def source_model_post_save(sender, instance, created, **kwargs):
# for clarity
source_model = sender
source_instance = instance
affected_targets = source_instance._denorm_affected_targets
if not affected_targets:
# nothing to denorm
return
#
# create a task for each affected target to update its instances
#
for target_model, affected_target in affected_targets.iteritems():
# if storage is shared_dict, then task will pluralize related_field_name to get target model's list field
related_field_name = affected_target['related']
strategy = affected_target['strategy']
storage = affected_target['storage']
shards = affected_target['shards']
affected_fields = affected_target['fields']
#logging.info('affected target %s.%s for source %s: %s' % (target_model, related_field_name, source_model, affected_fields))
# for each affected target, create a separate task
instance_id = source_instance.id
tag = 'DENORM_SOURCE_%s_%s_TARGET_%s' % (util.get_model_name(
source_model), instance_id, util.get_model_name(target_model))
payload = {
'created': timezone.now().isoformat(),
'strategy': strategy,
'storage': storage,
'instance_id': instance_id,
'source_model': util.get_model_name(source_model),
'target_model': util.get_model_name(target_model),
'related_field': related_field_name,
'fields': affected_fields,
# TODO: queue name should be configurable
'queue_name': 'denorm'
}
if strategy == 'mapreduce':
payload['shards'] = handler_for_name(shards)(
source_instance) if shards else DEFAULT_MAP_REDUCE_SHARDS
payload_string = util.dump_json(payload)
logging.info(
'[denorm source_model_post_save] queue task payload = %s' %
payload_string)
# create a pull task per target
taskqueue.Queue('pull-denorm').add(
taskqueue.Task(payload=payload_string, tag=tag, method='PULL'))
# create ** one ** Task model instance used to track denorm tasks per source, particularly for throttling
models.get_task_model().objects.create(
source_model=util.get_model_name(source_model),
source_instance_id=source_instance.id,
user=source_instance._denorm_user,
label=source_instance._denorm_label)
# re-run post_init to reset _denorm_orig_values in case this instance gets saved again
source_model_post_init(source_model, source_instance)
def source_model_post_save(sender, instance, created, **kwargs):
# for clarity
source_model = sender
source_instance = instance
affected_targets = source_instance._denorm_affected_targets
if not affected_targets:
# nothing to denorm
return
#
# create a task for each affected target to update its instances
#
for target_model, affected_target in affected_targets.iteritems():
# if storage is shared_dict, then task will pluralize related_field_name to get target model's list field
related_field_name = affected_target['related']
strategy = affected_target['strategy']
storage = affected_target['storage']
shards = affected_target['shards']
affected_fields = affected_target['fields']
#logging.info('affected target %s.%s for source %s: %s' % (target_model, related_field_name, source_model, affected_fields))
# for each affected target, create a separate task
instance_id = source_instance.id
tag = 'DENORM_SOURCE_%s_%s_TARGET_%s' % (util.get_model_name(source_model), instance_id, util.get_model_name(target_model))
payload = {
'created': timezone.now().isoformat(),
'strategy': strategy,
'storage': storage,
'instance_id': instance_id,
'source_model': util.get_model_name(source_model),
'target_model': util.get_model_name(target_model),
'related_field': related_field_name,
'fields': affected_fields,
# TODO: queue name should be configurable
'queue_name': 'denorm'
}
if strategy == 'mapreduce':
payload['shards'] = handler_for_name(shards)(source_instance) if shards else DEFAULT_MAP_REDUCE_SHARDS
payload_string = util.dump_json(payload)
logging.info('[denorm source_model_post_save] queue task payload = %s' % payload_string)
# create a pull task per target
taskqueue.Queue('pull-denorm').add(
taskqueue.Task(payload=payload_string, tag=tag, method='PULL')
)
# create ** one ** Task model instance used to track denorm tasks per source, particularly for throttling
models.get_task_model().objects.create(
source_model=util.get_model_name(source_model),
source_instance_id=source_instance.id,
user=source_instance._denorm_user,
label=source_instance._denorm_label
)
# re-run post_init to reset _denorm_orig_values in case this instance gets saved again
source_model_post_init(source_model, source_instance)
def source_model_pre_save(sender, instance, raw, using, update_fields,
**kwargs):
# for clarity
source_model = sender
source_instance = instance
created = not source_instance.id
source_instance._denorm_affected_targets = affected_targets = {}
# newly created instances will not need denormalization
if created:
return
# denorm turned off
if not getattr(source_instance, '_denorm', True):
return
source_graph = core.SOURCE_GRAPH[source_model]
