{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Logging-Beispiele"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Erstellen einer Log-Datei"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {},
   "outputs": [
    {
     "name": "stderr",
     "output_type": "stream",
     "text": [
      "WARNING:root:This is a warning message\n",
      "CRITICAL:root:This is a critical message\n"
     ]
    }
   ],
   "source": [
    "import logging\n",
    "\n",
    "\n",
    "logging.warning(\"This is a warning message\")\n",
    "logging.critical(\"This is a critical message\")\n",
    "logging.debug(\"debug\")"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Logging-Ebenen\n",
    "\n",
    "Ebene | Beschreibung\n",
    ":-- | :--\n",
    "``CRITICAL`` | Das Programm wurde angehalten\n",
    "``ERROR`` | Ein schwerwiegender Fehler ist aufgetreten\n",
    "``WARNING`` | Ein Hinweis darauf, dass etwas Unerwartetes passiert ist (Standardstufe)\n",
    "``INFO`` | Bestätigung, dass die Dinge wie erwartet funktionieren.\n",
    "``DEBUG`` | Detaillierte Informationen, die in der Regel nur bei der Diagnose von Problemen von Interesse sind."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Setzen der Logging-Ebene"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [
    {
     "name": "stderr",
     "output_type": "stream",
     "text": [
      "ERROR:root:An error has happened!\n"
     ]
    }
   ],
   "source": [
    "import logging\n",
    "\n",
    "\n",
    "logging.basicConfig(filename=\"example.log\", filemode=\"w\", level=logging.INFO)\n",
    "\n",
    "logging.info(\"Informational message\")\n",
    "logging.error(\"An error has happened!\")"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Erstellen eines Logger-Objekts"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {},
   "outputs": [
    {
     "name": "stderr",
     "output_type": "stream",
     "text": [
      "ERROR:example:Error!\n",
      "Traceback (most recent call last):\n",
      "  File \"/var/folders/hk/s8m0bblj0g10hw885gld52mc0000gn/T/ipykernel_65477/2646645271.py\", line 9, in <module>\n",
      "    raise RuntimeError\n",
      "RuntimeError\n"
     ]
    }
   ],
   "source": [
    "import logging\n",
    "\n",
    "\n",
    "logging.basicConfig(filename=\"example.log\")\n",
    "logger = logging.getLogger(\"example\")\n",
    "logger.setLevel(logging.INFO)\n",
    "\n",
    "try:\n",
    "    raise RuntimeError\n",
    "except Exception:\n",
    "    logger.exception(\"Error!\")"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Ausnahmen (englisch *exceptions*) loggen"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {},
   "outputs": [
    {
     "name": "stderr",
     "output_type": "stream",
     "text": [
      "ERROR:example:You can’t do that!\n",
      "Traceback (most recent call last):\n",
      "  File \"/var/folders/hk/s8m0bblj0g10hw885gld52mc0000gn/T/ipykernel_65477/760044062.py\", line 2, in <module>\n",
      "    1 / 0\n",
      "    ~~^~~\n",
      "ZeroDivisionError: division by zero\n"
     ]
    }
   ],
   "source": [
    "try:\n",
    "    1 / 0\n",
    "except ZeroDivisionError:\n",
    "    logger.exception(\"You can’t do that!\")"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Logging-Handler\n",
    "\n",
    "### Handler-Typen\n",
    "\n",
    "Handler | Beschreibung\n",
    ":--- | :---\n",
    "`StreamHandler` | `stdout`, `stderr` oder dateiähnliche Objekte\n",
    "`FileHandler` | für das Schreiben auf die Festplatte\n",
    "`RotatingFileHandler` | unterstützt die Protokollrotation\n",
    "`TimedRotatingFileHandler` | unterstützt die Rotation von Protokolldateien auf der Festplatte in bestimmten Zeitabständen\n",
    "`SocketHandler` | sendet Logging-Ausgaben an einen Netzwerk-Socket\n",
    "`SMTPHandler` | unterstützt das Senden von Logging-Nachrichten an eine E-Mail-Adresse über SMTP\n",
    "\n",
    "<div class=\"alert alert-block alert-info\">\n",
    "\n",
    "**Siehe auch**\n",
    "\n",
