559 lines
20 KiB
Python
559 lines
20 KiB
Python
from collections import defaultdict
|
|
from typing import (
|
|
TYPE_CHECKING,
|
|
Any,
|
|
Dict,
|
|
Iterable,
|
|
List,
|
|
Optional,
|
|
Set,
|
|
Tuple,
|
|
)
|
|
|
|
from django.apps import apps
|
|
from typing_extensions import Protocol
|
|
|
|
from .redis import use_redis
|
|
from .utils import split_element_id, str_dict_to_bytes
|
|
|
|
|
|
if use_redis:
|
|
from .redis import get_connection, aioredis
|
|
|
|
|
|
if TYPE_CHECKING:
|
|
# Dummy import Collection for mypy, can be fixed with python 3.7
|
|
from .collection import CollectionElement # noqa
|
|
|
|
|
|
class ElementCacheProvider(Protocol):
|
|
"""
|
|
Base class for cache provider.
|
|
|
|
See RedisCacheProvider as reverence implementation.
|
|
"""
|
|
|
|
async def clear_cache(self) -> None: ...
|
|
|
|
async def reset_full_cache(self, data: Dict[str, str]) -> None: ...
|
|
|
|
async def data_exists(self, user_id: Optional[int] = None) -> bool: ...
|
|
|
|
async def add_elements(self, elements: List[str]) -> None: ...
|
|
|
|
async def del_elements(self, elements: List[str], user_id: Optional[int] = None) -> None: ...
|
|
|
|
async def add_changed_elements(self, default_change_id: int, element_ids: Iterable[str]) -> int: ...
|
|
|
|
async def get_all_data(self, user_id: Optional[int] = None) -> Dict[bytes, bytes]: ...
|
|
|
|
async def get_data_since(
|
|
self,
|
|
change_id: int,
|
|
user_id: Optional[int] = None,
|
|
max_change_id: int = -1) -> Tuple[Dict[str, List[bytes]], List[str]]: ...
|
|
|
|
async def get_element(self, element_id: str, user_id: Optional[int] = None) -> Optional[bytes]: ...
|
|
|
|
async def del_restricted_data(self, user_id: int) -> None: ...
|
|
|
|
async def set_lock(self, lock_name: str) -> bool: ...
|
|
|
|
async def get_lock(self, lock_name: str) -> bool: ...
|
|
|
|
async def del_lock(self, lock_name: str) -> None: ...
|
|
|
|
async def get_change_id_user(self, user_id: int) -> Optional[int]: ...
|
|
|
|
async def update_restricted_data(self, user_id: int, data: Dict[str, str]) -> None: ...
|
|
|
|
async def get_current_change_id(self) -> List[Tuple[str, int]]: ...
|
|
|
|
async def get_lowest_change_id(self) -> Optional[int]: ...
|
|
|
|
|
|
class RedisCacheProvider:
|
|
"""
|
|
Cache provider that loads and saves the data to redis.
|
|
"""
|
|
full_data_cache_key: str = 'full_data'
|
|
restricted_user_cache_key: str = 'restricted_data:{user_id}'
|
|
change_id_cache_key: str = 'change_id'
|
|
prefix: str = 'element_cache_'
|
|
|
|
def get_full_data_cache_key(self) -> str:
|
|
return "".join((self.prefix, self.full_data_cache_key))
|
|
|
|
def get_restricted_data_cache_key(self, user_id: int) -> str:
|
|
return "".join((self.prefix, self.restricted_user_cache_key.format(user_id=user_id)))
|
|
|
|
def get_change_id_cache_key(self) -> str:
|
|
return "".join((self.prefix, self.change_id_cache_key))
|
|
|
|
async def clear_cache(self) -> None:
|
|
"""
|
|
Deleted all cache entries created with this element cache.
|
|
"""
|
|
async with get_connection() as redis:
|
|
await redis.eval("return redis.call('del', 'fake_key', unpack(redis.call('keys', ARGV[1])))", keys=[], args=["{}*".format(self.prefix)])
|
|
|
|
async def reset_full_cache(self, data: Dict[str, str]) -> None:
|
|
"""
|
|
Deletes the full_data_cache and write new data in it.
|
|
|
|
Also deletes the restricted_data_cache and the change_id_cache.
