cleaned up singleton notebook

Singleton.ipynb

@@ -0,0 +1,168 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Pure Python Metaclass"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Initializing singleton: 21aac41a-ee95-40c0-88f1-f55eaf81ac60\n",
+      "MySingleton(uuid=UUID('21aac41a-ee95-40c0-88f1-f55eaf81ac60'))\n",
+      "MySingleton(uuid=UUID('21aac41a-ee95-40c0-88f1-f55eaf81ac60'))\n",
+      "MySingleton(uuid=UUID('21aac41a-ee95-40c0-88f1-f55eaf81ac60'))\n",
+      "MySingleton(uuid=UUID('21aac41a-ee95-40c0-88f1-f55eaf81ac60'))\n",
+      "MySingleton(uuid=UUID('21aac41a-ee95-40c0-88f1-f55eaf81ac60'))\n"
+     ]
+    }
+   ],
+   "source": [
+    "from dataclasses import dataclass, field\n",
+    "from uuid import UUID, uuid4\n",
+    "\n",
+    "\n",
+    "# Metaclass definition\n",
+    "class Singleton(type):\n",
+    "    _instances = {}\n",
+    "\n",
+    "    def __call__(cls, *args, **kwargs):\n",
+    "        if cls not in cls._instances:\n",
+    "            cls._instances[cls] = super().__call__(*args, **kwargs)\n",
+    "        return cls._instances[cls]\n",
+    "\n",
+    "\n",
+    "# gives an example of inheritance\n",
+    "@dataclass\n",
+    "class ParentClass:\n",
+    "    uuid: UUID = field(init=False, default_factory=uuid4)\n",
+    "\n",
+    "\n",
+    "# Main singleton class\n",
+    "@dataclass\n",
+    "class MySingleton(ParentClass, metaclass=Singleton):\n",
+    "    def __post_init__(self):\n",
+    "        print(f'Initializing singleton: {self.uuid}')\n",
+    "\n",
+    "\n",
+    "# Initialize the singleton\n",
+    "MySingleton()\n",
+    "\n",
+    "# \"Initialize\" a few more times\n",
+    "for _ in range(5):\n",
+    "    print(MySingleton())"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Pydantic Metaclass"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "from typing import Any, Optional, Self\n",
+    "\n",
+    "from pydantic import BaseModel, Field\n",
+    "from pydantic._internal._model_construction import ModelMetaclass\n",
+    "\n",
+    "\n",
+    "class PydanticSingleton(ModelMetaclass):\n",
+    "    _instances = {}\n",
+    "\n",
+    "    def __call__(cls, *args, **kwargs):\n",
+    "        if model := cls._instances.get(cls):\n",
+    "            model_dict = model.model_dump()\n",
+    "            model_dict.update(kwargs)\n",
+    "            model = model.model_validate(model_dict)\n",
+    "            cls._instances[cls] = model\n",
+    "        else:\n",
+    "            cls._instances[cls] = super(PydanticSingleton, cls).__call__(*args, **kwargs)\n",
+    "\n",
+    "        return cls._instances[cls]\n",
+    "\n",
+    "\n",
+    "class MyPydanticSingleton(BaseModel, metaclass=PydanticSingleton):\n",
+    "    id: UUID = Field(default_factory=uuid4)\n",
+    "    required_field: str\n",
+    "    foo: Optional[str] = None"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 3,
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "id=UUID('9965c864-20b7-4809-b73a-c16c352fea20') required_field='Iteration 0' foo=None\n",
+      "id=UUID('9965c864-20b7-4809-b73a-c16c352fea20') required_field='Iteration 1' foo=None\n",
+      "id=UUID('9965c864-20b7-4809-b73a-c16c352fea20') required_field='Iteration 2' foo=None\n",
+      "id=UUID('9965c864-20b7-4809-b73a-c16c352fea20') required_field='Iteration 3' foo=None\n",
+      "id=UUID('9965c864-20b7-4809-b73a-c16c352fea20') required_field='Iteration 4' foo=None\n"
+     ]
+    }
+   ],
+   "source": [
+    "s = [MyPydanticSingleton(required_field=f'Iteration {i}') for i in range(5)]\n",
+    "print('\\n'.join(map(str, s)))"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 4,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/plain": [
+       "MyPydanticSingleton(id=UUID('9965c864-20b7-4809-b73a-c16c352fea20'), required_field='Iteration 4', foo='bar')"
+      ]
+     },
+     "execution_count": 4,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "MyPydanticSingleton(foo='bar')"
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "appdaemon",
+   "language": "python",
+   "name": "python3"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 3
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython3",
+   "version": "3.11.8"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 2
+}