"""
.. module:: agi
:synopsis: More comprehensive traceback formatting for Python scripts.
Example
-------
To enable this module, do:
.. code-block:: python
import asterisk.agitb, asterisk.agi
asterisk.agitb.enable(display = False, logdir = '/var/log/asterisk/')
agi = asterisk.agi.AGI()
asterisk.agitb.enable(agi, False, '/var/log/asterisk')
at the top of your script. The optional arguments to enable() are:
* agi - the agi handle to write verbose messages to
* display - if true, tracebacks are displayed on the asterisk console
(used with the agi option)
* logdir - if set, tracebacks are written to files in this directory
* context - number of lines of source code to show for each stack frame
By default, tracebacks are displayed but not saved, and the context is 5 lines.
You may want to add a logdir if you call agitb.enable() before you have
an agi.AGI() handle.
Alternatively, if you have caught an exception and want agitb to display it
for you, call agitb.handler(). The optional argument to handler() is a
3-item tuple (etype, evalue, etb) just like the value of sys.exc_info().
If you do not pass anything to handler() it will use sys.exc_info().
This script was adapted from Ka-Ping Yee's cgitb.
Specification
-------------
"""
__author__ = 'Matthew Nicholson'
__version__ = '0.1.0'
import sys
__UNDEF__ = [] # a special sentinel object
[docs]def lookup(name, frame, locals):
"""Find the value for a given name in the given environment."""
if name in locals:
return 'local', locals[name]
if name in frame.f_globals:
return 'global', frame.f_globals[name]
if '__builtins__' in frame.f_globals:
builtins = frame.f_globals['__builtins__']
if isinstance(builtins, type({})):
if name in builtins:
return 'builtin', builtins[name]
else:
if hasattr(builtins, name):
return 'builtin', getattr(builtins, name)
return None, __UNDEF__
[docs]def scanvars(reader, frame, locals):
"""Scan one logical line of Python and look up values of variables used."""
import tokenize
import keyword
vars, lasttoken, parent, prefix, value = [], None, None, '', __UNDEF__
for ttype, token, start, end, line in tokenize.generate_tokens(reader):
if ttype == tokenize.NEWLINE:
break
if ttype == tokenize.NAME and token not in keyword.kwlist:
if lasttoken == '.':
if parent is not __UNDEF__:
value = getattr(parent, token, __UNDEF__)
vars.append((prefix + token, prefix, value))
else:
where, value = lookup(token, frame, locals)
vars.append((token, where, value))
elif token == '.':
prefix += lasttoken + '.'
parent = value
else:
parent, prefix = None, ''
lasttoken = token
return vars
[docs]def text(eparams, context=5):
"""Return a plain text document describing a given traceback."""
import os
import types
import time
import traceback
import linecache
import inspect
import pydoc
etype, evalue, etb = eparams
if isinstance(etype, types.ClassType):
etype = etype.__name__
pyver = 'Python ' + sys.version.split()[0] + ': ' + sys.executable
date = time.ctime(time.time())
head = "%s\n%s\n%s\n" % (str(etype), pyver, date) + '''
A problem occurred in a Python script. Here is the sequence of
function calls leading up to the error, in the order they occurred.
'''
frames = []
records = inspect.getinnerframes(etb, context)
for frame, file, lnum, func, lines, index in records:
file = file and os.path.abspath(file) or '?'
args, varargs, varkw, locals = inspect.getargvalues(frame)
call = ''
if func != '?':
call = 'in ' + func + \
inspect.formatargvalues(args, varargs, varkw, locals,
formatvalue=lambda value: '=' + pydoc.text.repr(value))
highlight = {}
def reader(lnum=[lnum]):
highlight[lnum[0]] = 1
try:
return linecache.getline(file, lnum[0])
finally:
lnum[0] += 1
vars = scanvars(reader, frame, locals)
rows = [' %s %s' % (file, call)]
if index is not None:
i = lnum - index
for line in lines:
num = '%5d ' % i
rows.append(num + line.rstrip())
i += 1
done, dump = {}, []
for name, where, value in vars:
if name in done:
continue
done[name] = 1
if value is not __UNDEF__:
if where == 'global':
name = 'global ' + name
elif where == 'local':
name = name
else:
name = where + name.split('.')[-1]
dump.append('%s = %s' % (name, pydoc.text.repr(value)))
else:
dump.append(name + ' undefined')
rows.append('\n'.join(dump))
frames.append('\n%s\n' % '\n'.join(rows))
exception = ['%s: %s' % (str(etype), str(evalue))]
if isinstance(evalue, types.InstanceType):
for name in dir(evalue):
value = pydoc.text.repr(getattr(evalue, name))
exception.append('\n%s%s = %s' % (" " * 4, name, value))
import traceback
return head + ''.join(frames) + ''.join(exception) + '''
The above is a description of an error in a Python program. Here is
the original traceback:
%s
''' % ''.join(traceback.format_exception(etype, evalue, etb))
[docs]class Hook:
"""A hook to replace sys.excepthook that shows tracebacks in HTML."""
def __init__(self, display=1, logdir=None, context=5, file=None,
agi=None):
self.display = display # send tracebacks to browser if true
self.logdir = logdir # log tracebacks to files if not None
self.context = context # number of source code lines per frame
self.file = file or sys.stderr # place to send the output
self.agi = agi
def __call__(self, etype, evalue, etb):
self.handle((etype, evalue, etb))
def handle(self, info=None):
info = info or sys.exc_info()
try:
doc = text(info, self.context)
except: # just in case something goes wrong
import traceback
doc = ''.join(traceback.format_exception(*info))
if self.display:
if self.agi: # print to agi
for line in doc.split('\n'):
self.agi.verbose(line, 4)
else:
self.file.write(doc + '\n')
if self.agi:
self.agi.verbose('A problem occured in a python script', 4)
else:
self.file.write('A problem occured in a python script\n')
if self.logdir is not None:
import os
import tempfile
(fd, path) = tempfile.mkstemp(suffix='.txt', dir=self.logdir)
try:
file = os.fdopen(fd, 'w')
file.write(doc)
file.close()
msg = '%s contains the description of this error.' % path
except:
msg = 'Tried to save traceback to %s, but failed.' % path
if self.agi:
self.agi.verbose(msg, 4)
else:
self.file.write(msg + '\n')
try:
self.file.flush()
except:
pass
handler = Hook().handle
[docs]def enable(agi=None, display=1, logdir=None, context=5):
"""Install an exception handler that formats tracebacks as HTML.
The optional argument 'display' can be set to 0 to suppress sending the
traceback to the browser, and 'logdir' can be set to a directory to cause
tracebacks to be written to files there."""
except_hook = Hook(display=display, logdir=logdir,
context=context, agi=agi)
sys.excepthook = except_hook
global handler
handler = except_hook.handle