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Make event triggering robust to (un)registration....
Make event triggering robust to (un)registration. Event callbacks can register or unregister new callbacks for the same event while executing, and the previous triggering implementation allowed for event callbacks to be inadvertently skipped. The fix is to make a copy of the list of callbacks before executing any of them. With this change, the resulting semantics are simple: any callbacks registered before triggering are executed, and any new callbacks registered are only visible at the next triggering of the event. Note that this could potentially break existing callers who expected newly-appended callbacks were immediately executed. Fixes #9447. Originally based on a patch by @marksandler2.

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logger.py
221 lines | 7.9 KiB | text/x-python | PythonLexer
"""Logger class for IPython's logging facilities.
"""
from __future__ import print_function
#*****************************************************************************
# Copyright (C) 2001 Janko Hauser <jhauser@zscout.de> and
# Copyright (C) 2001-2006 Fernando Perez <fperez@colorado.edu>
#
# Distributed under the terms of the BSD License. The full license is in
# the file COPYING, distributed as part of this software.
#*****************************************************************************
#****************************************************************************
# Modules and globals
# Python standard modules
import glob
import io
import os
import time
from IPython.utils.py3compat import str_to_unicode
#****************************************************************************
# FIXME: This class isn't a mixin anymore, but it still needs attributes from
# ipython and does input cache management. Finish cleanup later...
class Logger(object):
"""A Logfile class with different policies for file creation"""
def __init__(self, home_dir, logfname='Logger.log', loghead=u'',
logmode='over'):
# this is the full ipython instance, we need some attributes from it
# which won't exist until later. What a mess, clean up later...
self.home_dir = home_dir
self.logfname = logfname
self.loghead = loghead
self.logmode = logmode
self.logfile = None
# Whether to log raw or processed input
self.log_raw_input = False
# whether to also log output
self.log_output = False
# whether to put timestamps before each log entry
self.timestamp = False
# activity control flags
self.log_active = False
# logmode is a validated property
def _set_mode(self,mode):
if mode not in ['append','backup','global','over','rotate']:
raise ValueError('invalid log mode %s given' % mode)
self._logmode = mode
def _get_mode(self):
return self._logmode
logmode = property(_get_mode,_set_mode)
def logstart(self, logfname=None, loghead=None, logmode=None,
log_output=False, timestamp=False, log_raw_input=False):
"""Generate a new log-file with a default header.
Raises RuntimeError if the log has already been started"""
if self.logfile is not None:
raise RuntimeError('Log file is already active: %s' %
self.logfname)
# The parameters can override constructor defaults
if logfname is not None: self.logfname = logfname
if loghead is not None: self.loghead = loghead
if logmode is not None: self.logmode = logmode
# Parameters not part of the constructor
self.timestamp = timestamp
self.log_output = log_output
self.log_raw_input = log_raw_input
# init depending on the log mode requested
isfile = os.path.isfile
logmode = self.logmode
if logmode == 'append':
self.logfile = io.open(self.logfname, 'a', encoding='utf-8')
elif logmode == 'backup':
if isfile(self.logfname):
backup_logname = self.logfname+'~'
# Manually remove any old backup, since os.rename may fail
# under Windows.
if isfile(backup_logname):
os.remove(backup_logname)
os.rename(self.logfname,backup_logname)
self.logfile = io.open(self.logfname, 'w', encoding='utf-8')
elif logmode == 'global':
self.logfname = os.path.join(self.home_dir,self.logfname)
self.logfile = io.open(self.logfname, 'a', encoding='utf-8')
elif logmode == 'over':
if isfile(self.logfname):
os.remove(self.logfname)
self.logfile = io.open(self.logfname,'w', encoding='utf-8')
elif logmode == 'rotate':
if isfile(self.logfname):
if isfile(self.logfname+'.001~'):
old = glob.glob(self.logfname+'.*~')
old.sort()
old.reverse()
for f in old:
root, ext = os.path.splitext(f)
num = int(ext[1:-1])+1
os.rename(f, root+'.'+repr(num).zfill(3)+'~')
os.rename(self.logfname, self.logfname+'.001~')
self.logfile = io.open(self.logfname, 'w', encoding='utf-8')
if logmode != 'append':
self.logfile.write(self.loghead)
self.logfile.flush()
self.log_active = True
def switch_log(self,val):
"""Switch logging on/off. val should be ONLY a boolean."""
if val not in [False,True,0,1]:
raise ValueError('Call switch_log ONLY with a boolean argument, '
'not with: %s' % val)
label = {0:'OFF',1:'ON',False:'OFF',True:'ON'}
if self.logfile is None:
print("""
Logging hasn't been started yet (use logstart for that).
%logon/%logoff are for temporarily starting and stopping logging for a logfile
which already exists. But you must first start the logging process with
%logstart (optionally giving a logfile name).""")
else:
if self.log_active == val:
print('Logging is already',label[val])
else:
print('Switching logging',label[val])
self.log_active = not self.log_active
self.log_active_out = self.log_active
def logstate(self):
"""Print a status message about the logger."""
if self.logfile is None:
print('Logging has not been activated.')
else:
state = self.log_active and 'active' or 'temporarily suspended'
print('Filename :', self.logfname)
print('Mode :', self.logmode)
print('Output logging :', self.log_output)
print('Raw input log :', self.log_raw_input)
print('Timestamping :', self.timestamp)
print('State :', state)
def log(self, line_mod, line_ori):
"""Write the sources to a log.
Inputs:
- line_mod: possibly modified input, such as the transformations made
by input prefilters or input handlers of various kinds. This should
always be valid Python.
- line_ori: unmodified input line from the user. This is not
necessarily valid Python.
"""
# Write the log line, but decide which one according to the
# log_raw_input flag, set when the log is started.
if self.log_raw_input:
self.log_write(line_ori)
else:
self.log_write(line_mod)
def log_write(self, data, kind='input'):
"""Write data to the log file, if active"""
#print 'data: %r' % data # dbg
if self.log_active and data:
write = self.logfile.write
if kind=='input':
if self.timestamp:
write(str_to_unicode(time.strftime('# %a, %d %b %Y %H:%M:%S\n',
time.localtime())))
write(data)
elif kind=='output' and self.log_output:
odata = u'\n'.join([u'#[Out]# %s' % s
for s in data.splitlines()])
write(u'%s\n' % odata)
self.logfile.flush()
def logstop(self):
"""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."""
if self.logfile is not None:
self.logfile.close()
self.logfile = None
else:
print("Logging hadn't been started.")
self.log_active = False
# For backwards compatibility, in case anyone was using this.
close_log = logstop