IPython Documentation

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Module: core.magics.logging

Implementation of magic functions for IPython’s own logging.

1 Class

class IPython.core.magics.logging.LoggingMagics(shell)

Bases: IPython.core.magic.Magics

Magics related to all logging machinery.

logoff(parameter_s='')

Temporarily stop logging.

You must have previously started logging.

logon(parameter_s='')

Restart logging.

This function is for restarting logging which you’ve temporarily stopped with %logoff. For starting logging for the first time, you must use the %logstart function, which allows you to specify an optional log filename.

logstart(parameter_s='')

Start logging anywhere in a session.

%logstart [-o|-r|-t] [log_name [log_mode]]

If no name is given, it defaults to a file named ‘ipython_log.py’ in your current directory, in ‘rotate’ mode (see below).

‘%logstart name’ saves to file ‘name’ in ‘backup’ mode. It saves your history up to that point and then continues logging.

%logstart takes a second optional parameter: logging mode. This can be one of (note that the modes are given unquoted):

append: well, that says it.backup: rename (if exists) to name~ and start name.global: single logfile in your home dir, appended to.over : overwrite existing log.rotate: create rotating logs name.1~, name.2~, etc.

Options:

-o: log also IPython’s output. In this mode, all commands which generate an Out[NN] prompt are recorded to the logfile, right after their corresponding input line. The output lines are always prepended with a ‘#[Out]# ‘ marker, so that the log remains valid Python code.

Since this marker is always the same, filtering only the output from a log is very easy, using for example a simple awk call:

awk -F'#\[Out\]# ' '{if($2) {print $2}}' ipython_log.py

-r: log ‘raw’ input. Normally, IPython’s logs contain the processed input, so that user lines are logged in their final form, converted into valid Python. For example, %Exit is logged as _ip.magic(“Exit”). If the -r flag is given, all input is logged exactly as typed, with no transformations applied.

-t: put timestamps before each input line logged (these are put in comments).

logstate(parameter_s='')

Print the status of the logging system.

logstop(parameter_s='')

Fully stop logging and close log file.

In order to start logging again, a new %logstart call needs to be made, possibly (though not necessarily) with a new filename, mode and other options.