add memory storage (#3)

Co-authored-by: Tamirlan Dzhemirzoev <tamirlan.dzhemirzoev@ccsteam.ru>

Author: d-tamirlan

botx_fsm/storages/memory.py

@@ -0,0 +1,43 @@
+import pickle
+from datetime import timedelta
+from enum import Enum
+from typing import Any, Union
+
+from cachetools import TTLCache
+
+from botx_fsm import Key, unset
+from botx_fsm.markers import FSMStateMarker
+from botx_fsm.storages.base import BaseStorage, StateInStorage
+
+ONE_WEEK = timedelta(weeks=1).total_seconds()
+ONE_MB = 1024 * 1024
+
+
+class MemoryStorage(BaseStorage):
+    storage: TTLCache
+
+    def __init__(self, maxsize: int = ONE_MB, expire_time: int = ONE_WEEK) -> None:
+        self.storage = TTLCache(maxsize=maxsize, ttl=expire_time,)
+
+    async def get_state(self, key: Key) -> StateInStorage:
+        saved_value = self.storage.get(key.to_json())
+        if saved_value is None:
+            return unset
+
+        restored_value = pickle.loads(saved_value)  # noqa: S301
+        if not isinstance(restored_value, StateInStorage):
+            raise RuntimeError("received not Enum instance from storage")
+
+        return restored_value
+
+    async def change_state(
+        self, key: Key, state: Union[Enum, FSMStateMarker], **kwargs: Any
+    ) -> None:
+        memory_key = key.to_json()
+        if state is unset:
+            del self.storage[memory_key]
+            return
+
+        self.storage[memory_key] = pickle.dumps(
+            StateInStorage(state=state, kwargs=kwargs)
+        )

poetry.lock

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "botx-fsm"
-version = "0.1.5"
+version = "0.1.6"
 description = "FSM middleware for using with pybotx"
 authors = ["Nik Sidnev <sidnev.nick@gmail.com>"]
 
@@ -10,6 +10,7 @@ python = "^3.7"
 botx = ">=0.17.0, <0.21.0"
 aioredis = "^1.3.1"
 async_lru = "^1.0.2"
+cachetools = "^4.2.2"
 
 [tool.poetry.dev-dependencies]
 black = "^19.10b0"