nginx-amplify-agent/amplify/agent/tanks/objects.py

268 lines
8.5 KiB
Python

# -*- coding: utf-8 -*-
import copy
from collections import defaultdict
from amplify.agent import Singleton
from amplify.agent.common.context import context
__author__ = "Grant Hulegaard"
__copyright__ = "Copyright (C) Nginx, Inc. All rights reserved."
__license__ = ""
__maintainer__ = "Grant Hulegaard"
__email__ = "grant.hulegaard@nginx.com"
# TODO: Add custom exceptions.
class ObjectsTank(Singleton):
"""
Coordinating entity that coordinates running objects by providing interfaces for interacting with the entire
collection of objects. This is a registry only, it does not actually manage or call object methods.
"""
# TODO: Is it possible to refactor our process so that we don't store ID in the object itself? This is repeat info.
def __init__(self):
self._ID_SEQUENCE = 0
self.objects = {}
self.objects_by_type = defaultdict(list)
self.relations = defaultdict(list)
self.root_id = 0 # Integer ID of the "root" object.
@property
def root_object(self):
return self.objects[self.root_id] if self.root_id in self.objects else None
def _get_uid(self):
self._ID_SEQUENCE += 1
return self._ID_SEQUENCE
def _recursive_find_children(self, obj_id):
result = []
for child_id in self.relations[obj_id]:
result.append(child_id)
result + self._recursive_find_children(child_id)
return result
def _recursive_create_struct(self, base_id):
"""
Constructs a tree of objects starting from the base object specified.
:param base_id: Int ID of base object to start tree from.
:return: Dict of objects in a parent-child hierarchy
{
'object': Obj
'children': [
{
'object': Obj,
'children': [
...
]
},
{
'object': Obj,
'children': [
...
]
},
...
]
}
"""
if base_id not in self.objects:
return
template = {
'object': None,
'children': []
}
struct = copy.deepcopy(template)
struct['object'] = self.objects[base_id]
for child_id in self.relations[base_id]:
hierarchy = self._recursive_create_struct(child_id)
if hierarchy:
struct['children'].append(hierarchy)
return struct
def tree(self, base_id=None):
if not base_id:
base_id = self.root_id
return self._recursive_create_struct(base_id)
def register(self, obj, parent_obj=None, parent_id=None):
"""
Registers some object to the tank (adds it).
:param obj: Obj
:param parent_id: Int Assigned ID from ID_SEQUENCE for parent object
"""
obj_id = self._get_uid()
# Set obj.id property to assigned ID.
obj.id = obj_id
# Add object to flat objects store.
self.objects[obj.id] = obj
# Add object_id to object type tracker
self.objects_by_type[obj.type].append(obj.id)
# If detected root object type, set to root.
if obj.type in ('system', 'container'):
self.root_id = obj.id
# Init relation list
self.relations[obj.id]
# Parent handling...
if parent_obj or parent_id:
parent_id = parent_obj.id if parent_obj else parent_id
# If parent_id, add obj_id to appropriate obj list
if parent_id:
self.relations[parent_id].append(obj.id)
context.default_log.debug(
'"%s" object registered with %s (id: %s, name: %s)' % (
obj.type, self.__class__.__name__, obj.id, obj.display_name
)
)
return obj.id
def unregister(self, obj=None, obj_id=None):
"""
Unregisters object (removes it).
:param obj: Obj
:param obj_id: Int Assigned ID from ID_SEQUENCE for object
"""
if obj or obj_id:
obj_id = obj.id if obj else obj_id
obj_name = obj.display_name if obj else obj_id
obj = self.objects[obj_id] if not obj else obj
if not obj or obj_id not in self.objects:
context.default_log.error('failed to unregister object')
context.default_log.debug(
'additional info: (obj: %s, obj_id: %s, name: %s)' % (
obj, obj_id, obj_name)
)
return
# cache relations since it will change as children remove themselves
starting_relations = copy.deepcopy(self.relations[obj_id])
# Recursively unregister children since we will be removing the parent.
for child_id in starting_relations:
self.unregister(obj_id=child_id)
obj_type = obj.type
# stop obj
obj.stop()
# Remove object from flat objects store
del self.objects[obj_id]
# Remove obj_id from type tracker
self.objects_by_type[obj_type].remove(obj_id)
# Remove relation list for object
del self.relations[obj_id]
# Remove obj_id from parent's child list (if any). This means by
# default unregister linearly scans all relations looking for obj_id of
# unregistered object.
for parent_id, children in self.relations.items():
if obj_id in children:
children.remove(obj_id)
break
# If obj_id is root...
if obj_id == self.root_id:
self.root_id = 0
context.default_log.debug(
'"%s" object unregistered with %s (id: %s, name: %s)' % (
obj.type, self.__class__.__name__, obj_id, obj_name
)
)
def find_one(self, obj_id=None):
return self.objects[obj_id] if obj_id in self.objects else None
def find_all(self, obj_id=None, parent_id=None, children=False, types=None, include_self=True):
"""
Returns a list of registered objects meeting criteria. First finds all id's matching criteria and then
:param obj_id: Int Assigned ID of object
:param parent_id: Int Assigned ID of parent object (returns its children)
:param children: Bool Whether or not to return children and children's children of the object as well.
:param types: List/Tuple Iterable of Str object types.
:param include_self: Bool Whether or not to return the primary obj as well.
:return: List of Objects
"""
found_ids = set()
if obj_id and obj_id in self.objects:
found_ids.add(obj_id)
if parent_id and parent_id in self.relations:
for child_id in self.relations[parent_id]:
found_ids.add(child_id)
if children:
for child_id in self._recursive_find_children(obj_id):
if child_id in self.objects:
found_ids.add(child_id)
if types:
for type in types:
for type_id in self.objects_by_type[type]:
if type_id in self.objects:
found_ids.add(type_id)
if not include_self and obj_id in found_ids:
found_ids.remove(obj_id)
return [self.objects[found_id] for found_id in found_ids]
def find_parent(self, obj=None, obj_id=None):
if obj or obj_id:
obj_id = obj.id if obj else obj_id
if not obj_id or obj_id not in self.objects:
context.default_log.error('Failed to find parent object, object not found (obj_id: %s)' % obj_id)
return
found_parent_id = None
for parent_id, children_ids in self.relations.items():
if obj_id in children_ids:
found_parent_id = parent_id
break
# make sure the parent_id is still a valid object
if found_parent_id is not None:
if found_parent_id in self.objects:
return self.objects[found_parent_id]
else:
context.default_log.error(
'Found an invalid parent object_id for child '
'(child_id: %s, parent_id: %s)' % (obj_id, parent_id)
)
return None
# This is one of those situations where an action might release the
# GIL for an extended time, during which an object gets removed
else:
return None