    "Weitere Handler können gefunden werden unter [Logging handlers](https://docs.python.org/3/library/logging.handlers.html#module-logging.handlers).\n",
    "</div>"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### StreamHandler"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {},
   "outputs": [
    {
     "name": "stderr",
     "output_type": "stream",
     "text": [
      "This is an informational message\n",
      "INFO:stream_logger:This is an informational message\n"
     ]
    }
   ],
   "source": [
    "import logging\n",
    "\n",
    "\n",
    "logger = logging.getLogger(\"stream_logger\")\n",
    "logger.setLevel(logging.INFO)\n",
    "\n",
    "console = logging.StreamHandler()\n",
    "\n",
    "logger.addHandler(console)\n",
    "logger.info(\"This is an informational message\")"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### SMTPHandler"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {},
   "outputs": [
    {
     "name": "stderr",
     "output_type": "stream",
     "text": [
      "--- Logging error ---\n",
      "Traceback (most recent call last):\n",
      "  File \"/opt/homebrew/Cellar/python@3.11/3.11.4_1/Frameworks/Python.framework/Versions/3.11/lib/python3.11/logging/handlers.py\", line 1081, in emit\n",
      "    smtp = smtplib.SMTP(self.mailhost, port, timeout=self.timeout)\n",
      "           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^\n",
      "  File \"/opt/homebrew/Cellar/python@3.11/3.11.4_1/Frameworks/Python.framework/Versions/3.11/lib/python3.11/smtplib.py\", line 255, in __init__\n",
      "    (code, msg) = self.connect(host, port)\n",
      "                  ^^^^^^^^^^^^^^^^^^^^^^^^\n",
      "  File \"/opt/homebrew/Cellar/python@3.11/3.11.4_1/Frameworks/Python.framework/Versions/3.11/lib/python3.11/smtplib.py\", line 341, in connect\n",
      "    self.sock = self._get_socket(host, port, self.timeout)\n",
      "                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^\n",
      "  File \"/opt/homebrew/Cellar/python@3.11/3.11.4_1/Frameworks/Python.framework/Versions/3.11/lib/python3.11/smtplib.py\", line 312, in _get_socket\n",
      "    return socket.create_connection((host, port), timeout,\n",
      "           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^\n",
      "  File \"/opt/homebrew/Cellar/python@3.11/3.11.4_1/Frameworks/Python.framework/Versions/3.11/lib/python3.11/socket.py\", line 851, in create_connection\n",
      "    raise exceptions[0]\n",
      "  File \"/opt/homebrew/Cellar/python@3.11/3.11.4_1/Frameworks/Python.framework/Versions/3.11/lib/python3.11/socket.py\", line 836, in create_connection\n",
      "    sock.connect(sa)\n",
      "ConnectionRefusedError: [Errno 61] Connection refused\n",
      "Call stack:\n",
      "  File \"<frozen runpy>\", line 198, in _run_module_as_main\n",
      "  File \"<frozen runpy>\", line 88, in _run_code\n",
      "  File \"/Users/veit/.local/share/virtualenvs/python-311-6zxVKbDJ/lib/python3.11/site-packages/ipykernel_launcher.py\", line 17, in <module>\n",
      "    app.launch_new_instance()\n",
      "  File \"/Users/veit/.local/share/virtualenvs/python-311-6zxVKbDJ/lib/python3.11/site-packages/traitlets/config/application.py\", line 1043, in launch_instance\n",
      "    app.start()\n",
      "  File \"/Users/veit/.local/share/virtualenvs/python-311-6zxVKbDJ/lib/python3.11/site-packages/ipykernel/kernelapp.py\", line 736, in start\n",
      "    self.io_loop.start()\n",
      "  File \"/Users/veit/.local/share/virtualenvs/python-311-6zxVKbDJ/lib/python3.11/site-packages/tornado/platform/asyncio.py\", line 195, in start\n",
      "    self.asyncio_loop.run_forever()\n",
      "  File \"/opt/homebrew/Cellar/python@3.11/3.11.4_1/Frameworks/Python.framework/Versions/3.11/lib/python3.11/asyncio/base_events.py\", line 607, in run_forever\n",
      "    self._run_once()\n",
      "  File \"/opt/homebrew/Cellar/python@3.11/3.11.4_1/Frameworks/Python.framework/Versions/3.11/lib/python3.11/asyncio/base_events.py\", line 1922, in _run_once\n",
