Call Graph Generation (as seen on the Don't Use This Code mailing list)

callgraph.py

#!/usr/bin/env python3

from networkx import DiGraph
from networkx.drawing.nx_pydot import to_pydot
from contextlib import contextmanager
from sys import setprofile
from collections import namedtuple

class Ident(namedtuple('IdentBase', 'filename lineno name')):
    def __str__(self):
        return f'"{self.filename}\n{self.lineno}\n{self.name}"'

@contextmanager
def callgraph(root=Ident('<context manager>', -1, '')):
    def cb(frame, event, arg):
        nonlocal current
        if current is root and g.out_edges(root):
            return
        if event == 'call':
            code = frame.f_code
            g.add_edge(current, current := Ident(code.co_filename, code.co_firstlineno, code.co_name))
        elif event == 'return':
            current = next(g.predecessors(current), root)
    g = DiGraph()
    g.add_node(current := root)
    try:
        setprofile(cb)
        yield g
    finally:
        setprofile(None)

# NOTE|dutc: don't uncomment this is if you want to sleep at night
#  from io import StringIO
#  data = StringIO('''
#  a, b, c
#  1, 10, 100
#  2, 20, 200
#  ''')
#  from pandas import read_csv
#  with callgraph() as cg:
#     df = read_csv(data)

#  from matplotlib.pyplot import subplots
#  with callgraph() as cg:
#     subplots(2, 2)

#  from pandas import date_range
#  with callgraph() as cg:
#      date_range(start='2020-01-01', end='2020-07-04', tz='America/Los_Angeles')

#  def f(): g()
#  def g(): h(); k()
#  def h(): pass
#  def k(): pass
#  with callgraph() as cg:
#     f()

files = {n.filename for n in cg.nodes()}
funcs = {n.name for n in cg.nodes()}
print(f'{len(files)} files, {len(funcs)} funcs')

# # NOTE|dutc: requires python-pydot
from matplotlib.pyplot import imshow, show, axis
from matplotlib.image import imread
from io import BytesIO
(png := BytesIO()).write(to_pydot(cg).create_png(prog='dot')); png.seek(0)
axis('off'); imshow(imread(png), aspect='equal'); show()