.. _topics-telnetconsole:

==============
Telnet Console
==============

.. module:: scrapy.management.telnet
   :synopsis: The Telnet Console

Scrapy comes with a built-in telnet console for inspecting and controlling a
Scrapy running process. The telnet console is just a regular python shell
running inside the Scrapy process, so you can do literally anything from it.

The telnet console is a :ref:`built-in Scrapy extension
<topics-extensions-ref>` which comes enabled by default, but you can also
disable it if you want. For more information about the extension itself see
:ref:`topics-extensions-ref-telnetconsole`.

.. highlight:: none

How to access the telnet console
================================

The telnet console listens in the TCP port defined in the
:setting:`TELNETCONSOLE_PORT` setting, which defaults to ``6023``. To access
the console you need to type::

    telnet localhost 6023
    >>>
    
You need the telnet program which comes installed by default in Windows, and
most Linux distros.

Available aliases in the telnet console
=======================================

The telnet console is like a regular Python shell running inside the Scrapy
process, so you can do anything from it including imports, etc. 

However, the telnet console comes with some default aliases defined for
convenience:

    * ``engine``: the Scrapy engine object (``scrapy.core.engine.scrapyengine``)
    * ``manager``: the Scrapy manager object (``scrapy.core.manager.scrapymanager``)
    * ``extensions``: the extensions object (``scrapy.extension.extensions``)
    * ``stats``: the Scrapy stats object (``scrapy.stats.stats``)
    * ``settings``: the Scrapy settings object (``scrapy.conf.settings``)
    * ``p``: the pprint function (``pprint.pprint``)
    * ``prefs``: for memory debugging (see :ref:`topics-leaks`)
    * ``hpy``: for memory debugging (see :ref:`topics-leaks`)

Some example of using the telnet console
========================================

Here are some example tasks you can do with the telnet console:

View engine status
------------------

You can use the ``st()`` method of the Scrapy engine to quickly show its state
using the telnet console::

    telnet localhost 6023
    >>> engine.st()
    Execution engine status

    datetime.now()-self.start_time                  : 0:00:09.051588
    self.is_idle()                                  : False
    self.scheduler.is_idle()                        : False
    len(self.scheduler.pending_requests)            : 1
    self.downloader.is_idle()                       : False
    len(self.downloader.sites)                      : 1
    self.downloader.has_capacity()                  : True
    self.pipeline.is_idle()                         : False
    len(self.pipeline.domaininfo)                   : 1
    len(self._scraping)                             : 1

    example.com
      self.domain_is_idle(domain)                        : False
      self.closing.get(domain)                           : None
      self.scheduler.domain_has_pending_requests(domain) : True
      len(self.scheduler.pending_requests[domain])       : 97
      len(self.downloader.sites[domain].queue)           : 17
      len(self.downloader.sites[domain].active)          : 25
      len(self.downloader.sites[domain].transferring)    : 8
      self.downloader.sites[domain].closing              : False
      self.downloader.sites[domain].lastseen             : 2009-06-23 15:20:16.563675
      self.pipeline.domain_is_idle(domain)               : True
      len(self.pipeline.domaininfo[domain])              : 0
      len(self._scraping[domain])                        : 0


Pause, resume and stop Scrapy engine
------------------------------------

To pause::

    telnet localhost 6023
    >>> engine.pause()
    >>>

To resume::

    telnet localhost 6023
    >>> engine.unpause()
    >>>

To stop::

    telnet localhost 6023
    >>> engine.stop()
    Connection closed by foreign host.