Thursday, January 28, 2010

Bug in tornado-0.2

If you're using the latest packaged tornado distribution, tornado-0.2.tar.gz, then you might hit on the following bug when using AsyncHTTPClient:

ERROR:root:Exception in callback >
Traceback (most recent call last):
  File "/usr/local/lib/python2.6/dist-packages/tornado/", line 238, in _run_callback
  File "/usr/local/lib/python2.6/dist-packages/tornado/", line 214, in _perform
  File "/usr/local/lib/python2.6/dist-packages/tornado/", line 133, in remove_handler
IOError: [Errno 2] No such file or directory

For me, this was in the context of using a load testing script written by my colleague Dan Mesh. The script makes use of AsyncHTTPClient and runs several such objects in parallel, hitting a number of URLs. When the number of concurrent HTTP requests reaches around 100, I start seeing this error.

Solution? Install tornado from the latest source code on GitHub.

Friday, January 15, 2010


I've been holding back from using Twitter, which I generally still consider a waste of time. However, Bryan Landers convinced me that it's a good idea to tweet occasionally, for example when I post to my blog. Apparently many people (Bryan included) are past using RSS feed readers and other such antiquated tools that used to be popular in the first decade of this millennium. Also, there have been discussions within the SoCal Piggies group about increasing the communication and collaboration within the group, and with the Python community at large.

So...I created 2 twitter accounts, one for the SoCal Piggies (@socalpiggies) and one for myself (@griggheo). I'll generally post links to stuff I come across that might be of interest to people who share my interests.

Friday, January 08, 2010

Ian Bicking does it again with toppcloud

I haven't seen this on Planet Python yet, so I'll give it a shout out in the hope that more people will benefit from it. Via Ben Bangert, I heard yesterday about Ian Bicking's new brainchild, toppcloud -- a tool for automated deployments of cloud instances AND Python web apps. It's based on libcloud, and it currently only supports Rackspace's cloud, but it seems very promising already. The Python deployment seems to be inspired by Google AppEngine's deployment philosophy. I haven't played with it yet, but I'll do so soon and report back here. I've been using Fabric (and Puppet) successfully for automated application deployments, but toppcloud seems to be a very valuable tool to add to my arsenal.

Modifying EC2 security groups via AWS Lambda functions

One task that comes up again and again is adding, removing or updating source CIDR blocks in various security groups in an EC2 infrastructur...