If tbvaccine provides (e.g.) a tbvaccine.pth file with contents similar to

import os; exec("if os.environ.get('TBVACCINE'):\n    <activation code>")

this would make it much easier to switch its functionality on and off without having to modify the "vaccined" code. You could even load the kwargs to TBVaccine from the environment variable, say as json: see https://github.com/anntzer/mplcursors/blob/master/setup.py for a self-contained example.

I'm having issues where I have very long variables (like a spreadsheet loaded in memory) and so when TBVaccine prints that, I lose everything else in my console buffer. Here is a quick and dirty hack to cap line length. It works by dropping ANSI sequences from long variable lines, and cap their length at 79*4 chars (approx. 4 output lines). A note is added to the line that there is more un-printed data.

(I can't figure out how to get decent lengths with normal string slicing on strings with ANSI codes embedded. For example, the output line | __annotations__ = {} clocks in with a length of 148 (!) due to ANSI control codes.)

The downside of dropping ANSI sequences like this is that the line won't be coloured....

Executing:

def x():
    raise Exception('hello')

def a(b):
    b()

a(x)

d:\...>python -m tbvaccine test_stack_trace.py
Error in sys.excepthook:
Traceback (most recent call last):
  File "d:\...\tbvaccine\tbv.py", line 193, in print_exception
    formatted = self._format_tb_string_with_locals(etype, value, tb)
  File "d:\...\tbvaccine\tbv.py", line 173, in _format_tb_string_with_locals
    max_length = max([len(x[0]) for x in var_tuples])
ValueError: max() arg is an empty sequence

Original exception was:
Traceback (most recent call last):
  File "C:\...\lib\runpy.py", line 193, in _run_module_as_main
    "__main__", mod_spec)
  File "C:\...\lib\runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "d:\...\tbvaccine\__main__.py", line 67, in <module>
    exec(code, variables, variables)
  File "test_stack_trace.py", line 7, in <module>
    a(x)
  File "test_stack_trace.py", line 5, in a
    b()
  File "test_stack_trace.py", line 2, in x
    raise Exception('hello')
Exception: hello

By mistake I just called python -m tbvaccine tox.ini.

The trace has no colors and it is longer then 100 lines, however calling python directly on a non python file causes only 4 lines for a single exception.

It would be great if tbvaccine could detect when a non python file is passed.

IOBase.stderr() has existed from at latest Python 2.7.4 and 3.1 (https://github.com/python/cpython/commit/4fa88fa0b), so sys.stderr.isatty() likely exists.

Hi, thanks for creating this great library!

I want to use this library in a kubernetes container where stderr is not a tty. It'll be convenient if we can do force-enabling by setting an environment variable.

It no effect when exception raised in flask request because the tracebacks are formatted by logging, the sys.excepthook is not called.

eg:

import tbvaccine
from flask import Flask

tbvaccine.add_hook(isolate=True)
app = Flask(__name__)


@app.route('/')
def index():
    return 1 / 0


if __name__ == '__main__':
    app.run()

the outputs:

 * Running on http://127.0.0.1:5000/ (Press CTRL+C to quit)
[2017-06-01 21:59:08,086] ERROR in app: Exception on / [GET]
Traceback (most recent call last):
  File "/home/guyskk/.local/share/virtualenvs/next_passport-OfYZSIo0/lib/python3.6/site-packages/flask/app.py", line 1982, in wsgi_app
    response = self.full_dispatch_request()
  File "/home/guyskk/.local/share/virtualenvs/next_passport-OfYZSIo0/lib/python3.6/site-packages/flask/app.py", line 1614, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/home/guyskk/.local/share/virtualenvs/next_passport-OfYZSIo0/lib/python3.6/site-packages/flask/app.py", line 1517, in handle_user_exception
    reraise(exc_type, exc_value, tb)
  File "/home/guyskk/.local/share/virtualenvs/next_passport-OfYZSIo0/lib/python3.6/site-packages/flask/_compat.py", line 33, in reraise
    raise value
  File "/home/guyskk/.local/share/virtualenvs/next_passport-OfYZSIo0/lib/python3.6/site-packages/flask/app.py", line 1612, in full_dispatch_request
    rv = self.dispatch_request()
  File "/home/guyskk/.local/share/virtualenvs/next_passport-OfYZSIo0/lib/python3.6/site-packages/flask/app.py", line 1598, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "app.py", line 10, in index
    return 1 / 0
ZeroDivisionError: division by zero
127.0.0.1 - - [01/Jun/2017 21:59:08] "GET / HTTP/1.1" 500 -

$ echo 1 | tbvaccine
Traceback (most recent call last):
  File "/mnt/storage/miniconda3/envs/CloudSML-Computational-Backend/bin/tbvaccine", line 11, in <module>
    sys.exit(main())
  File "/mnt/storage/miniconda3/envs/CloudSML-Computational-Backend/lib/python3.5/site-packages/tbvaccine/cli.py", line 29, in main
    output = tbv.process_line(line)
AttributeError: 'TBVaccine' object has no attribute 'process_line'

Hello there! Thank you very much for your work.

I'd like to get it to work in PyCharm, alas it's not trigerring at all there, but it works in consoles. Any advice here? :)

README says export TBVACCINE=1 hooks tbvaccine, so I expected export TBVACCINE=0 would not hook, but it did. I think the hook should be done only if TBVACCINE is exactly 1. (but that's a breaking change...)

Otherwise it was a relative link, and so was returning a GitHub 404 error page. --> https://github.com/skorokithakis/tbvaccine/blob/master/www.codeshelter.co

There is a specification for hyperlinks in terminals

https://gist.github.com/egmontkob/eb114294efbcd5adb1944c9f3cb5feda

It would be good if TBVacine could link to the python files mentioned.