|
|
"""
|
|
async with get_connection() as redis:
|
|
tr = redis.multi_exec()
|
|
# like clear_cache but does not delete a lock
|
|
tr.eval(
|
|
"return redis.call('del', 'fake_key', unpack(redis.call('keys', ARGV[1])))",
|
|
keys=[],
|
|
args=["{}{}*".format(self.prefix, self.restricted_user_cache_key)])
|
|
tr.delete(self.get_change_id_cache_key())
|
|
tr.delete(self.get_full_data_cache_key())
|
|
tr.hmset_dict(self.get_full_data_cache_key(), data)
|
|
await tr.execute()
|
|
|
|
async def data_exists(self, user_id: Optional[int] = None) -> bool:
|
|
"""
|
|
Returns True, when there is data in the cache.
|
|
|
|
If user_id is None, the method tests for full_data. If user_id is an int, it tests
|
|
for the restricted_data_cache for the user with the user_id. 0 is for anonymous.
|
|
"""
|
|
async with get_connection() as redis:
|
|
if user_id is None:
|
|
cache_key = self.get_full_data_cache_key()
|
|
else:
|
|
cache_key = self.get_restricted_data_cache_key(user_id)
|
|
return await redis.exists(cache_key)
|
|
|
|
async def add_elements(self, elements: List[str]) -> None:
|
|
"""
|
|
Add or change elements to the cache.
|
|
|
|
elements is a list with an even len. the odd values are the element_ids and the even
|
|
values are the elements. The elements have to be encoded, for example with json.
|
|
"""
|
|
async with get_connection() as redis:
|
|
await redis.hmset(
|
|
self.get_full_data_cache_key(),
|
|
*elements)
|
|
|
|
async def del_elements(self, elements: List[str], user_id: Optional[int] = None) -> None:
|
|
"""
|
|
Deletes elements from the cache.
|
|
|
|
elements has to be a list of element_ids.
|
|
|
|
If user_id is None, the elements are deleted from the full_data cache. If user_id is an
|
|
int, the elements are deleted one restricted_data_cache. 0 is for anonymous.
|
|
"""
|
|
async with get_connection() as redis:
|
|
if user_id is None:
|
|
cache_key = self.get_full_data_cache_key()
|
|
else:
|
|
cache_key = self.get_restricted_data_cache_key(user_id)
|
|
await redis.hdel(
|
|
cache_key,
|
|
*elements)
|
|
|
|
async def add_changed_elements(self, default_change_id: int, element_ids: Iterable[str]) -> int:
|
|
"""
|
|
Saves which elements are change with a change_id.
|
|
|
|
Generates and returns the change_id.
|
|
"""
|
|
async with get_connection() as redis:
|
|
return int(await redis.eval(
|
|
lua_script_change_data,
|
|
keys=[self.get_change_id_cache_key()],
|
|
args=[default_change_id, *element_ids]
|
|
))
|
|
|
|
async def get_all_data(self, user_id: Optional[int] = None) -> Dict[bytes, bytes]:
|
|
"""
|
|
Returns all data from a cache.
|
|
|
|
if user_id is None, then the data is returned from the full_data_cache. If it is and
|
|
int, it is returned from a restricted_data_cache. 0 is for anonymous.
|
|
"""
|
|
if user_id is None:
|
|
cache_key = self.get_full_data_cache_key()
|
|
else:
|
|
cache_key = self.get_restricted_data_cache_key(user_id)
|
|
|
|
async with get_connection() as redis:
|
|
return await redis.hgetall(cache_key)
|
|
|
|
async def get_element(self, element_id: str, user_id: Optional[int] = None) -> Optional[bytes]:
|
|
"""
|
|
Returns one element from the cache.
|
|
|
|
Returns None, when the element does not exist.
|
|
"""
|
|
if user_id is None:
|
|
cache_key = self.get_full_data_cache_key()
|
|
else:
|
|
cache_key = self.get_restricted_data_cache_key(user_id)
|
|
|
|
async with get_connection() as redis:
|
|
return await redis.hget(
|
|
cache_key,
|
|
element_id)
|
|
|
|
async def get_data_since(
|
|
self,
|
|
change_id: int,
|
|
user_id: Optional[int] = None,
|
|
max_change_id: int = -1) -> Tuple[Dict[str, List[bytes]], List[str]]:
|
|
"""
|
|
Returns all elements since a change_id.
|
|
|
|
The returend value is a two element tuple. The first value is a dict the elements where
|
|
the key is the collection_string and the value a list of (json-) encoded elements. The
|
|
second element is a list of element_ids, that have been deleted since the change_id.
|
|
|
|
if user_id is None, the full_data is returned. If user_id is an int, the restricted_data
|
|
for an user is used. 0 is for the anonymous user.
