history-logging.ipynb

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   "source": [
    "## Reproducible history logging via decorators and docstrings"
   ]
  },
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   "source": [
    "import os\n",
    "import re\n",
    "import sys\n",
    "import logging\n",
    "import inspect\n",
    "\n",
    "log = logging.getLogger(\"history\")\n",
    "log.setLevel(logging.INFO)\n",
    "\n",
    "filename = 'history.py'\n",
    "if os.path.exists(filename):\n",
    "    os.remove(filename)\n",
    "\n",
    "file_handler = logging.FileHandler(filename=filename, mode='a')\n",
    "file_handler.setFormatter(logging.Formatter())\n",
    "log.addHandler(file_handler)\n",
    "\n",
    "stream_handler = logging.StreamHandler(sys.stdout)\n",
    "log.addHandler(stream_handler)\n",
    "\n",
    "\n",
    "def log_in_history(func):\n",
    "    def wrapper(self, *args, **kwargs):\n",
    "        signature = inspect.signature(func)\n",
    "        keywords = {}\n",
    "        for i, (name, param) in enumerate(signature.parameters.items()):\n",
    "            if name == 'self':\n",
    "                continue\n",
    "            if param.kind == inspect.Parameter.POSITIONAL_OR_KEYWORD:\n",
    "                keywords[name] = args[i-1]\n",
    "            elif param.kind == inspect.Parameter.KEYWORD_ONLY:\n",
    "                if name in kwargs:\n",
    "                    keywords[name] = kwargs[name]\n",
    "                else:\n",
    "                    keywords[name] = param.default\n",
    "\n",
    "        # get docstring for this function:\n",
    "        docstring = inspect.getdoc(func)\n",
    "        \n",
    "        # extract \"API Calls\" section from docstring:\n",
    "        python_calls = api_docstring_to_python(\n",
    "            docstring, keywords\n",
    "        )\n",
    "        \n",
    "        # add trailing newline:\n",
    "        log.error(python_calls + '\\n')\n",
    "        \n",
    "        # don't forget to run the function, too!\n",
    "        func(self, *args, **kwargs)\n",
    "\n",
    "    # ensure func's docstring etc. is still attached to \n",
    "    # the wrapped method:\n",
    "    sig = inspect.signature(func)\n",
    "    wrapper.__signature__ = sig\n",
    "    wrapper.__doc__ = func.__doc__\n",
    "    wrapper.__annotations__ = func.__annotations__\n",
    "    wrapper.__name__ = func.__name__\n",
    "    \n",
    "    return wrapper\n",
    "\n",
    "\n",
    "def api_docstring_to_python(docstring, keywords):\n",
    "    api_calls = docstring.split(\n",
    "        'API Calls\\n---------\\n'\n",
    "    )[1]\n",
    "    \n",
    "    vars_to_format = re.findall(r'\\{(.*?)\\}', api_calls)\n",
    "    \n",
    "    define_vars = \"\"\n",
    "    for var in keywords:\n",
    "        if var not in vars_to_format:\n",
    "            define_vars += f\"{var} = {keywords[var]}\\n\"\n",
    "\n",
    "    return define_vars + api_calls.format(**keywords)\n",
    "\n",
    "class Demo:\n",
    "    \n",
    "    # learn how to use the `/` and `*` in call signatures\n",
    "    # to specify position only, positional or keyword, or \n",
    "    # keyword only arguments:\n",
    "    # https://stackoverflow.com/a/61719220/1340208\n",
    "\n",
    "    @log_in_history\n",
    "    def go(self, multiple, *, pi=3.1415926):\n",
    "        \"\"\"\n",
    "        Do this simple `go` function.\n",
    "        \n",
    "        API Calls\n",
    "        ---------\n",
    "        result = multiple * pi\n",
    "        \"\"\"\n",
    "        # the function's contents need not be\n",
    "        # strictly identical to the public API \n",
    "        # version that we offer in the log\n",
    "\n",
    "        return multiple * pi\n",
    "    \n",
    "    @log_in_history\n",
    "    def go_again(self, multiple, *, pi=3.1415926):\n",
    "        \"\"\"\n",
    "        Do this simple `go_again` function.\n",
    "        \n",
    "        API Calls\n",
    "        ---------\n",
    "        # some notes\n",
    "        pi = {pi}\n",
    "        \n",
    "        # some more notes\n",
    "        multiple = {multiple}\n",
    "        \n",
    "        result = multiple * pi\n",
    "        \"\"\"\n",
    "        # the function's contents need not be\n",
    "        # strictly identical to the public API \n",
    "        # version that we offer in the API Calls\n",
    "        # section of the docstring\n",
    "\n",
    "        return multiple * pi\n"
   ]
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     "text": [
      "multiple = 2\n",
      "pi = 3.1415926\n",
      "result = multiple * pi\n",
      "\n"
     ]
    }
   ],
   "source": [
    "demo = Demo()\n",
    "\n",
    "demo.go(2)"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "3ea08865-b2d8-48f7-9122-070b04dc20af",
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   "source": [
    "This docstring doesn't pre-format the values for `multiple` or `pi`, but the decorator automatically adds their definitions at the top.\n"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "d7b71b06-d96a-4e42-a687-86ddffc627ac",
   "metadata": {},
   "source": [
    "***"
   ]
  },
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   "cell_type": "code",
   "execution_count": 3,
   "id": "94353058-d8ba-4dd1-8ae1-fad1038ab722",
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     "name": "stdout",
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     "text": [
      "# some notes\n",
      "pi = 3.1415926\n",
      "\n",
      "# some more notes\n",
      "multiple = 2\n",
      "\n",
      "result = multiple * pi\n",
      "\n"
     ]
    }
   ],
   "source": [
    "demo = Demo()\n",
    "\n",
    "demo.go_again(2)"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "a26318b3-a8bf-42f2-ae5d-0bf544c278b3",
   "metadata": {},
   "source": [
    "This docstring *does* pre-format the values for `multiple` and `pi`, so they're not added to the top."
   ]
  },
  {
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   "execution_count": null,
   "id": "b256924b-1272-48c8-8657-12e8280bc504",
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   "source": []
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