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    "## Retry function call with context manager\n",
    "\n",
    "### Goal\n",
    "\n",
    "A function call may fail due to a temporal issue, for instance, a request call\n",
    "to an external URL. In this case, it may be useful, to retry calling that function\n",
    "multiple times in sequence, and only raising an error if all retries fail.\n",
    "\n",
    "### The retry module\n",
    "\n",
    "The [retry][retry] package provides a convenient method [retry_call][retry_call], which calls\n",
    "a function either up until the amount of ``retries`` is reached or to be retried function\n",
    "returns a non-error type object.\n",
    "\n",
    "[retry]: https://pypi.org/project/retry2/\n",
    "[retry_call]: https://github.com/eSAMTrade/retry#retry_call"
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   "source": [
    "from retry.api import retry_call\n",
    "\n",
    "def say_hi():\n",
    "    print(\"hi\")\n",
    "    raise OSError\n",
    "\n",
    "\n",
    "def retry_say_hi():\n",
    "    exceptions = (OSError, IOError,)\n",
    "    try:\n",
    "        retry_call(say_hi, tries=3)\n",
    "    except exceptions:\n",
    "        print(\"That didn't go well\")\n",
    "\n",
    "\n",
    "if __name__ == \"__main__\":\n",
    "    retry_say_hi()"
   ],
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    "The above function call of `retry_say_hi()` enters `say_hi()` three times, each time raising a `OSError`, which causes a retry, and ultimately fails.\n",
    "\n",
    "### Wrapping retry in a context manager\n",
    "\n",
    "To provide a uniform way to retry sensitive functions, a [context manager] can be used to wrap a to-be-retried-in-error-case function:"
   ],
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   "source": [
    "from typing import Tuple, Type\n",
    "from logging import Logger\n",
    "from contextlib import contextmanager\n",
    "from dataclasses import dataclass\n",
    "from functools import partial\n",
    "\n",
    "\n",
    "@dataclass\n",
    "class RetryContextManager:\n",
    "    \"\"\"Context manager to *retry* calls.\n",
    "\n",
    "    The class wraps the methods provided by the `retry` Python package\n",
    "    to simplify the retry of failing function calls. The class implements\n",
    "    a context manager that allows us to specify retry parameters once\n",
    "    at init time.\n",
    "    \"\"\"\n",
    "\n",
    "    exceptions: Tuple[Type[Exception], ...] = (Exception,)\n",
    "    tries: int = 1\n",
    "    delay: int = 0\n",
    "    max_delay: int = None\n",
    "    backoff: int = 1\n",
    "    jitter: Tuple[int, int] = (0, 0)\n",
    "    logger: Logger = None\n",
    "\n",
    "    @contextmanager\n",
    "    def retry(self, f, *fargs, **fkwargs):\n",
    "        yield partial(\n",
    "            retry_call, f, fargs, fkwargs,\n",
    "            exceptions=self.exceptions,\n",
    "            tries=self.tries,\n",
    "            delay=self.delay,\n",
    "            max_delay=self.max_delay,\n",
    "            backoff=self.backoff,\n",
    "            jitter=self.jitter,\n",
    "            logger=self.logger\n",
    "        )"
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    "**Line 9-24**: Definition of the `RetryContextManager` dataclass\n",
    "\n",
    "**Line 26-36**: Definition of the context manager factory function. The `@contextmanager` decorator\n",
    "enables to define a function as context manager, instead of a class implementing the `__enter__()`\n",
    "and `__exit__()` method. It returns the `retry_call` method as *partial object*, which behaves like\n",
    "the regular method would, but passes in the arguments from the `RetryContextManager` instance it is\n",
    "called from. The [partial][partial] method allows calling the function (here: `retry_call`) with\n",
    "custom positional arguments.\n",
    "\n",
    "[partial]: https://docs.python.org/3/library/functools.html#functools.partial\n",
    "\n",
    "### Using the custom context manager\n",
    "\n",
    "A class may now define a custom `RetryContextManager`, specifying custom `tries` or `delay` parameters"
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   "source": [
    "import logging\n",
    "import requests\n",
    "\n",
    "class MyRequestClass:\n",
    "\n",
    "    def __init__(self):\n",
    "        self.get_response_retry_ctx = RetryContextManager(\n",
    "            tries=3,\n",
    "            delay=1,\n",
    "            exceptions=(requests.RequestException,),\n",
    "            logger=logging.getLogger(\"RobotFramework\")\n",
    "        )\n",
    "\n",
    "    def get_audio_bytes_from_url(self, url: str) -> bytes:\n",
    "        with self.get_response_retry_ctx.retry(requests.get,\n",
    "                                               url) as get_response:\n",
    "            response = get_response()\n",
    "        if response.status_code == 200:\n",
    "            print(\"That went well\")\n",
    "        else:\n",
    "            raise ConnectionError(f\"Unable to receive content from {url}\")"
   ],
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   "source": [
    "**Line 7**: An instance of `RetryContextManager` dataclass which contains the `retry`\n",
    "context manager method is defined.\n",
    "\n",
    "**Line 15 & 16**: The `retry` context manager is entered, passing in `requests.get` as \n",
    "the function to be called and `url` as a function argument (which leads to the function\n",
    "call `requests.get(url)`) an assigning the function call to `get_response`.\n",
    "\n",
    "**Line 17**: The `get_response` function is called. Afterward, the context manager is closed."
   ],
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