|
|
"""
|
|
changed_elements: Dict[str, List[bytes]] = defaultdict(list)
|
|
deleted_elements: List[str] = []
|
|
if user_id is None:
|
|
cache_key = self.get_full_data_cache_key()
|
|
else:
|
|
cache_key = self.get_restricted_data_cache_key(user_id)
|
|
|
|
# Convert max_change_id to a string. If its negative, use the string '+inf'
|
|
redis_max_change_id = "+inf" if max_change_id < 0 else str(max_change_id)
|
|
async with get_connection() as redis:
|
|
# lua script that returns gets all element_ids from change_id_cache_key
|
|
# and then uses each element_id on full_data or restricted_data.
|
|
# It returns a list where the odd values are the change_id and the
|
|
# even values the element as json. The function wait_make_dict creates
|
|
# a python dict from the returned list.
|
|
elements: Dict[bytes, Optional[bytes]] = await aioredis.util.wait_make_dict(redis.eval(
|
|
"""
|
|
-- Get change ids of changed elements
|
|
local element_ids = redis.call('zrangebyscore', KEYS[1], ARGV[1], ARGV[2])
|
|
|
|
-- Save elements in array. Rotate element_id and element_json
|
|
local elements = {}
|
|
for _, element_id in pairs(element_ids) do
|
|
table.insert(elements, element_id)
|
|
table.insert(elements, redis.call('hget', KEYS[2], element_id))
|
|
end
|
|
return elements
|
|
""",
|
|
keys=[self.get_change_id_cache_key(), cache_key],
|
|
args=[change_id, redis_max_change_id]))
|
|
|
|
for element_id, element_json in elements.items():
|
|
if element_id.startswith(b'_config'):
|
|
# Ignore config values from the change_id cache key
|
|
continue
|
|
if element_json is None:
|
|
# The element is not in the cache. It has to be deleted.
|
|
deleted_elements.append(element_id.decode())
|
|
else:
|
|
collection_string, id = split_element_id(element_id)
|
|
changed_elements[collection_string].append(element_json)
|
|
return changed_elements, deleted_elements
|
|
|
|
async def del_restricted_data(self, user_id: int) -> None:
|
|
"""
|
|
Deletes all restricted_data for an user. 0 is for the anonymous user.
|
|
"""
|
|
async with get_connection() as redis:
|
|
await redis.delete(self.get_restricted_data_cache_key(user_id))
|
|
|
|
async def set_lock(self, lock_name: str) -> bool:
|
|
"""
|
|
Tries to sets a lock.
|
|
|
|
Returns True when the lock could be set.
|
|
|
|
Returns False when the lock was already set.
|
|
"""
|
|
# TODO: Improve lock. See: https://redis.io/topics/distlock
|
|
async with get_connection() as redis:
|
|
return await redis.setnx("{}lock_{}".format(self.prefix, lock_name), 1)
|
|
|
|
async def get_lock(self, lock_name: str) -> bool:
|
|
"""
|
|
Returns True, when the lock for the restricted_data of an user is set. Else False.
|
|
"""
|
|
async with get_connection() as redis:
|
|
return await redis.get("{}lock_{}".format(self.prefix, lock_name))
|
|
|
|
async def del_lock(self, lock_name: str) -> None:
|
|
"""
|
|
Deletes the lock for the restricted_data of an user. Does nothing when the
|
|
lock is not set.
|
|
"""
|
|
async with get_connection() as redis:
|
|
await redis.delete("{}lock_{}".format(self.prefix, lock_name))
|
|
|
|
async def get_change_id_user(self, user_id: int) -> Optional[int]:
|
|
"""
|
|
Get the change_id for the restricted_data of an user.
|
|
|
|
This is the change_id where the restricted_data was last calculated.
|
|
"""
|
|
async with get_connection() as redis:
|
|
return await redis.hget(self.get_restricted_data_cache_key(user_id), '_config:change_id')
|
|
|
|
async def update_restricted_data(self, user_id: int, data: Dict[str, str]) -> None:
|
|
"""
|
|
Updates the restricted_data for an user.
|
|
|
|
data has to be a dict where the key is an element_id and the value the (json-) encoded
|
|
element.
|
|
"""
|
|
async with get_connection() as redis:
|
|
await redis.hmset_dict(self.get_restricted_data_cache_key(user_id), data)
|
|
|
|
async def get_current_change_id(self) -> List[Tuple[str, int]]:
|
|
"""
|
|
Get the highest change_id from redis.
