For now, the database is in memory.
We use dict data structures (KV) with the expectation of having to move this into Redis
"""
-from a1.exceptions import PolicyTypeNotFound, PolicyInstanceNotFound, PolicyTypeAlreadyExists
+import os
+import time
+from threading import Thread
+import msgpack
+from a1.exceptions import PolicyTypeNotFound, PolicyInstanceNotFound, PolicyTypeAlreadyExists, CantDeleteNonEmptyType
from a1 import get_module_logger
logger = get_module_logger(__name__)
-# This is essentially mockouts for future KV
-# Note that the D subkey won't be needed when in redis, since you can store data at x anx x_y
-POLICY_DATA = {}
-I = "instances"
-H = "handlers"
-D = "data"
-# Types
+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:
+ """
+ This is a wrapper around the expected SDL Python interface.
+ The usage of POLICY_DATA will be replaced with SDL when SDL for python is available.
+ The eventual SDL API is expected to be very close to what is here.
+
+ We use msgpack for binary (de)serialization: https://msgpack.org/index.html
+ """
+
+ def __init__(self):
+ self.POLICY_DATA = {}
+
+ def set(self, key, value):
+ """set a key"""
+ self.POLICY_DATA[key] = msgpack.packb(value, use_bin_type=True)
+
+ def get(self, key):
+ """get a key"""
+ if key in self.POLICY_DATA:
+ return msgpack.unpackb(self.POLICY_DATA[key], raw=False)
+ return None
+
+ def find_and_get(self, prefix):
+ """get all k v pairs that start with prefix"""
+ return {k: msgpack.unpackb(v, raw=False) for k, v in self.POLICY_DATA.items() if k.startswith(prefix)}
+
+ def delete(self, key):
+ """ delete a key"""
+ del self.POLICY_DATA[key]
+
+
+SDL = SDLWrapper()
+
+TYPE_PREFIX = "a1.policy_type."
+INSTANCE_PREFIX = "a1.policy_instance."
+METADATA_PREFIX = "a1.policy_inst_metadata."
+HANDLER_PREFIX = "a1.policy_handler."
+
+
+# Internal helpers
+
+
+def _generate_type_key(policy_type_id):
+ """
+ generate a key for a policy type
+ """
+ return "{0}{1}".format(TYPE_PREFIX, policy_type_id)
+
+
+def _generate_instance_key(policy_type_id, policy_instance_id):
+ """
+ generate a key for a policy instance
+ """
+ return "{0}{1}.{2}".format(INSTANCE_PREFIX, policy_type_id, policy_instance_id)
-def type_is_valid(policy_type_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}.{2}.".format(HANDLER_PREFIX, policy_type_id, policy_instance_id)
+
+
+def _generate_handler_key(policy_type_id, policy_instance_id, handler_id):
+ """
+ generate a key for a policy handler
+ """
+ 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 policy_type_id not in POLICY_DATA:
- logger.error("%s not found", policy_type_id)
+ if SDL.get(_generate_type_key(policy_type_id)) is None:
raise PolicyTypeNotFound()
-def store_policy_type(policy_type_id, body):
+def _instance_is_valid(policy_type_id, policy_instance_id):
"""
- store a policy type if it doesn't already exist
+ check that an instance is valid
"""
- if policy_type_id in POLICY_DATA:
- raise PolicyTypeAlreadyExists()
+ _type_is_valid(policy_type_id)
+ if SDL.get(_generate_instance_key(policy_type_id, policy_instance_id)) is None:
+ raise PolicyInstanceNotFound
- POLICY_DATA[policy_type_id] = {}
- POLICY_DATA[policy_type_id][D] = body
- POLICY_DATA[policy_type_id][I] = {}
+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)
+ 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())
-def get_policy_type(policy_type_id):
+
+def _get_instance_list(policy_type_id):
"""
- retrieve a type
+ shared helper to get instance list for a type
"""
- type_is_valid(policy_type_id)
- return POLICY_DATA[policy_type_id][D]
+ _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]
+
+
+def _clear_handlers(policy_type_id, policy_instance_id):
