals(0)
with sleuth.watch("djangae.db.migrations.operations.AddFieldData._start_task") as start:
self.start_operation(operation, detonate=False)
self.assertFalse(start.called)
self.assertNumTasksEquals(0)
task_marker = datastore.Get(
ShardedTaskMarker.get_key(operation.identifier, operation.namespace)
)
self.assertTrue(task_marker["is_finished"])
def test_running_finished_operation_does_not_trigger_new_task(self):
""" If we re-trigger an operation which has already been run and finished, it should simply
return without starting a new task or updating the task marker.
"""
TestModel.objects.create()
operation = operations.AddFieldData(
"testmodel", "new_field", models.CharField(max_length=100, default="squirrel")
)
# Run the operation and check that it finishes
with sleuth.watch("djangae.db.migrations.operations.AddFieldData._start_task") as start:
self.start_operation(operation)
self.assertTrue(start.called)
task_marker = datastore.Get(
ShardedTaskMarker.get_key(operation.identifier, operation.namespace)
)
self.assertFalse(task_marker["is_finished"])
self.assertNumTasksEquals(1)
self.process_task_queues()
task_marker = datastore.Get(
ShardedTaskMarker.get_key(operation.identifier, operation.namespace)
)
self.assertTrue(task_marker["is_finished"])
# Run the operation again. It should see that's it's finished and just return immediately.
self.assertNumTasksEquals(0)
with sleuth.watch("djangae.db.migrations.operations.AddFieldData._start_task") as start:
self.start_operation(operation, detonate=False)
self.assertFalse(start.called)
self.assertNumTasksEquals(0)
task_marker = datastore.Get(
ShardedTaskMarker.get_key(operation.identifier, operation.namespace)
)
self.assertTrue(task_marker["is_finished"])
def test_run_operation_creates_and_updates_task_marker(self):
""" If we run one of our custom operations, then it should create the task marker in the DB
and defer a task, then set the marker to 'is_finished' when done.
"""
TestModel.objects.create()
operation = operations.AddFieldData(
"testmodel", "new_field", models.CharField(max_length=100, default="squirrel")
)
self.start_operation(operation)
# Now check that the task marker has been created.
# Usefully, calling database_forwards() on the operation will have caused it to set the
# `identifier` attribute on itself, meaning we can now just call _get_task_marker()
task_marker = datastore.Get(
[ShardedTaskMarker.get_key(operation.identifier, operation.namespace)]
)[0]
if task_marker is None:
self.fail("Migration operation did not create its task marker")
self.assertFalse(task_marker.get("is_finished"))
self.assertNumTasksEquals(1)
self.process_task_queues()
# Now check that the task marker has been marked as finished
task_marker = datastore.Get(
[ShardedTaskMarker.get_key(operation.identifier, operation.namespace)]
)[0]
self.assertTrue(task_marker["is_finished"])
self.assertNumTasksEquals(0)
def test_starting_operation_twice_does_not_trigger_task_twice(self):
""" If we run an operation, and then try to run it again before the task has finished
processing, then it should not trigger a second task.
"""
TestModel.objects.create()
operation = operations.AddFieldData(
"testmodel", "new_field",
models.CharField(max_length=100, default="squirrel"))
self.start_operation(operation)
task_marker = datastore.Get(
ShardedTaskMarker.get_key(operation.identifier,
operation.namespace))
self.assertFalse(task_marker["is_finished"])
# We expect there to be a task queued for processing the operation
self.assertNumTasksEquals(1)
# Now try to run it again
self.start_operation(operation)
# We expect there to still be the same number of tasks
self.assertNumTasksEquals(1)
def test_starting_operation_twice_does_not_trigger_task_twice(self):
""" If we run an operation, and then try to run it again before the task has finished
processing, then it should not trigger a second task.
"""
TestModel.objects.create()
operation = operations.AddFieldData(
"testmodel", "new_field", models.CharField(max_length=100, default="squirrel")
)
self.start_operation(operation)
task_marker = datastore.Get(
ShardedTaskMarker.get_key(operation.identifier, operation.namespace)
)
self.assertFalse(task_marker["is_finished"])
# We expect there to be a task queued for processing the operation
self.assertNumTasksEquals(1)
# Now try to run it again
self.start_operation(operation)
# We expect there to still be the same number of tasks
self.assertNumTasksEquals(1)