|
|
"""
|
|
async with get_connection() as redis:
|
|
return await redis.zrevrangebyscore(
|
|
self.get_change_id_cache_key(),
|
|
withscores=True,
|
|
count=1,
|
|
offset=0)
|
|
|
|
async def get_lowest_change_id(self) -> Optional[int]:
|
|
"""
|
|
Get the lowest change_id from redis.
|
|
|
|
Returns None if lowest score does not exist.
|
|
"""
|
|
async with get_connection() as redis:
|
|
return await redis.zscore(
|
|
self.get_change_id_cache_key(),
|
|
'_config:lowest_change_id')
|
|
|
|
|
|
class MemmoryCacheProvider:
|
|
"""
|
|
CacheProvider for the ElementCache that uses only the memory.
|
|
|
|
See the RedisCacheProvider for a description of the methods.
|
|
|
|
This provider supports only one process. It saves the data into the memory.
|
|
When you use different processes they will use diffrent data.
|
|
"""
|
|
|
|
def __init__(self) -> None:
|
|
self.set_data_dicts()
|
|
|
|
def set_data_dicts(self) -> None:
|
|
self.full_data: Dict[str, str] = {}
|
|
self.restricted_data: Dict[int, Dict[str, str]] = {}
|
|
self.change_id_data: Dict[int, Set[str]] = {}
|
|
self.locks: Dict[str, str] = {}
|
|
|
|
async def clear_cache(self) -> None:
|
|
self.set_data_dicts()
|
|
|
|
async def reset_full_cache(self, data: Dict[str, str]) -> None:
|
|
self.full_data = data
|
|
|
|
async def data_exists(self, user_id: Optional[int] = None) -> bool:
|
|
if user_id is None:
|
|
cache_dict = self.full_data
|
|
else:
|
|
cache_dict = self.restricted_data.get(user_id, {})
|
|
|
|
return bool(cache_dict)
|
|
|
|
async def add_elements(self, elements: List[str]) -> None:
|
|
if len(elements) % 2:
|
|
raise ValueError("The argument elements of add_elements has to be a list with an even number of elements.")
|
|
|
|
for i in range(0, len(elements), 2):
|
|
self.full_data[elements[i]] = elements[i+1]
|
|
|
|
async def del_elements(self, elements: List[str], user_id: Optional[int] = None) -> None:
|
|
if user_id is None:
|
|
cache_dict = self.full_data
|
|
else:
|
|
cache_dict = self.restricted_data.get(user_id, {})
|
|
|
|
for element in elements:
|
|
try:
|
|
del cache_dict[element]
|
|
except KeyError:
|
|
pass
|
|
|
|
async def add_changed_elements(self, default_change_id: int, element_ids: Iterable[str]) -> int:
|
|
element_ids = list(element_ids)
|
|
try:
|
|
change_id = (await self.get_current_change_id())[0][1] + 1
|
|
except IndexError:
|
|
change_id = default_change_id
|
|
|
|
for element_id in element_ids:
|
|
if change_id in self.change_id_data:
|
|
self.change_id_data[change_id].add(element_id)
|
|
else:
|
|
self.change_id_data[change_id] = {element_id}
|
|
return change_id
|
|
|
|
async def get_all_data(self, user_id: Optional[int] = None) -> Dict[bytes, bytes]:
|
|
if user_id is None:
|
|
cache_dict = self.full_data
|
|
else:
|
|
cache_dict = self.restricted_data.get(user_id, {})
|
|
|
|
return str_dict_to_bytes(cache_dict)
|
|
|
|
async def get_element(self, element_id: str, user_id: Optional[int] = None) -> Optional[bytes]:
|
|
if user_id is None:
|
|
cache_dict = self.full_data
|
|
else:
|
|
cache_dict = self.restricted_data.get(user_id, {})
|
|
|
|
value = cache_dict.get(element_id, None)
|
|
return value.encode() if value is not None else None
|
|
|
|
async def get_data_since(
|
|
self,
|
|
change_id: int,
|
|
user_id: Optional[int] = None,
|
|
max_change_id: int = -1) -> Tuple[Dict[str, List[bytes]], List[str]]:
|
|
changed_elements: Dict[str, List[bytes]] = defaultdict(list)
|
|
deleted_elements: List[str] = []
|
|
if user_id is None:
|
|
cache_dict = self.full_data
|
|
else:
|
|
cache_dict = self.restricted_data.get(user_id, {})
|
|
|
|
for data_change_id, element_ids in self.change_id_data.items():
|
