async_decorator.ipynb

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   "source": [
    "import asyncio\n",
    "from functools import wraps, partial\n",
    "import time"
   ]
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    "# Synchronous\n",
    "\n",
    "Each call blocks, so we can only run sequentially."
   ]
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     "text": [
      "Starting thing 1\n",
      "Finished thing 1\n",
      "Starting thing 2\n",
      "Finished thing 2\n",
      "Starting thing 3\n",
      "Finished thing 3\n"
     ]
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       "[1, 2, 3]"
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   "source": [
    "def do_slow_thing(sleep_time):\n",
    "    \"\"\"Some function that takes a while, maybe hits the tiled server.\"\"\"\n",
    "    print(f\"Starting thing {sleep_time}\")\n",
    "    time.sleep(sleep_time)\n",
    "    print(f\"Finished thing {sleep_time}\")\n",
    "    return sleep_time\n",
    "\n",
    "[\n",
    "    do_slow_thing(1),\n",
    "    do_slow_thing(2),\n",
    "    do_slow_thing(3),\n",
    "]"
   ]
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    "# With an Async Decorator\n",
    "\n",
    "With a decorator, we can make the existing synchronous functions run in a thread and be awaitable. Using ``asyncio.gather`` we can then run them at the same time and get the result."
   ]
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      "Starting thing 1\n",
      "Starting thing 2\n",
      "Starting thing 3\n",
      "Finished thing 1\n",
      "Finished thing 2\n",
      "Finished thing 3\n"
     ]
    },
    {
     "data": {
      "text/plain": [
       "[1, 2, 3]"
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     "execution_count": 28,
     "metadata": {},
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   "source": [
    "def awaitable(fn):\n",
    "    \"\"\"Makes the wrapped function awaitable by running it in a separate thread.\"\"\"\n",
    "    @wraps(fn)\n",
    "    async def inner(*args, **kwargs):\n",
    "        # Create a new partial so we can run it in a new thread\n",
    "        new_fn = partial(fn, *args, **kwargs)\n",
    "        # Execute the wrapped function in a thread\n",
    "        loop = asyncio.get_running_loop()\n",
    "        return await loop.run_in_executor(None, new_fn)\n",
    "    return inner\n",
    "\n",
    "@awaitable\n",
    "def do_slow_thing(sleep_time):\n",
    "    \"\"\"Some function that takes a while, maybe hits the tiled server.\"\"\"\n",
    "    print(f\"Starting thing {sleep_time}\")\n",
    "    time.sleep(sleep_time)\n",
    "    print(f\"Finished thing {sleep_time}\")\n",
    "    return sleep_time\n",
    "\n",
    "# Now execute a few of the slow things together\n",
    "await asyncio.gather(do_slow_thing(1), do_slow_thing(2), do_slow_thing(3))"
   ]
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