Source code for spack.util.debug

# Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
# Spack Project Developers. See the top-level COPYRIGHT file for details.
#
# SPDX-License-Identifier: (Apache-2.0 OR MIT)

"""Debug signal handler: prints a stack trace and enters interpreter.

``register_interrupt_handler()`` enables a ctrl-C handler that prints
a stack trace and drops the user into an interpreter.

"""
import code
import os
import pdb
import signal
import sys
import traceback


[docs]def debug_handler(sig, frame): """Interrupt running process, and provide a python prompt for interactive debugging.""" d = {'_frame': frame} # Allow access to frame object. d.update(frame.f_globals) # Unless shadowed by global d.update(frame.f_locals) i = code.InteractiveConsole(d) message = "Signal received : entering python shell.\nTraceback:\n" message += ''.join(traceback.format_stack(frame)) i.interact(message) os._exit(1) # Use os._exit to avoid test harness.
[docs]def register_interrupt_handler(): """Print traceback and enter an interpreter on Ctrl-C""" signal.signal(signal.SIGINT, debug_handler)
# Subclass of the debugger to keep readline working. See # https://stackoverflow.com/questions/4716533/how-to-attach-debugger-to-a-python-subproccess/23654936
[docs]class ForkablePdb(pdb.Pdb): """ This class allows the python debugger to follow forked processes and can set tracepoints allowing the Python Debugger Pdb to be used from a python multiprocessing child process. This is used the same way one would normally use Pdb, simply import this class and use as a drop in for Pdb, although the syntax here is slightly different, requiring the instantiton of this class, i.e. ForkablePdb().set_trace(). This should be used when attempting to call a debugger from a child process spawned by the python multiprocessing such as during the run of Spack.install, or any where else Spack spawns a child process. """ _original_stdin_fd = sys.stdin.fileno() _original_stdin = None def __init__(self, stdout_fd=None, stderr_fd=None): pdb.Pdb.__init__(self, nosigint=True) self._stdout_fd = stdout_fd self._stderr_fd = stderr_fd def _cmdloop(self): current_stdin = sys.stdin try: if not self._original_stdin: self._original_stdin = os.fdopen(self._original_stdin_fd) sys.stdin = self._original_stdin if self._stdout_fd is not None: os.dup2(self._stdout_fd, sys.stdout.fileno()) os.dup2(self._stdout_fd, self.stdout.fileno()) if self._stderr_fd is not None: os.dup2(self._stderr_fd, sys.stderr.fileno()) self.cmdloop() finally: sys.stdin = current_stdin