tornado.log — Logging support · Tornado 4.3官方文档

### Navigation - [index](# "General Index") - [modules](# "Python Module Index") | - [next](# "tornado.options — Command-line parsing") | - [previous](# "tornado.autoreload — Automatically detect code changes in development") | - [Tornado 4.4.dev1 documentation](#) » - [Utilities](#) » # `tornado.log` — Logging support Logging support for Tornado. Tornado uses three logger streams: - `tornado.access`: Per-request logging for Tornado's HTTP servers (andpotentially other servers in the future) - `tornado.application`: Logging of errors from application code (i.e.uncaught exceptions from callbacks) - `tornado.general`: General-purpose logging, including any errorsor warnings from Tornado itself. These streams may be configured independently using the standard library's[`logging`](https://docs.python.org/3.4/library/logging.html#module-logging "(in Python v3.4)") [https://docs.python.org/3.4/library/logging.html#module-logging] module. For example, you may wish to send `tornado.access` logsto a separate file for analysis. *class *`tornado.log.``LogFormatter`(*color=True*, *fmt='%(color)s[%(levelname)1.1s %(asctime)s %(module)s:%(lineno)d]%(end_color)s %(message)s'*, *datefmt='%y%m%d %H:%M:%S'*, *colors={40: 1*, *10: 4*, *20: 2*, *30: 3}*)[[source]](#) Log formatter used in Tornado. Key features of this formatter are: - Color support when logging to a terminal that supports it. - Timestamps on every log line. - Robust against str/bytes encoding problems. This formatter is enabled automatically by[`tornado.options.parse_command_line`](# "tornado.options.parse_command_line") (unless `--logging=none` isused). <table class="docutils field-list" frame="void" rules="none"><col class="field-name"/><col class="field-body"/><tbody valign="top"><tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><ul class="first last simple"><li>color (<a class="reference external" href="https://docs.python.org/3.4/library/functions.html#bool" title="(in Python v3.4)">bool</a> [https://docs.python.org/3.4/library/functions.html#bool]) – Enables color support.</li><li>fmt (<a class="reference external" href="https://docs.python.org/3.4/library/string.html#module-string" title="(in Python v3.4)">string</a> [https://docs.python.org/3.4/library/string.html#module-string]) – Log message format.It will be applied to the attributes dict of log records. Thetext between <code class="docutils literal">%(color)s</code> and <code class="docutils literal">%(end_color)s</code> will be coloreddepending on the level if color support is on.</li><li>colors (<a class="reference external" href="https://docs.python.org/3.4/library/stdtypes.html#dict" title="(in Python v3.4)">dict</a> [https://docs.python.org/3.4/library/stdtypes.html#dict]) – color mappings from logging level to terminal colorcode</li><li>datefmt (<a class="reference external" href="https://docs.python.org/3.4/library/string.html#module-string" title="(in Python v3.4)">string</a> [https://docs.python.org/3.4/library/string.html#module-string]) – Datetime format.Used for formatting <code class="docutils literal">(asctime)</code> placeholder in <code class="docutils literal">prefix_fmt</code>.</li></ul></td></tr></tbody></table> Changed in version 3.2: Added `fmt` and `datefmt` arguments. `tornado.log.``enable_pretty_logging`(*options=None*, *logger=None*)[[source]](#) Turns on formatted logging output as configured. This is called automatically by [`tornado.options.parse_command_line`](# "tornado.options.parse_command_line")and [`tornado.options.parse_config_file`](# "tornado.options.parse_config_file"). `tornado.log.``define_logging_options`(*options=None*)[[source]](#) Add logging-related flags to `options`. These options are present automatically on the default options instance;this method is only necessary if you have created your own [`OptionParser`](# "tornado.options.OptionParser"). New in version 4.2: This function existed in prior versions but was broken and undocumented until 4.2. © Copyright 2009-2016, The Tornado Authors. Created using [Sphinx](http://sphinx-doc.org/) 1.3.5.