+"""
+Represents A1s database and database access functions.
+In the future, this may change to use a different backend, possibly dramatically.
+Hopefully, the access functions are a good api so nothing else has to change when this happens
+
+For now, the database is in memory.
+We use dict data structures (KV) with the expectation of having to move this into Redis
+"""
# ==================================================================================
# Copyright (c) 2019 Nokia
# Copyright (c) 2018-2019 AT&T Intellectual Property.
# See the License for the specific language governing permissions and
# limitations under the License.
# ==================================================================================
-
-"""
-Represents A1s database and database access functions.
-In the future, this may change to use a different backend, possibly dramatically.
-Hopefully, the access functions are a good api so nothing else has to change when this happens
-
-For now, the database is in memory.
-We use dict data structures (KV) with the expectation of having to move this into Redis
-"""
+import os
+import time
+from threading import Thread
import msgpack
+from mdclogpy import Logger
from a1.exceptions import PolicyTypeNotFound, PolicyInstanceNotFound, PolicyTypeAlreadyExists, CantDeleteNonEmptyType
-from a1 import get_module_logger
-logger = get_module_logger(__name__)
+mdc_logger = Logger(name=__name__)
+
+
+INSTANCE_DELETE_NO_RESP_TTL = int(os.environ.get("INSTANCE_DELETE_NO_RESP_TTL", 5))
+INSTANCE_DELETE_RESP_TTL = int(os.environ.get("INSTANCE_DELETE_RESP_TTL", 5))
class SDLWrapper:
TYPE_PREFIX = "a1.policy_type."
INSTANCE_PREFIX = "a1.policy_instance."
+METADATA_PREFIX = "a1.policy_inst_metadata."
HANDLER_PREFIX = "a1.policy_handler."
return "{0}{1}.{2}".format(INSTANCE_PREFIX, policy_type_id, policy_instance_id)
+def _generate_instance_metadata_key(policy_type_id, policy_instance_id):
+ """
+ generate a key for a policy instance metadata
+ """
+ return "{0}{1}.{2}".format(METADATA_PREFIX, policy_type_id, policy_instance_id)
+
+
def _generate_handler_prefix(policy_type_id, policy_instance_id):
"""
generate the prefix to a handler key
return "{0}{1}".format(_generate_handler_prefix(policy_type_id, policy_instance_id), handler_id)
+def _type_is_valid(policy_type_id):
+ """
+ check that a type is valid
+ """
+ if SDL.get(_generate_type_key(policy_type_id)) is None:
+ raise PolicyTypeNotFound()
+
+
+def _instance_is_valid(policy_type_id, policy_instance_id):
+ """
+ check that an instance is valid
+ """
+ _type_is_valid(policy_type_id)
+ if SDL.get(_generate_instance_key(policy_type_id, policy_instance_id)) is None:
+ raise PolicyInstanceNotFound
+
+
def _get_statuses(policy_type_id, policy_instance_id):
"""
shared helper to get statuses for an instance
"""
- instance_is_valid(policy_type_id, policy_instance_id)
+ _instance_is_valid(policy_type_id, policy_instance_id)
prefixes_for_handler = "{0}{1}.{2}.".format(HANDLER_PREFIX, policy_type_id, policy_instance_id)
return list(SDL.find_and_get(prefixes_for_handler).values())
"""
shared helper to get instance list for a type
"""
- type_is_valid(policy_type_id)
+ _type_is_valid(policy_type_id)
prefixes_for_type = "{0}{1}.".format(INSTANCE_PREFIX, policy_type_id)
instancekeys = SDL.find_and_get(prefixes_for_type).keys()
return [k.split(prefixes_for_type)[1] for k in instancekeys]
SDL.delete(k)
-def _clean_up_type(policy_type_id):
+def _get_metadata(policy_type_id, policy_instance_id):
"""
- for all instances of type, see if it can be deleted
+ get instance metadata
"""
- type_is_valid(policy_type_id)
- for policy_instance_id in _get_instance_list(policy_type_id):
- # see if we can delete
- vector = _get_statuses(policy_type_id, policy_instance_id)
+ _instance_is_valid(policy_type_id, policy_instance_id)
+ metadata_key = _generate_instance_metadata_key(policy_type_id, policy_instance_id)
+ return SDL.get(metadata_key)
- """
- TODO: not being able to delete if the list is [] is prolematic.
- There are cases, such as a bad routing file, where this type will never be able to be deleted because it never went to any xapps
- However, A1 cannot distinguish between the case where [] was never going to work, and the case where it hasn't worked *yet*
- However, removing this constraint also leads to problems.
- Deleting the instance when the vector is empty, for example doing so “shortly after” the PUT, can lead to a worse race condition where the xapps get the policy after that, implement it, but because the DELETE triggered “too soon”, you can never get the status or do the delete on it again, so the xapps are all implementing the instance roguely.
+def _delete_after(policy_type_id, policy_instance_id, ttl):
+ """
+ this is a blocking function, must call this in a thread to not block!
+ waits ttl seconds, then deletes the instance
+ """
+ _instance_is_valid(policy_type_id, policy_instance_id)
- This requires some thought to address.
- For now we stick with the "less bad problem".
