feat: store manager basic implementation

Refs: OPS-16

senju/store_manager.py

@@ -0,0 +1,50 @@
+from typing import Optional
+from tinydb import TinyDB, Query
+from uuid import UUID, uuid1
+from pathlib import Path
+import time
+
+from tinydb.queries import QueryImpl
+
+DEFAULT_DB_PATH: Path = Path("/var/lib/senju.json")
+
+
+class StoreManager:
+    __slots__ = "_db"
+    _db: TinyDB
+
+    def __init__(self, path_to_db: Path = DEFAULT_DB_PATH) -> None:
+        self._db = TinyDB(path_to_db)
+
+    def new_id(self) -> UUID:
+        unix_timestamp: int = int(time.time())
+        _guard: int = 0
+        while True:
+            id = uuid1(node=None, clock_seq=unix_timestamp)
+            if len(self._query(Query().id == id)) > 0:
+                break
+            _guard += 1
+            if _guard > 100:
+                raise Exception(
+                    "tried 100 random UUIDs but found no unused one")
+        return id
+
+    def _query(self, query: QueryImpl) -> list[dict]:
+        return self._db.search(query)
+
+    def load(self, key: UUID) -> Optional[dict]:
+        results = self._query(Query().id == key)
+        if len(results) < 1:
+            raise Exception("foobar")
+        elif len(results) > 2:
+            raise KeyError("The requested item did not exist in our database")
+        else:
+            return results[0]
+
+    def save(self, data: dict) -> UUID:
+        id = self.new_id()
+        self._db.insert({
+            "id": id,
+            "data": data
+        })
+        return id