#
# iterate through all fields to build up set of distinct affected targets that post_save signal receiver will process.
#
source_graph_fields = source_graph['fields']
orig_values = source_instance._denorm_orig_values
for source_field, targets in source_graph_fields.iteritems():
old_value = orig_values[source_field]
new_value = getattr(source_instance, source_field)
if old_value != new_value:
#logging.info('[%s] %s value changed from "%s" to "%s"' % (source_model, source_field, old_value, new_value))
for target in targets:
target_model = target['target_model']
related_field_name = target['source']
storage = target['storage']
affected_targets[
target_model] = affected_target = affected_targets.get(
target_model, {
'related': related_field_name,
'strategy': target['strategy'],
'storage': storage,
'shards': target['shards'],
'fields': {}
})
# when task will update target, if storage is scalar, then field name is simply target model field name.
# and if storage is shared_dict, then the field name is the dictionary key of the target model's denorm_data field.
affected_fields_for_target = affected_target['fields']
affected_fields_for_target['%s_%s' %
(related_field_name,
source_field)] = new_value
if not affected_targets:
return
#
# check that denorm throttling threshold is not exceeded
#
# get user from thread-local variable set by middleware
user = middleware.get_current_user()
if not user or not isinstance(user, get_user_model(
)) or not user.is_authenticated() or user.is_superuser:
user = None
source_instance._denorm_user = user
# get denorm label used for throttling
if 'label' in source_graph:
# custom label set by application
label = source_graph['label'](source_instance, user)
else:
# default label
if user:
label = '%s_%s' % (util.get_model_name(source_model), str(user.id))
else:
# no label
label = None
source_instance._denorm_label = label
throttles = source_graph.get('throttles')
if not label or not throttles:
# no throttling
return
# now validate each throttle
# FIXME: we need to figure out if there is already a denorm task scheduled, and if so, then don't penalize throttle.
# FIXME: perhaps we can use a Task.status field in combination with filter for source instance id.
now = timezone.now()
for throttle in throttles:
num_requests, duration = util.parse_rate(throttle)
# FIXME: this is a naive, inefficient implementation. we should cache task counts.
if models.get_task_model().objects.filter(
label=label, created__gt=now -
timedelta(seconds=duration)).count() >= num_requests:
raise exceptions.DenormThrottled
def source_model_pre_save(sender, instance, raw, using, update_fields, **kwargs):
# for clarity
source_model = sender
source_instance = instance
created = not source_instance.id
source_instance._denorm_affected_targets = affected_targets = {}
# newly created instances will not need denormalization
if created:
return
# denorm turned off
if not getattr(source_instance, '_denorm', True):
return
source_graph = core.SOURCE_GRAPH[source_model]
#
# iterate through all fields to build up set of distinct affected targets that post_save signal receiver will process.
#
source_graph_fields = source_graph['fields']
orig_values = source_instance._denorm_orig_values
for source_field, targets in source_graph_fields.iteritems():
old_value = orig_values[source_field]
new_value = getattr(source_instance, source_field)
if old_value != new_value:
#logging.info('[%s] %s value changed from "%s" to "%s"' % (source_model, source_field, old_value, new_value))
for target in targets:
target_model = target['target_model']
related_field_name = target['source']
storage = target['storage']
affected_targets[target_model] = affected_target = affected_targets.get(target_model, {
'related': related_field_name,
'strategy': target['strategy'],
'storage': storage,
'shards': target['shards'],
'fields': {}
})
# when task will update target, if storage is scalar, then field name is simply target model field name.
# and if storage is shared_dict, then the field name is the dictionary key of the target model's denorm_data field.
affected_fields_for_target = affected_target['fields']
affected_fields_for_target['%s_%s' % (related_field_name, source_field)] = new_value
if not affected_targets:
return
#
# check that denorm throttling threshold is not exceeded
#
# get user from thread-local variable set by middleware
user = middleware.get_current_user()
if not user or not isinstance(user, get_user_model()) or not user.is_authenticated() or user.is_superuser:
user = None
source_instance._denorm_user = user
# get denorm label used for throttling
if 'label' in source_graph:
# custom label set by application
label = source_graph['label'](source_instance, user)
else:
# default label
if user:
label = '%s_%s' % (util.get_model_name(source_model), str(user.id))
else:
# no label
label = None
source_instance._denorm_label = label
throttles = source_graph.get('throttles')
if not label or not throttles:
# no throttling
return
# now validate each throttle
# FIXME: we need to figure out if there is already a denorm task scheduled, and if so, then don't penalize throttle.
# FIXME: perhaps we can use a Task.status field in combination with filter for source instance id.
now = timezone.now()
for throttle in throttles:
num_requests, duration = util.parse_rate(throttle)
# FIXME: this is a naive, inefficient implementation. we should cache task counts.
if models.get_task_model().objects.filter(label=label, created__gt=now - timedelta(seconds=duration)).count() >= num_requests:
raise exceptions.DenormThrottled
