from __future__ import absolute_import
import ast
import os
import pdb
import sys
from colorama import AnsiToWin32
from colorama import Back
from colorama import Fore
from colorama import Style
from fields import Fields
from six import string_types
DEFAULT_MIN_FILENAME_ALIGNMENT = 40
NO_COLORS = {
'reset': '',
'filename': '',
'colon': '',
'lineno': '',
'kind': '',
'continuation': '',
'return': '',
'exception': '',
'detail': '',
'vars': '',
'vars-name': '',
'call': '',
'line': '',
'internal-failure': '',
'internal-detail': '',
'source-failure': '',
'source-detail': '',
}
EVENT_COLORS = {
'reset': Style.RESET_ALL,
'filename': '',
'colon': Fore.BLACK + Style.BRIGHT,
'lineno': Style.RESET_ALL,
'kind': Fore.CYAN,
'continuation': Fore.BLUE,
'return': Style.BRIGHT + Fore.GREEN,
'exception': Style.BRIGHT + Fore.RED,
'detail': Style.NORMAL,
'vars': Style.RESET_ALL + Fore.MAGENTA,
'vars-name': Style.BRIGHT,
'internal-failure': Back.RED + Style.BRIGHT + Fore.RED,
'internal-detail': Fore.WHITE,
'source-failure': Style.BRIGHT + Back.YELLOW + Fore.YELLOW,
'source-detail': Fore.WHITE,
}
CODE_COLORS = {
'call': Fore.RESET + Style.BRIGHT,
'line': Fore.RESET,
'return': Fore.YELLOW,
'exception': Fore.RED,
}
class Action(object):
def __call__(self, event):
raise NotImplementedError()
[docs]class Debugger(Fields.klass.kwargs, Action):
"""
An action that starts ``pdb``.
"""
def __init__(self, klass=pdb.Pdb, **kwargs):
self.klass = klass
self.kwargs = kwargs
[docs] def __call__(self, event):
"""
Runs a ``pdb.set_trace`` at the matching frame.
"""
self.klass(**self.kwargs).set_trace(event.frame)
class ColorStreamAction(Action):
_stream_cache = {}
_stream = None
_tty = None
default_stream = sys.stderr
force_colors = False
@property
def stream(self):
return self._stream
@stream.setter
def stream(self, value):
if isinstance(value, string_types):
if value in self._stream_cache:
value = self._stream_cache[value]
else:
value = self._stream_cache[value] = open(value, 'a', buffering=0)
isatty = getattr(value, 'isatty', None)
if self.force_colors or (isatty and isatty() and os.name != 'java'):
self._stream = AnsiToWin32(value)
self._tty = True
self.event_colors = EVENT_COLORS
self.code_colors = CODE_COLORS
else:
self._tty = False
self._stream = value
self.event_colors = NO_COLORS
self.code_colors = NO_COLORS
def _safe_repr(self, obj):
try:
return repr(obj)
except Exception as exc:
return "{internal-failure}!!! FAILED REPR: {internal-detail}{!r}".format(exc, **self.event_colors)
[docs]class CodePrinter(Fields.stream.filename_alignment, ColorStreamAction):
"""
An action that just prints the code being executed.
Args:
stream (file-like): Stream to write to. Default: ``sys.stderr``.
filename_alignment (int): Default size for the filename column (files are right-aligned). Default: ``40``.
"""
def __init__(self,
stream=ColorStreamAction.default_stream, force_colors=False,
filename_alignment=DEFAULT_MIN_FILENAME_ALIGNMENT):
self.stream = stream
self.force_colors = force_colors
self.filename_alignment = max(5, filename_alignment)
def _safe_source(self, event):
try:
lines = event._raw_fullsource.rstrip().splitlines()
if lines:
return lines
else:
return "{source-failure}??? NO SOURCE: {source-detail}" \
"Source code string for module {!r} is empty.".format(event.module, **self.event_colors),
return lines
except Exception as exc:
return "{source-failure}??? NO SOURCE: {source-detail}{!r}".format(exc, **self.event_colors),
[docs] def __call__(self, event, sep=os.path.sep, join=os.path.join):
"""
Handle event and print filename, line number and source code. If event.kind is a `return` or `exception` also
prints values.
