Python v3 error: 'StdOutWrapper' object has no attribute 'flush'

[dolan-a]

When using python v3 to run locust, I occasionally get the following error with locust immediately terminating:

[2016-09-10 14:52:30,443] mybox/ERROR/stderr: Exception ignored in:
[2016-09-10 14:52:30,443] mybox/ERROR/stderr: <locust.log.StdOutWrapper object at 0x106aa79b0>
[2016-09-10 14:52:30,443] mybox/ERROR/stderr:
[2016-09-10 14:52:30,443] mybox/ERROR/stderr: AttributeError
[2016-09-10 14:52:30,443] mybox/ERROR/stderr: :
[2016-09-10 14:52:30,443] mybox/ERROR/stderr: 'StdOutWrapper' object has no attribute 'flush'
[2016-09-10 14:52:30,443] mybox/ERROR/stderr:

It looks like flushing was changed in python v3. See this SO q/a for more info.

[cgoldberg]

this was fixed when we added python3 support, but it looks like it was never merged to master:
548ffe7

[heyman]

Cherry-picked and pushed! Thanks!