      "    handle._run()\n",
      "  File \"/opt/homebrew/Cellar/python@3.11/3.11.4_1/Frameworks/Python.framework/Versions/3.11/lib/python3.11/asyncio/events.py\", line 80, in _run\n",
      "    self._context.run(self._callback, *self._args)\n",
      "  File \"/Users/veit/.local/share/virtualenvs/python-311-6zxVKbDJ/lib/python3.11/site-packages/ipykernel/kernelbase.py\", line 516, in dispatch_queue\n",
      "    await self.process_one()\n",
      "  File \"/Users/veit/.local/share/virtualenvs/python-311-6zxVKbDJ/lib/python3.11/site-packages/ipykernel/kernelbase.py\", line 505, in process_one\n",
      "    await dispatch(*args)\n",
      "  File \"/Users/veit/.local/share/virtualenvs/python-311-6zxVKbDJ/lib/python3.11/site-packages/ipykernel/kernelbase.py\", line 412, in dispatch_shell\n",
      "    await result\n",
      "  File \"/Users/veit/.local/share/virtualenvs/python-311-6zxVKbDJ/lib/python3.11/site-packages/ipykernel/kernelbase.py\", line 740, in execute_request\n",
      "    reply_content = await reply_content\n",
      "  File \"/Users/veit/.local/share/virtualenvs/python-311-6zxVKbDJ/lib/python3.11/site-packages/ipykernel/ipkernel.py\", line 422, in do_execute\n",
      "    res = shell.run_cell(\n",
      "  File \"/Users/veit/.local/share/virtualenvs/python-311-6zxVKbDJ/lib/python3.11/site-packages/ipykernel/zmqshell.py\", line 546, in run_cell\n",
      "    return super().run_cell(*args, **kwargs)\n",
      "  File \"/Users/veit/.local/share/virtualenvs/python-311-6zxVKbDJ/lib/python3.11/site-packages/IPython/core/interactiveshell.py\", line 3009, in run_cell\n",
      "    result = self._run_cell(\n",
      "  File \"/Users/veit/.local/share/virtualenvs/python-311-6zxVKbDJ/lib/python3.11/site-packages/IPython/core/interactiveshell.py\", line 3064, in _run_cell\n",
      "    result = runner(coro)\n",
      "  File \"/Users/veit/.local/share/virtualenvs/python-311-6zxVKbDJ/lib/python3.11/site-packages/IPython/core/async_helpers.py\", line 129, in _pseudo_sync_runner\n",
      "    coro.send(None)\n",
      "  File \"/Users/veit/.local/share/virtualenvs/python-311-6zxVKbDJ/lib/python3.11/site-packages/IPython/core/interactiveshell.py\", line 3269, in run_cell_async\n",
      "    has_raised = await self.run_ast_nodes(code_ast.body, cell_name,\n",
      "  File \"/Users/veit/.local/share/virtualenvs/python-311-6zxVKbDJ/lib/python3.11/site-packages/IPython/core/interactiveshell.py\", line 3448, in run_ast_nodes\n",
      "    if await self.run_code(code, result, async_=asy):\n",
      "  File \"/Users/veit/.local/share/virtualenvs/python-311-6zxVKbDJ/lib/python3.11/site-packages/IPython/core/interactiveshell.py\", line 3508, in run_code\n",
      "    exec(code_obj, self.user_global_ns, self.user_ns)\n",
      "  File \"/var/folders/hk/s8m0bblj0g10hw885gld52mc0000gn/T/ipykernel_65477/3660210047.py\", line 14, in <module>\n",
      "    logger.info(\"This is an informational message\")\n",
      "Message: 'This is an informational message'\n",
      "Arguments: ()\n",
      "INFO:email_logger:This is an informational message\n"
     ]
    }
   ],
   "source": [
    "import logging\n",
    "import logging.handlers\n",
    "\n",
    "\n",
    "logger = logging.getLogger(\"email_logger\")\n",
    "logger.setLevel(logging.INFO)\n",
    "fh = logging.handlers.SMTPHandler(\n",
    "    \"localhost\",\n",
    "    fromaddr=\"python-log@localhost\",\n",
    "    toaddrs=[\"logs@cusy.io\"],\n",
    "    subject=\"Python log\",\n",
    ")\n",
    "logger.addHandler(fh)\n",
    "logger.info(\"This is an informational message\")"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Log-Formatierung\n",
    "\n",
    "Mit Formatierern könnt ihr den Log-Meldungen Formatierungen hinzufügen."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {},
   "outputs": [],
   "source": [