"""
filename = event.filename or "<???>"
if len(filename) > self.filename_alignment:
filename = '[...]{}'.format(filename[5 - self.filename_alignment:])
# context = event.tracer
# alignment = context.filename_alignment = max(
# getattr(context, 'filename_alignment', 5),
# len(filename)
# )
lines = self._safe_source(event)
self.stream.write("{filename}{:>{align}}{colon}:{lineno}{:<5} {kind}{:9} {code}{}{reset}\n".format(
filename,
event.lineno,
event.kind,
lines[0],
align=self.filename_alignment,
code=self.code_colors[event.kind],
**self.event_colors
))
for line in lines[1:]:
self.stream.write("{:>{align}} {kind}{:9} {code}{}{reset}\n".format(
"",
r" |",
line,
align=self.filename_alignment,
code=self.code_colors[event.kind],
**self.event_colors
))
if event.kind in ('return', 'exception'):
self.stream.write("{:>{align}} {continuation}{:9} {color}{} value: {detail}{}{reset}\n".format(
"",
"...",
event.kind,
self._safe_repr(event.arg),
align=self.filename_alignment,
color=self.event_colors[event.kind],
**self.event_colors
))
[docs]class VarsPrinter(Fields.names.globals.stream.filename_alignment, ColorStreamAction):
"""
An action that prints local variables and optionally global variables visible from the current executing frame.
Args:
*names (strings): Names to evaluate. Expressions can be used (will only try to evaluate if all the variables are
present on the frame.
stream (file-like): Stream to write to. Default: ``sys.stderr``.
filename_alignment (int): Default size for the filename column (files are right-aligned). Default: ``40``.
globals (bool): Allow access to globals. Default: ``False`` (only looks at locals).
"""
def __init__(self, *names, **options):
if not names:
raise TypeError("Must give at least one name/expression.")
self.stream = options.pop('stream', self.default_stream)
self.force_colors = options.pop('force_colors', False)
self.filename_alignment = max(5, options.pop('filename_alignment', DEFAULT_MIN_FILENAME_ALIGNMENT))
self.names = {
name: set(self._iter_symbols(name))
for name in names
}
self.globals = options.pop('globals', False)
@staticmethod
def _iter_symbols(code):
"""
Iterate all the variable names in the given expression.
Example:
* ``self.foobar`` yields ``self``
* ``self[foobar]`` yields `self`` and ``foobar``
"""
for node in ast.walk(ast.parse(code)):
if isinstance(node, ast.Name):
yield node.id
def _safe_eval(self, code, event):
"""
Try to evaluate the given code on the given frame. If failure occurs, returns some ugly string with exception.
"""
try:
return eval(code, event.globals if self.globals else {}, event.locals)
except Exception as exc:
return "{internal-failure}FAILED EVAL: {internal-detail}{!r}".format(exc, **self.event_colors)
[docs] def __call__(self, event):
"""
Handle event and print the specified variables.
"""
first = True
frame_symbols = set(event.locals)
if self.globals:
frame_symbols |= set(event.globals)
for code, symbols in self.names.items():
try:
obj = eval(code, event.globals if self.globals else {}, event.locals)
except AttributeError:
continue
except Exception as exc:
printout = "{internal-failure}FAILED EVAL: {internal-detail}{!r}".format(exc, **self.event_colors)
else:
printout = self._safe_repr(obj)
if frame_symbols >= symbols:
self.stream.write("{:>{align}} {vars}{:9} {vars-name}{} {vars}=> {reset}{}{reset}\n".format(
"",
"vars" if first else "...",
code,
printout,
align=self.filename_alignment,
**self.event_colors
))
first = False
