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On 11/07/2012 02:52 AM, Vishvananda Ishaya wrote:
> On Nov 2, 2012, at 6:40 PM, Adam Young <ayoung at redhat.com> wrote:
>
>> Since Eventlet is based on continuations instead of threads or processes, any call that blocks is going to lock up the webserver. That is any I/O at all.  Thus, when trying to figure out how best to call the OpenSSL functions from Eventlet, I settled on what I thought would be the best tested approach: spin it off as a separate process.  And it seemed to work.
>>
>> Well, it doesn't work.  The Eventlet library does not properly Monkey patch the subprocess calls from Python.  While this is something we should patch upstream in Eventlet,  we need something to deal with the existing Eventlet library for Grizzly development.
>>
>> I've been trying to make it possible to run Keystone (and the other services eventually) in Apache.  Thus, the simple solution of replacing
>>
>> import subprocess
>>
>> with
>>
>> import eventlet.green.subprocess
>>
>> Won't work.  It solves the problem in Eventlet, but not apache.
> Why not just do the standard
>
> try:
>    from eventlet.green import subprocess
> except ImportError:
>    import subprocess
>
> We've used that in various places in nova before.

That logic is incorrect.  That  that logic is "if eventlet is available, 
use it." If you are trying to run Keystone in HTTPD, but eventlet 
happens to be installed because you are running say, nova on the same 
server, it will pick up eventlet from the site-libs. Thus, the logic we 
want is "If you are running in an eventlet server, use the eventlet 
subprocess."  A good rule of thumb is that the eventlet code should not 
be referenced from any files except those that explicitly choose to run 
eventlet.  In Keystone, that is the server.

>
> Vish
>
>
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