How sys.setprofile + greenlet.settrace can trace all calls/switches/returns

tracing_greenlets_001

#!/usr/bin/env python

import greenlet, time, sys

def sys_profiler(frame, event, arg):
    if event == 'call' or event == 'return':
        code = frame.f_code
        print('g{} {} {}:{} {}()'.format(id(greenlet.getcurrent()), event, code.co_filename, code.co_firstlineno, code.co_name))

sys.setprofile(sys_profiler)

def green_tracer(event, args):
    if event == 'switch' or event == 'throw':
        origin, target = args
        print('g{} -> g{}'.format(id(origin), id(target)))

greenlet.settrace(green_tracer)

def alice_func():
    print('alice: 1')
    bob = greenlet.greenlet(bob_func)
    bob.switch()
    print('alice: 2')
    bob.switch()

def bob_func():
    print('bob: 1')
    alice.switch()
    print('bob: 2')

alice = greenlet.greenlet(alice_func)
alice.switch()
time.sleep(50)

"""
g140482924548976 -> g140482924548176
g140482924548176 call ./test1.py:20 alice_func()
alice: 1
g140482924548176 -> g140482924548336
g140482924548336 call ./test1.py:27 bob_func()
bob: 1
g140482924548336 -> g140482924548176
alice: 2
g140482924548176 -> g140482924548336
bob: 2
g140482924548336 return ./test1.py:27 bob_func()
g140482924548336 -> g140482924548176
g140482924548176 return ./test1.py:20 alice_func()
g140482924548176 -> g140482924548976
"""