- """
- if vector != []:
- all_deleted = True
- for i in vector:
- if i != "DELETED":
- all_deleted = False
- break # have at least one not DELETED, do nothing
+ time.sleep(ttl)
- # blow away from a1 db
- if all_deleted:
- _clear_handlers(policy_type_id, policy_instance_id) # delete all the handlers
- SDL.delete(_generate_instance_key(policy_type_id, policy_instance_id)) # delete instance
+ # ready to delete
+ _clear_handlers(policy_type_id, policy_instance_id) # delete all the handlers
+ SDL.delete(_generate_instance_key(policy_type_id, policy_instance_id)) # delete instance
+ SDL.delete(_generate_instance_metadata_key(policy_type_id, policy_instance_id)) # delete instance metadata
+ mdc_logger.debug("type {0} instance {1} deleted".format(policy_type_id, policy_instance_id))
# Types
return [int(k.split(TYPE_PREFIX)[1]) for k in typekeys]
-def type_is_valid(policy_type_id):
- """
- check that a type is valid
- """
- if SDL.get(_generate_type_key(policy_type_id)) is None:
- raise PolicyTypeNotFound()
-
-
def store_policy_type(policy_type_id, body):
"""
store a policy type if it doesn't already exist
"""
retrieve a type
"""
- type_is_valid(policy_type_id)
+ _type_is_valid(policy_type_id)
return SDL.get(_generate_type_key(policy_type_id))
# Instances
-def instance_is_valid(policy_type_id, policy_instance_id):
- """
- check that an instance is valid
- """
- type_is_valid(policy_type_id)
- if SDL.get(_generate_instance_key(policy_type_id, policy_instance_id)) is None:
- raise PolicyInstanceNotFound
-
-
def store_policy_instance(policy_type_id, policy_instance_id, instance):
"""
Store a policy instance
"""
- type_is_valid(policy_type_id)
+ _type_is_valid(policy_type_id)
+ creation_timestamp = time.time()
+
+ # store the instance
key = _generate_instance_key(policy_type_id, policy_instance_id)
if SDL.get(key) is not None:
# Reset the statuses because this is a new policy instance, even if it was overwritten
_clear_handlers(policy_type_id, policy_instance_id) # delete all the handlers
SDL.set(key, instance)
+ metadata_key = _generate_instance_metadata_key(policy_type_id, policy_instance_id)
+ SDL.set(metadata_key, {"created_at": creation_timestamp, "has_been_deleted": False})
+
def get_policy_instance(policy_type_id, policy_instance_id):
"""
Retrieve a policy instance
"""
- _clean_up_type(policy_type_id)
- instance_is_valid(policy_type_id, policy_instance_id)
+ _instance_is_valid(policy_type_id, policy_instance_id)
return SDL.get(_generate_instance_key(policy_type_id, policy_instance_id))
-def get_policy_instance_statuses(policy_type_id, policy_instance_id):
+def get_instance_list(policy_type_id):
"""
- Retrieve the status vector for a policy instance
+ retrieve all instance ids for a type
"""
- _clean_up_type(policy_type_id)
- return _get_statuses(policy_type_id, policy_instance_id)
+ return _get_instance_list(policy_type_id)
-def get_instance_list(policy_type_id):
+def delete_policy_instance(policy_type_id, policy_instance_id):
"""
- retrieve all instance ids for a type
+ initially sets has_been_deleted
+ then launches a thread that waits until the relevent timer expires, and finally deletes the instance
"""
- _clean_up_type(policy_type_id)
- return _get_instance_list(policy_type_id)
+ _instance_is_valid(policy_type_id, policy_instance_id)
+
+ # set the metadata first
+ deleted_timestamp = time.time()
+ metadata_key = _generate_instance_metadata_key(policy_type_id, policy_instance_id)
+ existing_metadata = _get_metadata(policy_type_id, policy_instance_id)
+ SDL.set(
+ metadata_key,
+ {"created_at": existing_metadata["created_at"], "has_been_deleted": True, "deleted_at": deleted_timestamp},
+ )
+
+ # wait, then delete
+ vector = _get_statuses(policy_type_id, policy_instance_id)
+ if vector == []:
+ # handler is empty; we wait for t1 to expire then goodnight
+ clos = lambda: _delete_after(policy_type_id, policy_instance_id, INSTANCE_DELETE_NO_RESP_TTL)
+ else:
+ # handler is not empty, we wait max t1,t2 to expire then goodnight
+ clos = lambda: _delete_after(
+ policy_type_id, policy_instance_id, max(INSTANCE_DELETE_RESP_TTL, INSTANCE_DELETE_NO_RESP_TTL)
+ )
+ Thread(target=clos).start()
# Statuses
-def set_status(policy_type_id, policy_instance_id, handler_id, status):
+def set_policy_instance_status(policy_type_id, policy_instance_id, handler_id, status):
"""
update the database status for a handler
called from a1's rmr thread
"""
- type_is_valid(policy_type_id)
- instance_is_valid(policy_type_id, policy_instance_id)
+ _type_is_valid(policy_type_id)
+ _instance_is_valid(policy_type_id, policy_instance_id)
SDL.set(_generate_handler_key(policy_type_id, policy_instance_id, handler_id), status)
+
+
+def get_policy_instance_status(policy_type_id, policy_instance_id):
+ """
+ Gets the status of an instance
+ """
+ _instance_is_valid(policy_type_id, policy_instance_id)
+ metadata = _get_metadata(policy_type_id, policy_instance_id)
+ metadata["instance_status"] = "NOT IN EFFECT"
+ for i in _get_statuses(policy_type_id, policy_instance_id):
+ if i == "OK":
+ metadata["instance_status"] = "IN EFFECT"
+ break
+ return metadata
Code Review / ric-plt / a1.git / blobdiff