+ """
+ delete all the handlers for a policy instance
+ """
+ all_handlers_pref = _generate_handler_prefix(policy_type_id, policy_instance_id)
+ keys = SDL.find_and_get(all_handlers_pref)
+ for k in keys:
+ SDL.delete(k)
+
+
+def _get_metadata(policy_type_id, policy_instance_id):
+ """
+ get instance metadata
+ """
+ _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)
+
+
+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)
+
+ time.sleep(ttl)
+
+ # 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
+ logger.debug("type %s instance %s deleted", policy_type_id, policy_instance_id)
+ raise PolicyInstanceNotFound()
+
+
+# Types
def get_type_list():
"""
retrieve all type ids
"""
- return list(POLICY_DATA.keys())
+ typekeys = SDL.find_and_get(TYPE_PREFIX).keys()
+ # policy types are ints but they get butchered to strings in the KV
+ return [int(k.split(TYPE_PREFIX)[1]) for k in typekeys]
-# Instances
+def store_policy_type(policy_type_id, body):
+ """
+ store a policy type if it doesn't already exist
+ """
+ key = _generate_type_key(policy_type_id)
+ if SDL.get(key) is not None:
+ raise PolicyTypeAlreadyExists()
+ SDL.set(key, body)
-def instance_is_valid(policy_type_id, policy_instance_id):
+def delete_policy_type(policy_type_id):
"""
- check that an instance is valid
+ delete a policy type; can only be done if there are no instances (business logic)
"""
- type_is_valid(policy_type_id)
- if policy_instance_id not in POLICY_DATA[policy_type_id][I]:
- raise PolicyInstanceNotFound
+ pil = get_instance_list(policy_type_id)
+ if pil == []: # empty, can delete
+ SDL.delete(_generate_type_key(policy_type_id))
+ else:
+ raise CantDeleteNonEmptyType()
+
+
+def get_policy_type(policy_type_id):
+ """
+ retrieve a type
+ """
+ _type_is_valid(policy_type_id)
+ return SDL.get(_generate_type_key(policy_type_id))
+
+
+# Instances
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
- # Reset the statuses because this is a new policy instance, even if it was overwritten
- POLICY_DATA[policy_type_id][I][policy_instance_id] = {}
- POLICY_DATA[policy_type_id][I][policy_instance_id][D] = instance
- POLICY_DATA[policy_type_id][I][policy_instance_id][H] = {}
+ 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
"""
- type_is_valid(policy_type_id)
- instance_is_valid(policy_type_id, policy_instance_id)
- return POLICY_DATA[policy_type_id][I][policy_instance_id][D]
+ _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
+ """
+ return _get_instance_list(policy_type_id)
+
+
+def delete_policy_instance(policy_type_id, policy_instance_id):
+ """
+ initially sets has_been_deleted
+ then launches a thread that waits until the relevent timer expires, and finally deletes the instance
"""
- type_is_valid(policy_type_id)
- instance_is_valid(policy_type_id, policy_instance_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},
+ )
- return [{"handler_id": k, "status": v} for k, v in POLICY_DATA[policy_type_id][I][policy_instance_id][H].items()]
+ # 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_policy_instance_status(policy_type_id, policy_instance_id, handler_id, status):
"""
- Update the status of a handler id of a policy instance
+ 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)
-
- POLICY_DATA[policy_type_id][I][policy_instance_id][H][handler_id] = status
+ _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_instance_list(policy_type_id):
+def get_policy_instance_status(policy_type_id, policy_instance_id):
"""
- retrieve all instance ids for a type
+ Gets the status of an instance
"""
- type_is_valid(policy_type_id)
- return list(POLICY_DATA[policy_type_id][I].keys())
+ _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