    "formatter = logging.Formatter(\"%(asctime)s - %(name)s - %(message)s\")"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Neben ``%(asctime)s``, ``%(name)s`` und ``%(message)s`` findet ihr noch weitere Attribute in [LogRecord attributes](https://docs.python.org/3/library/logging.html#logrecord-attributes)."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {},
   "outputs": [
    {
     "name": "stderr",
     "output_type": "stream",
     "text": [
      "This is an informational message\n",
      "2023-08-21 18:08:14,555 - stream_logger - This is an informational message\n",
      "INFO:stream_logger:This is an informational message\n"
     ]
    }
   ],
   "source": [
    "import logging\n",
    "\n",
    "\n",
    "logger = logging.getLogger(\"stream_logger\")\n",
    "logger.setLevel(logging.INFO)\n",
    "\n",
    "console = logging.StreamHandler()\n",
    "formatter = logging.Formatter(\"%(asctime)s - %(name)s - %(message)s\")\n",
    "console.setFormatter(formatter)\n",
    "\n",
    "logger.addHandler(console)\n",
    "logger.info(\"This is an informational message\")"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "<div class=\"alert alert-block alert-info\">\n",
    "\n",
    "**Bemerkung**\n",
    "\n",
    "Das Logging-Modul ist thread-sicher. Logging funktioniert jedoch möglicherweise nicht in asynchronen Kontexten. In solchen Fällen könnt ihr jedoch den [QueueHandler](https://docs.python.org/3/library/logging.handlers.html#queuehandler) verwenden.\n",
    "</div>"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "<div class=\"alert alert-block alert-info\">\n",
    "\n",
    "**Siehe auch**\n",
    "\n",
    "[Logging to a single file from multiple processes](https://docs.python.org/3/howto/logging-cookbook.html#logging-to-a-single-file-from-multiple-processes)\n",
    "</div>"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Logging an mehrere Handler"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "metadata": {},
   "outputs": [],
   "source": [
    "import logging\n",
    "\n",
    "\n",
    "def log(path, multipleLocs=False):\n",
    "    logger = logging.getLogger(\"Example_logger_%s\" % fname)\n",
    "    logger.setLevel(logging.INFO)\n",
    "    fh = logging.FileHandler(path)\n",
    "    formatter = logging.Formatter(\"%(asctime)s - %(name)s - %(message)s\")\n",
    "    fh.setFormatter(formatter)\n",
    "    logger.addHandler(fh)\n",
    "\n",
    "    if multipleLocs:\n",
    "        console = logging.StreamHandler()\n",
    "        console.setLevel(logging.INFO)\n",
    "        console.setFormatter(formatter)\n",
    "        logger.addHandler(console)\n",
    "\n",
    "    logger.info(\"This is an informational message\")\n",
    "    try:\n",
    "        1 / 0\n",
    "    except ZeroDivisionError:\n",
    "        logger.exception(\"You can’t do that!\")\n",
    "\n",
    "    logger.critical(\"This is a no-brainer!\")"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Logging konfigurieren\n",
    "\n",
    "<div class=\"alert alert-block alert-info\">\n",
    "\n",
    "**Siehe auch**\n",
    "\n",
    "[logging configuration](https://docs.python.org/3/howto/logging.html#configuring-logging)\n",
    "</div>"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### … in einer INI-Datei\n",
    "\n",
    "Im folgenden Beispiel wird die Datei `development.ini` in diesem Verzeichnis geladen:\n",
    "\n",
    "```ini\n",
    "[loggers]\n",
    "keys=root\n",
    "\n",
    "[handlers]\n",
    "keys=stream_handler\n",
    "\n",
    "[formatters]\n",
    "keys=formatter\n",
    "\n",
    "[logger_root]\n",
    "level=DEBUG\n",
    "handlers=stream_handler\n",
    "\n",
    "[handler_stream_handler]\n",
    "class=StreamHandler\n",
    "level=DEBUG\n",
    "formatter=formatter\n",
    "args=(sys.stderr,)\n",
    "\n",
    "[formatter_formatter]\n",
    "format=%(asctime)s %(name)-12s %(levelname)-8s %(message)s\n",
    "```"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 10,
   "metadata": {},
   "outputs": [],
   "source": [
