simonw

How to recover lost Python source code if it's still resident in-memory

I screwed up using git ("git checkout --" on the wrong file) and managed to delete the code I had just written... but it was still running in a process in a docker container. Here's how I got it back, using https://pypi.python.org/pypi/pyrasite/ and https://pypi.python.org/pypi/uncompyle6

Attach a shell to the docker container

Install GDB (needed by pyrasite)

apt-get update && apt-get install gdb

Jach

import sys
import ctypes
pyint_p = ctypes.POINTER(ctypes.c_byte*sys.getsizeof(5))
five = ctypes.cast(id(5), pyint_p)
print(2 + 2 == 5) # False
five.contents[five.contents[:].index(5)] = 4
print(2 + 2 == 5) # True (must be sufficiently large values of 2 there...)