Yet another stack/session dumper utility

A "simple" library to help analyze issues post-mortem without a debugger attached.

Usage

Dumping the process state

You can use yasdu.dump() to dump the process state. Be careful:

Dumps like this can contain sensitive data, like passwords, authentication tokens etc. SHARE THEM WITH EXTREME CAUTION.
yasdu.dump will not overwrite files and will create filename.number files.

import yasdu
yasdu.dump('dump.json', 'Comment here')
# *** Created stack dump in 'dump.json' ***
# => 'dump.json'
# 'dump.json' is actual filename the dump was saved in

yasdu.dump('dump.json', 'Comment here')
# *** Created stack dump in 'dump.json.1' ***
# => 'dump.json.1'
# Since 'dump.json' already exists, the library picked 'dump.json.1'

Hooking exceptions.

The yasdu.hook() function will hook sys.excepthook and if there's an uncaught exception killing the program it will dump the process state into yasdu_autodump_[ISODATETIME].json See hook and crash example

Loading dumps

CLI tool

For the CLI IPython is recommended but not needed.

usage: yasdu [-h] -l FILE [-S] [-y]

optional arguments:
  -l FILE, --load FILE  Loads given file and starts a Python interpreter

  -S, --no-sources      Disables reading the sources from disk and showing them, useful if they have changed.
  -y                    Assume yes to all questions
  -h, --help            show this help message and exit

Example:

$ python examples/hook_and_crash.py
*** Created stack dump in 'yasdu_autodump.json' ***
Traceback (most recent call last):
  File "examples/hook_and_crash.py", line 13, in <module>
    happily_convert_some_values()
  File "examples/hook_and_crash.py", line 8, in happily_convert_some_values
    v2 = int('deadbeef')  # oh noes
ValueError: invalid literal for int() with base 10: 'deadbeef'

Let's inspect the automatic dump.

$ yasdu -l yasdu_autodump.json
Loading dump files can allow them to execute code. Do you still want to proceed? [y/N]y
Unpickled 9 objects...
Done loading data.


# exception traceback generated by the program ↓
This is an automatic dump it has been triggered by an exception:
Traceback (most recent call last):
  File "examples/hook_and_crash.py", line 13, in <module>
    happily_convert_some_values()
  File "examples/hook_and_crash.py", line 8, in happily_convert_some_values
    v2 = int('deadbeef')  # oh noes
ValueError: invalid literal for int() with base 10: 'deadbeef'

# stack data saved in the dump and sources loaded from disk
Available frames
  0. examples/hook_and_crash.py:13 happily_convert_some_values() <--  # we're here
  1. examples/hook_and_crash.py:8 v2 = int('deadbeef')  # oh noes
LoadedFrame object is available through the `_lframe` global variable

Using IPython for shell...
# [snip]

[hook_and_crash.py:13 (0)] In [1]: sources()
   import yasdu
   
   some_global_variable = 'testing123'
   
   
   def happily_convert_some_values():
       v1 = int('deadbeef', 16)
       v2 = int('deadbeef')  # oh noes
   
   
   if __name__ == '__main__':
       yasdu.hook()
->     happily_convert_some_values()

[hook_and_crash.py:13 (0)] In [2]: down()
Available frames
  0. examples/hook_and_crash.py:13 happily_convert_some_values()
  1. examples/hook_and_crash.py:8 v2 = int('deadbeef')  # oh noes <--

[hook_and_crash.py:13 (0)] In [3]: sources()
   import yasdu
   
   some_global_variable = 'testing123'
   
   
   def happily_convert_some_values():
       v1 = int('deadbeef', 16)
->     v2 = int('deadbeef')  # oh noes
   
   
   if __name__ == '__main__':
       yasdu.hook()
       happily_convert_some_values()

# variables are loaded from the dump
[hook_and_crash.py:13 (0)] In [4]: v1
Out[4]: 3735928559

[hook_and_crash.py:13 (0)] In [5]: some_global_variable
Out[5]: 'testing123'

Mm2PL / yasdu