Source code for camcops_server.cc_modules.cc_debug

#!/usr/bin/env python

"""
camcops_server/cc_modules/cc_debug.py

===============================================================================

    Copyright (C) 2012-2020 Rudolf Cardinal (rudolf@pobox.com).

    This file is part of CamCOPS.

    CamCOPS is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    CamCOPS is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with CamCOPS. If not, see <https://www.gnu.org/licenses/>.

===============================================================================

**Debugging utilities**

"""

import cProfile
# import trace
from types import FrameType
from typing import Any, Callable, Set, Union

TraceFuncType = Callable[[FrameType, str, Any], Union[Callable, None]]
# ... returns a trace function (but we can't make the type definition
# recursive) or None.


# https://stackoverflow.com/questions/5375624/a-decorator-that-profiles-a-method-call-and-logs-the-profiling-result  # noqa
[docs]def profile(func): """ Decorator to generate profiler output for slow code from camcops_server.cc_debug import profile. Add @profile to the function you want to profile. Will generate a file called <function name>.profile. Can be visualised with e.g. SnakeViz (pip install snakeviz) """ def wrapper(*args, **kwargs): datafn = func.__name__ + ".profile" prof = cProfile.Profile() retval = prof.runcall(func, *args, **kwargs) prof.dump_stats(datafn) return retval return wrapper
# noinspection PyUnusedLocal
[docs]def trace_calls(frame: FrameType, event: str, arg: Any) \ -> Union[TraceFuncType, None]: """ A function that can be used as an argument to ``sys.settrace``. It prints details of every function called (filename, line number, function name). """ # https://pymotw.com/2/sys/tracing.html # https://docs.python.org/3/library/sys.html#sys.settrace # Function calls only if event != "call": return co = frame.f_code filename = co.co_filename func_name = co.co_name line_no = frame.f_lineno print(f"- Call to {filename}:{line_no}:{func_name}")
[docs]def makefunc_trace_unique_calls(file_only: bool = False) -> TraceFuncType: """ Creates a function that you can use as an argument to ``sys.settrace()``. When you execute a trace, it shows only new call to each function. Args: file_only: Shows files called only, not functions with line numbers. """ called = set() # type: Set[str] # noinspection PyUnusedLocal def _trace_calls(frame: FrameType, event: str, arg: Any) \ -> Union[TraceFuncType, None]: nonlocal called if event != "call": return co = frame.f_code filename = co.co_filename if file_only: signature = filename else: func_name = co.co_name line_no = frame.f_lineno signature = f"{filename}:{line_no}:{func_name}" if signature not in called: print(f"- First call to {signature}") called.add(signature) return _trace_calls