    "import logging\n",
    "import logging.config\n",
    "\n",
    "from logging.config import fileConfig\n",
    "\n",
    "\n",
    "logging.config.fileConfig(\"development.ini\")\n",
    "logger = logging.getLogger(\"example\")\n",
    "\n",
    "logger.info(\"Program started\")\n",
    "logger.info(\"Done!\")"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "**Pro:**\n",
    "\n",
    "* Möglichkeit, die Konfiguration während des Betriebs zu aktualisieren, indem die Funktion `logging.config.listen()` verwendet wird um an einem Socket zu lauschen.\n",
    "* In verschiedenen Umgebungen können unterschiedliche Konfigurationen verwendet werden, also z.B. kann in der `development.ini` `DEBUG` als Log-Level angegeben werden, während in der `production.ini` `WARN` verwendet wird.\n",
    "\n",
    "**Con:**\n",
    "\n",
    "* Weniger Kontrolle z.B. gegenüber benutzerdefinierten Filtern oder Logger, die im Code konfiguriert sind."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### … in einer dictConfig"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 11,
   "metadata": {},
   "outputs": [],
   "source": [
    "import logging\n",
    "import logging.config\n",
    "\n",
    "\n",
    "dictLogConfig = {\n",
    "    \"version\": 1,\n",
    "    \"handlers\": {\n",
    "        \"fileHandler\": {\n",
    "            \"class\": \"logging.FileHandler\",\n",
    "            \"formatter\": \"exampleFormatter\",\n",
    "            \"filename\": \"dict_config.log\",\n",
    "        }\n",
    "    },\n",
    "    \"loggers\": {\n",
    "        \"exampleApp\": {\n",
    "            \"handlers\": [\"fileHandler\"],\n",
    "            \"level\": \"INFO\",\n",
    "        }\n",
    "    },\n",
    "    \"formatters\": {\n",
    "        \"exampleFormatter\": {\n",
    "            \"format\": \"%(asctime)s - %(name)s - %(levelname)s - %(message)s\"\n",
    "        }\n",
    "    },\n",
    "}"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 12,
   "metadata": {},
   "outputs": [
    {
     "name": "stderr",
     "output_type": "stream",
     "text": [
      "2023-08-21 18:08:14,573 exampleApp   INFO     Program started\n",
      "2023-08-21 18:08:14,574 exampleApp   INFO     Done!\n"
     ]
    }
   ],
   "source": [
    "logging.config.dictConfig(dictLogConfig)\n",
    "\n",
    "logger = logging.getLogger(\"exampleApp\")\n",
    "\n",
    "logger.info(\"Program started\")\n",
    "logger.info(\"Done!\")"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "**Pro:**\n",
    "\n",
    "* Aktualisieren während des Betriebs\n",
    "\n",
    "**Con:**\n",
    "\n",
    "* Weniger Kontrolle als beim Konfigurieren eines Loggers im Code"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### … direkt im Code"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 13,
   "metadata": {},
   "outputs": [],
   "source": [
    "logger = logging.getLogger()\n",
    "handler = logging.StreamHandler()\n",
    "formatter = logging.Formatter(\n",
    "    \"%(asctime)s %(name)-12s %(levelname)-8s %(message)s\"\n",
    ")\n",
    "handler.setFormatter(formatter)\n",
    "logger.addHandler(handler)\n",
    "logger.setLevel(logging.DEBUG)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## *Magic Commands*\n",
    "\n",
    "| Befehl         | Beschreibung                                                                              |\n",
    "| -------------- | ----------------------------------------------------------------------------------------- |\n",
    "| `%logstart`    | Startet das Logging irgendwo in einer Session                                             |\n",
    "|                | `%logstart [-o\\|-r\\|-t\\|-q] [log_name [log_mode]]`                                        |\n",
    "|                | Wenn kein Name angegeben wird, wird `ipython_log.py` im aktuellen Verzeichnis verwendet.  |\n",
    "|                | `log_mode` ist ein optionaler Parameter. Folgende Modi können angegeben werden:           |\n",
