unsupported operand type in eventlet\semaphore.py (greenpool)

[MPagel]

Traceback (most recent call last):
  File "D:\Programs\Python\Python27\lib\site-packages\eventlet\hubs\hub.py", line 457, in fire_timers
    timer()
  File "D:\Programs\Python\Python27\lib\site-packages\eventlet\hubs\timer.py", line 58, in __call__
    cb(*args, **kw)
  File "D:\Programs\Python\Python27\lib\site-packages\eventlet\greenpool.py", line 141, in _do_map
    gi.spawn(func, *args)
  File "D:\Programs\Python\Python27\lib\site-packages\eventlet\greenpool.py", line 207, in spawn
    gt = self.pool.spawn(func, *args, **kw)
  File "D:\Programs\Python\Python27\lib\site-packages\eventlet\greenpool.py", line 71, in spawn
    self.sem.acquire()
  File "D:\Programs\Python\Python27\lib\site-packages\eventlet\semaphore.py", line 123, in acquire
    self.counter -= 1
TypeError: unsupported operand type(s) for -=: 'str' and 'int'

$ pip install eventlet
Requirement already satisfied: eventlet in d:\programs\python\python27\lib\site-packages
Requirement already satisfied: greenlet>=0.3 in d:\programs\python\python27\lib\site-packages (from eventlet)
Requirement already satisfied: enum-compat in d:\programs\python\python27\lib\site-packages (from eventlet)
Requirement already satisfied: enum34 in d:\programs\python\python27\lib\site-packages (from enum-compat->eventlet)

$ pip show python
Name: eventlet
Version: 0.20.0
Summary: Highly concurrent networking library
Home-page: http://eventlet.net
Author: Linden Lab
Author-email: eventletdev@lists.secondlife.com
License: UNKNOWN
Location: d:\programs\python\python27\lib\site-packages
Requires: greenlet, enum-compat

Python 2.7.11 (v2.7.11:6d1b6a68f775, Dec 5 2015, 20:32:19) [MSC v.1500 32 bit (Intel)] on win32

[temoto]

Can you share code to reproduce issue?

[temoto]

I think you have something like pool.resize('2'). Python doesn't automagically convert between numbers and strings.

[MPagel]

did a bit of further debugging. It's because my call to establish the pool was GreenPool(size=cfg.get('GLOBAL','Max_AWS_Connections')) where cfg is an object of type ConfigParser.RawConfigParser(). So, it's sending it in as a string. So, chalk this up to (mostly) end-user error. However, I recommend the following check in semaphore.py:

    def __init__(self, value=1):
        try:
            self.counter = long(value)
            te_text = ""
        except TypeError:
            te_text = "Type error in increment of counter. counter is now type {}. {} was type {}\n".format(type(self.counter),value,type(value))
        if ((self.counter <= 0) or (te_text != "")):
            raise ValueError(te_text+"Semaphore must be initialized with a positive number, got %s" % value)
        self._waiters = collections.deque()

[MPagel]

(note, this blocks the behavior of a GreenPool of size 0)

[temoto]

te = not isinstance(...) ;-)

[MPagel]

Thanks. Hopefully it should be Pagel-proof now :P

te = not isinstance(...) - um, yeah. /facepalm. You certainly have a better implementation now than copying value and then doing a try: counter += 0 as my first work-around was

[temoto]

The fix is merged in master 79292bd so it will be included in emergency bugfix release 0.20.1 soon. Thanks and have great time.