def save_object(self, obj_type, obj_id, values={}):
"""
Save cache data for an object in the database.
"""
# If the ACL object exists
if len(ACLObjects.get_values(obj_type)) > 0:
try:
# If supplied, values argument must be a dictionary
if values and not isinstance(values, dict):
self.log.error('Failed to cache object <%s> of type <%s>, values keyword must contain a dictionary' % (obj_id, obj_type))
return False
# Get the ACL object definition
acl_object = ACLObjects.get(type=obj_type)
# Get an instance of the object class
obj_mod = importlib.import_module(getattr(acl_object, 'obj_mod'))
obj_class = getattr(obj_mod, getattr(acl_object, 'obj_cls'))
obj_key = getattr(acl_object, 'obj_key')
# Create the object filter
obj_filter = {}
obj_filter[obj_key] = obj_id
# Define the cache object filter
cache_filter = {
'object_type': obj_type,
'object_id': obj_id
}
# If the object doesn't exist anymore
if not obj_class.objects.filter(**obj_filter).count():
# If an expired cache entry exists
if DBClusterCache.objects.filter(**cache_filter).count():
self.log.info('Base object <%s> of type <%s> no longer exists, flushing cached entry' % (obj_id, obj_type))
# Flush the old cache entry
DBClusterCache.objects.filter(**cache_filter).delete()
# Expired cache object cleared
return True
# Get the object details
obj_details = base64.encodestring(json.dumps(list(obj_class.objects.filter(**obj_filter).values(**values))[0], cls=DjangoJSONEncoder))
obj_size = sys.getsizeof(obj_details)
obj_hash = hashlib.md5(obj_details).hexdigest()
# If the object already has a cache entry
if DBClusterCache.objects.filter(**cache_filter).count():
# Get the current cache entry
cache_row = list(DBClusterCache.objects.filter(**cache_filter).values())[0]
# If the cached data hasn't changed
if cache_row['object_hash'] == obj_hash:
return self.log.info('Cached data unchanged for object <%s> of type <%s>' % (obj_id, obj_type))
# Update the cached data
DBClusterCache.objects.filter(**cache_filter).update(object_data=obj_details, object_size=obj_size)
# Create a new cache entry
else:
# Create the cache entry
DBClusterCache(
object_type = acl_object,
object_id = obj_id,
object_data = obj_details,
object_hash = obj_hash,
object_size = obj_size
).save()
# Object successfull cached
self.log.info('Cached data for object <%s> of type <%s>: bytes_cached=%s, hash=%s' % (obj_id, obj_type, str(obj_size), obj_hash))
# Critical error when caching object
except Exception as e:
self.log.exception('Failed to cache object <%s> of type <%s>: %s' % (obj_id, obj_type, str(e)))
# ACL object does not exist
else:
self.log.error('Cannot cache object <%s> of type <%s>, ACL object type not found' % (obj_id, obj_type))
def _get_from_model(self, obj_type, obj_id, values={}, filters={}):
"""
Retrieve object details directly from the model.
@param obj_type: The type of object to retrieve
@type obj_type: str
@param obj_id: The ID of the object to retrieve
@type obj_id: str
@param values: Extra parameters to pass to the values QuerySet method
@type values: dict
@param filters: Extra filter parameters
@type filters: dict
"""
self.log.info('Retrieving object data from model: type=%s, id=%s' % (obj_type, repr(obj_id)))
# Get the ACL object definition
acl_object = ACLObjects.get(obj_type)
# Get an instance of the object class
obj_mod = importlib.import_module(getattr(acl_object, 'obj_mod'))
obj_class = getattr(obj_mod, getattr(acl_object, 'obj_cls'))
obj_key = getattr(acl_object, 'obj_key')
# Create the object filter
obj_filter = {}
# If retrieving a single object
if obj_id:
obj_filter[obj_key] = obj_id
# Create the query object
query_obj = obj_class.objects
# If an object filter is defined
if obj_filter:
self.log.info('Applying object filters: %s' % json.dumps(obj_filter))
query_obj = query_obj.filter(**obj_filter)
# If a values filter is defined
if filters:
self.log.info('Applying value filters: %s' % json.dumps(filters))
query_obj = query_obj.filter(**filters)
# If no filters were defined
if not obj_filter and not filters:
self.log.info('No filters defined, retrieving all objects')
query_obj = query_obj.all()
# Log the constructed query object
self.log.info('Constructed object query: %s' % str(query_obj))
# Attempt to retrieve the object
obj_details = list(query_obj.values())
# Log the retrieved details
log_data = json.dumps(obj_details, cls=DjangoJSONEncoder)
self.log.info('Retrieved object details: length=%s, data=%s' % (len(log_data), (log_data[:75] + '...') if len(log_data) > 75 else log_data))
# If the object doesn't exist
if len(obj_details) == 0:
return None
# Return the object details
if not obj_id:
return obj_details
return obj_details[0]