Currently there isn't a way of linking to particular lines, but being able to open a file from the terminal is a nice improvement.

This may be worth gating behind config or envvar in case a terminal doesn't support it (though most should display nothing where the link will be anyway)

Without adding hook to my module (tgv):

Traceback (most recent call last): File "./tgv.py", line 618, in if name == "main": tgv() File "./tgv.py", line 426, in tgv 1/0 ZeroDivisionError: integer division or modulo by zero

real 0m2.904s user 0m2.344s sys 0m0.536s

With hook added

Traceback (most recent call last): File "./tgv.py", line 618, in if name == "main": tgv() <6 variables printed> File "./tgv.py", line 426, in tgv 1/0 <20 odd variables> ZeroDivisionError: integer division or modulo by zero

real 0m30.856s user 0m29.192s sys 0m1.572s

I'm guessing mostly the perf degradation is due to the high count of variables being printed. Anyway to control the output?

There's at least a couple problems with this working with ipython.

1. Exporting the env var seems to have no effect.
2. This brings the formatting of tbvaccine, and some things, but not the locals I added in the shell.

from tbvaccine import TBVaccine 
try:
    some_stuff()
except:
    print(TBVaccine().format_exc())

imagine this is styled:

Traceback (most recent call last):
  File "<ipython-input-2-6c94a79ed40f>", line 4, in <module>
>   some_stuff()
|     __annotations__ = {}
|     __builtins__    = <module 'builtins' (built-in)>
|     __cached__      = None
|     __doc__         = None
|     __file__        = [path to]/bin/ipython
|     __loader__      = <_frozen_importlib_external.SourceFileLoader object at 0x7f880a16fc88>
|     __name__        = __main__
|     __package__     = None
|     __spec__        = None
|     re              = <module 're' from '[path to]/lib/python3.6/re.py'>
|     start_ipython   = <function start_ipython at 0x7f88069a18c8>
|     sys             = <module 'sys' (built-in)>
NameError: name 'some_stuff' is not defined

3. This seems to not be any different from a normal exception in ipython. It looks identical either way.

import tbvaccine
tbvaccine.add_hook(isolate=False)

1 / 0

The same seems to hold for at least flask-shell-ipython, which is unsurprising.

Possibly out-of-scope: I have no idea really, but maybe whatever is needed to get this to work would also suffice for Jupyter as well. If we're lucky.

All local variables displayed on each stack frame lead to huge unreadable stack pretty fast. You could add a setting to display or not display them. Also, displaying functions and modules does not seem so helpful. You might get rid of them, or add a distinct setting to display them too.

It's not clear if tbvaccine supports Python 3's 'raise MyException from e' syntax.

Or at least the original exception is not being emitted in the tbvaccine output.

Here is the reproduction:

import tbvaccine
tbvaccine.add_hook(isolate=False)

import dask

def x(arg1=123):
    assert arg1 == 122, "qwe"

if __name__ == '__main__':
    dask.delayed(x)().compute()

The error:

  File "/tmp/env/lib/python3.5/site-packages/dask/async.py", line 272, in _execute_task
    return func(*args2)
  File "qq5.py", line 7, in x
    assert arg1 == 122, "qwe"
|     worker_id                = None
AssertionError: qwe

I don't understand at all where worker_id came from.

Running Dask Distributed, I see the output, which reports things which don't exist in that scope at all...

import tbvaccine
tbvaccine.add_hook(isolate=False)

import dask
import dask.distributed


def x(arg1=123):
    assert arg1 == 122, "qwe"

if __name__ == '__main__':
    client = dask.distributed.Client()
    dask.delayed(x)().compute(get=client.get)

  File "/tmp/env/lib/python3.5/site-packages/dask/base.py", line 203, in compute
    results = get(dsk, keys, **kwargs)
|     x = b'\x80\x04\x95\xa1\x00\x00\x00\x00\x00\x00\x00\x8c\x16tblib.pickling_support\x94\x8c\x12unpickle_traceback\x94\x93\x94\x8c\x05tblib\x94\x8c\x05Frame\x94\x93\x94)\x81\x94}\x94(\x8c\x06f_code\x94h\x03\x8c\x04Code\x94\x93\x94)\x81\x94}\x94(\x8c\x07co_name\x94\x8c\x01x\x94\x8c\x0bco_filename\x94\x8c\x06qq4.py\x94ub\x8c\tf_globals\x94}\x94ubK\tN\x87\x94R\x94.'
  File "/tmp/env/lib/python3.5/site-packages/distributed/client.py", line 1590, in get
    resources=resources)
|     ret       = <tblib.Traceback object at 0x7f95aeadfcf8>
|     tb_frame  = <tblib.Frame object at 0x7f95aeadf908>
|     tb_lineno = 9
|     tb_next   = None
  File "/tmp/env/lib/python3.5/site-packages/distributed/utils.py", line 223, in sync
    six.reraise(*error[0])
|     code   = <code object x at 0x7f95aeb33270, file "qq4.py", line 9>
|     f_code = <tblib.Code object at 0x7f95aeadf9b0>
|     self   = <tblib.Traceback object at 0x7f95aeadfcf8>
|     tb     = <traceback object at 0x7f95aeaeb148>
  File "/tmp/env/lib/python3.5/site-packages/six.py", line 686, in reraise
    raise value
AssertionError: qwe

The direct call to x() produces a sane output, so it should be some magic involved with Dask. Better-Exceptions module just hangs in this situation, so TBVaccine is better in this respect, but it is still completely misleading and unhelpful.