According to Nick Johnson (a former App Engine team member) os.environ is
threadsafe:
But what if my app makes use of 'os.environ' or other CGI-isms, you ask?
All is not lost. The smart folks on the Python 2.7 runtime team foresaw
that some apps will inevitably do this, and built in a workaroun
In the python27 runtime, os.environ is thread safe since it is implemented
as request/thread-local. However, this means that changes in one request
will not be visible by other requests. Also, since os.environ is
conceptually a global dictionary, I would recommend against writing to it
whenever
NOTE that if you have an instance (and hence a VM) running, then it has a
thread that serves incoming requests sequentially as needed.
A new thread is not started for each request, it can be one thread serving
requests in a loop.
So. making changes to Thread Local variables (and hence envir