    "|                | * `append` hängt die Logging-Informationen am Ende einer vorhandenen Datei an             |\n",
    "|                | * `backup` benennt die vorhandene Datei um in `name~` und schreibt in `name`              |\n",
    "|                | * `global` hängt die Logging-Informationen am Ende einer vorhandenen Datei im             |\n",
    "|                | * `over` überschreibt eine existierende Log-Datei                                         |\n",
    "|                | * `rotate` erstellt rotierende Log-Dateien: `name.1~`, `name.2~`, etc.                    |\n",
    "|                | Optionen:                                                                                 |\n",
    "|                | * `-o` logt auch den Output von IPython                                                   |\n",
    "|                | * `-r` logt *raw* Output                                                                  |\n",
    "|                | * `-t` schreibt einen Zeitstempel vor jeden Logeintrag                                    |\n",
    "|                | * `-q` unterdrückt die Logging-Ausgabe                                                    |\n",
    "| `%logon`       | Neustart des Logging                                                                      |\n",
    "| `%logoff`      | Temporäres Beenden des Logging                                                            |\n",
    "\n",
    "**Pro:**\n",
    "\n",
    "* Vollständige Kontrolle über die Konfiguration\n",
    "\n",
    "**Con:**\n",
    "\n",
    "* Änderungen in der Konfiguration erfordern eine Änderung des Quellcodes"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Logs rotieren"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 14,
   "metadata": {},
   "outputs": [
    {
     "name": "stderr",
     "output_type": "stream",
     "text": [
      "2023-08-21 18:08:14,580 Rotating Log INFO     This is an example log line 0\n",
      "2023-08-21 18:08:14,580 Rotating Log INFO     This is an example log line 0\n",
      "2023-08-21 18:08:16,086 Rotating Log INFO     This is an example log line 1\n",
      "2023-08-21 18:08:16,086 Rotating Log INFO     This is an example log line 1\n",
      "2023-08-21 18:08:17,595 Rotating Log INFO     This is an example log line 2\n",
      "2023-08-21 18:08:17,595 Rotating Log INFO     This is an example log line 2\n",
      "2023-08-21 18:08:19,103 Rotating Log INFO     This is an example log line 3\n",
      "2023-08-21 18:08:19,103 Rotating Log INFO     This is an example log line 3\n",
      "2023-08-21 18:08:20,612 Rotating Log INFO     This is an example log line 4\n",
      "2023-08-21 18:08:20,612 Rotating Log INFO     This is an example log line 4\n",
      "2023-08-21 18:08:22,122 Rotating Log INFO     This is an example log line 5\n",
      "2023-08-21 18:08:22,122 Rotating Log INFO     This is an example log line 5\n",
      "2023-08-21 18:08:23,632 Rotating Log INFO     This is an example log line 6\n",
      "2023-08-21 18:08:23,632 Rotating Log INFO     This is an example log line 6\n",
      "2023-08-21 18:08:25,137 Rotating Log INFO     This is an example log line 7\n",
      "2023-08-21 18:08:25,137 Rotating Log INFO     This is an example log line 7\n",
      "2023-08-21 18:08:26,646 Rotating Log INFO     This is an example log line 8\n",
      "2023-08-21 18:08:26,646 Rotating Log INFO     This is an example log line 8\n",
      "2023-08-21 18:08:28,155 Rotating Log INFO     This is an example log line 9\n",
      "2023-08-21 18:08:28,155 Rotating Log INFO     This is an example log line 9\n"
     ]
    }
   ],
   "source": [
    "import logging\n",
    "import time\n",
    "\n",
    "from logging.handlers import RotatingFileHandler\n",
    "\n",
    "\n",
    "def create_rotating_log(path):\n",
    "    logger = logging.getLogger(\"Rotating Log\")\n",
    "    logger.setLevel(logging.INFO)\n",
    "\n",
    "    handler = RotatingFileHandler(path, maxBytes=20, backupCount=5)\n",
