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.

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