|
if data_change_id < change_id or (max_change_id > -1 and data_change_id > max_change_id):
|
|
continue
|
|
for element_id in element_ids:
|
|
element_json = cache_dict.get(element_id, None)
|
|
if element_json is None:
|
|
deleted_elements.append(element_id)
|
|
else:
|
|
collection_string, id = split_element_id(element_id)
|
|
changed_elements[collection_string].append(element_json.encode())
|
|
return changed_elements, deleted_elements
|
|
|
|
async def del_restricted_data(self, user_id: int) -> None:
|
|
try:
|
|
del self.restricted_data[user_id]
|
|
except KeyError:
|
|
pass
|
|
|
|
async def set_lock(self, lock_name: str) -> bool:
|
|
if lock_name in self.locks:
|
|
return False
|
|
self.locks[lock_name] = "1"
|
|
return True
|
|
|
|
async def get_lock(self, lock_name: str) -> bool:
|
|
return lock_name in self.locks
|
|
|
|
async def del_lock(self, lock_name: str) -> None:
|
|
try:
|
|
del self.locks[lock_name]
|
|
except KeyError:
|
|
pass
|
|
|
|
async def get_change_id_user(self, user_id: int) -> Optional[int]:
|
|
data = self.restricted_data.get(user_id, {})
|
|
change_id = data.get('_config:change_id', None)
|
|
return int(change_id) if change_id is not None else None
|
|
|
|
async def update_restricted_data(self, user_id: int, data: Dict[str, str]) -> None:
|
|
redis_data = self.restricted_data.setdefault(user_id, {})
|
|
redis_data.update(data)
|
|
|
|
async def get_current_change_id(self) -> List[Tuple[str, int]]:
|
|
change_data = self.change_id_data
|
|
if change_data:
|
|
return [('no_usefull_value', max(change_data.keys()))]
|
|
return []
|
|
|
|
async def get_lowest_change_id(self) -> Optional[int]:
|
|
change_data = self.change_id_data
|
|
if change_data:
|
|
return min(change_data.keys())
|
|
return None
|
|
|
|
|
|
class Cachable(Protocol):
|
|
"""
|
|
A Cachable is an object that returns elements that can be cached.
|
|
|
|
It needs at least the methods defined here.
|
|
"""
|
|
|
|
def get_collection_string(self) -> str:
|
|
"""
|
|
Returns the string representing the name of the cachable.
|
|
"""
|
|
|
|
def get_elements(self) -> List[Dict[str, Any]]:
|
|
"""
|
|
Returns all elements of the cachable.
|
|
"""
|
|
|
|
async def restrict_elements(
|
|
self,
|
|
user: Optional['CollectionElement'],
|
|
elements: List[Dict[str, Any]]) -> List[Dict[str, Any]]:
|
|
"""
|
|
Converts full_data to restricted_data.
|
|
|
|
elements can be an empty list, a list with some elements of the cachable or with all
|
|
elements of the cachable.
|
|
"""
|
|
|
|
|
|
def get_all_cachables() -> List[Cachable]:
|
|
"""
|
|
Returns all element of OpenSlides.
|
|
"""
|
|
out: List[Cachable] = []
|
|
for app in apps.get_app_configs():
|
|
try:
|
|
# Get the method get_startup_elements() from an app.
|
|
# This method has to return an iterable of Cachable objects.
|
|
get_startup_elements = app.get_startup_elements
|
|
except AttributeError:
|
|
# Skip apps that do not implement get_startup_elements.
|
|
continue
|
|
out.extend(get_startup_elements())
|
|
return out
|
|
|
|
|
|
lua_script_change_data = """
|
|
-- Generate a new change_id
|
|
local tmp = redis.call('zrevrangebyscore', KEYS[1], '+inf', '-inf', 'WITHSCORES', 'LIMIT', 0, 1)
|
|
local change_id
|
|
if next(tmp) == nil then
|
|
-- The key does not exist
|
|
change_id = ARGV[1]
|
|
else
|
|
change_id = tmp[2] + 1
|
|
end
|
|
|
|
-- Add elements to sorted set
|
|
local count = 2
|
|
while ARGV[count] do
|
|
redis.call('zadd', KEYS[1], change_id, ARGV[count])
|
|
count = count + 1
|
|
end
|
|
|
|
-- Set lowest_change_id if it does not exist
|
|
redis.call('zadd', KEYS[1], 'NX', change_id, '_config:lowest_change_id')
|
|
|
|
return change_id
|
|
"""
|