    "    logger.addHandler(handler)\n",
    "\n",
    "    for i in range(10):\n",
    "        logger.info(\"This is an example log line %s\" % i)\n",
    "        time.sleep(1.5)\n",
    "\n",
    "\n",
    "if __name__ == \"__main__\":\n",
    "    log_file = \"rotated.log\"\n",
    "    create_rotating_log(log_file)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Logs zeitgesteuert rotieren"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 15,
   "metadata": {},
   "outputs": [
    {
     "name": "stderr",
     "output_type": "stream",
     "text": [
      "2023-08-21 18:08:29,674 Rotating Log INFO     This is an example!\n",
      "2023-08-21 18:08:29,674 Rotating Log INFO     This is an example!\n",
      "2023-08-21 18:09:44,681 Rotating Log INFO     This is an example!\n",
      "2023-08-21 18:09:44,681 Rotating Log INFO     This is an example!\n",
      "2023-08-21 18:10:59,688 Rotating Log INFO     This is an example!\n",
      "2023-08-21 18:10:59,688 Rotating Log INFO     This is an example!\n",
      "2023-08-21 18:12:14,697 Rotating Log INFO     This is an example!\n",
      "2023-08-21 18:12:14,697 Rotating Log INFO     This is an example!\n",
      "2023-08-21 18:13:29,702 Rotating Log INFO     This is an example!\n",
      "2023-08-21 18:13:29,702 Rotating Log INFO     This is an example!\n",
      "2023-08-21 18:14:44,710 Rotating Log INFO     This is an example!\n",
      "2023-08-21 18:14:44,710 Rotating Log INFO     This is an example!\n"
     ]
    }
   ],
   "source": [
    "import logging\n",
    "import time\n",
    "\n",
    "from logging.handlers import TimedRotatingFileHandler\n",
    "\n",
    "\n",
    "def create_timed_rotating_log(path):\n",
    "    \"\"\"\"\"\"\n",
    "    logger = logging.getLogger(\"Rotating Log\")\n",
    "    logger.setLevel(logging.INFO)\n",
    "\n",
    "    handler = TimedRotatingFileHandler(\n",
    "        path, when=\"s\", interval=5, backupCount=5\n",
    "    )\n",
    "    logger.addHandler(handler)\n",
    "\n",
    "    for i in range(6):\n",
    "        logger.info(\"This is an example!\")\n",
    "        time.sleep(75)\n",
    "\n",
    "\n",
    "if __name__ == \"__main__\":\n",
    "    log_file = \"timed_rotation.log\"\n",
    "    create_timed_rotating_log(log_file)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Erstellen eines Logging-Dekorators\n",
    "\n",
    "<div class=\"alert alert-block alert-info\">\n",
    "\n",
    "**Siehe auch**\n",
    "\n",
    "[How to Create an Exception Logging Decorator](https://www.blog.pythonlibrary.org/2016/06/09/python-how-to-create-an-exception-logging-decorator/)\n",
    "</div>"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Einen Logging-Filter erstellen"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 16,
   "metadata": {},
   "outputs": [
    {
     "name": "stderr",
     "output_type": "stream",
     "text": [
      "2023-08-21 18:15:59,730 filter_example DEBUG    Message from bar\n",
      "2023-08-21 18:15:59,730 filter_example DEBUG    Message from bar\n"
     ]
    }
   ],
   "source": [
    "import logging\n",
    "import sys\n",
    "\n",
    "\n",
    "class ExampleFilter(logging.Filter):\n",
    "    def filter(self, record):\n",
    "        if record.funcName == \"foo\":\n",
    "            return False\n",
    "        return True\n",
    "\n",
    "\n",
    "logger = logging.getLogger(\"filter_example\")\n",
    "logger.addFilter(ExampleFilter())\n",
    "\n",
    "\n",
    "def foo():\n",
    "    \"\"\"\n",
    "    Ignore this function’s log messages\n",
    "    \"\"\"\n",
    "    logger.debug(\"Message from function foo\")\n",
    "\n",
    "\n",
    "def bar():\n",
    "    logger.debug(\"Message from bar\")\n",
    "\n",
    "\n",
    "if __name__ == \"__main__\":\n",
    "    logging.basicConfig(stream=sys.stderr, level=logging.DEBUG)\n",
    "    foo()\n",
    "    bar()"
   ]
  }
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