Unhandled exception in asynchat can take the entire Zope system down

[Chui Tey]

line 420 of asyncore's error handler calls close()
this calls producer's more() method.
sometimes producers can throw exceptions (in my case, reading from UNC path fails with IOError 22 when the system doesn't have sufficient resources), and this is not caught, bringing down the entire system.
The net result is the entire process comes down.

Traceback (most recent call last):
  File "c:\dw304\lib\python\Zope\Startup\run.py", line 52, in ?
    run()
  File "c:\dw304\lib\python\Zope\Startup\run.py", line 21, in run
    start_zope(opts.configroot)
  File "c:\dw304\lib\python\Zope\Startup\__init__.py", line 68, in start_zope
    Lifetime.loop()
  File "c:\dw304\lib\python\Lifetime.py", line 43, in loop
    lifetime_loop()
  File "c:\dw304\lib\python\Lifetime.py", line 70, in lifetime_loop
    asyncore.poll(timeout, map)
  File "c:\dw304\bin\lib\asyncore.py", line 125, in poll
    write(obj)
  File "c:\dw304\bin\lib\asyncore.py", line 81, in write
    obj.handle_error()
  File "c:\dw304\lib\python\ZServer\medusa\http_server.py", line 445, in handle_error
    asynchat.async_chat.handle_error (self)
  File "c:\dw304\bin\lib\asyncore.py", line 420, in handle_error
    self.close()
  File "c:\dw304\lib\python\ZServer\HTTPServer.py", line 350, in close
    p.more() # free up resources held by producer
  File "c:\dw304\lib\python\ZServer\Producers.py", line 107, in more
    return self.iterator.next()
  File "C:\DW304\DW30500\lib\python\DataWrks\Iterators.py", line 71, in next
    data = self._iterator.next() # throws StopIteration
  File "c:\dw304\lib\python\ZPublisher\Iterators.py", line 43, in next
    raise IOError(22, '')
IOError: (22, '')

if we don't want to patch asyncore, then HTTPServer should catch the error.

[Andreas Jung (ajung)]

Changes: submitter email, importance (critical => medium)

[Colin Watson (cjwatson)]

The zope2 project on Launchpad has been archived at the request of the Zope developers (see https://answers.launchpad.net/launchpad/+question/683589 and https://answers.launchpad.net/launchpad/+question/685285). If this bug is still relevant, please refile it at https://github.com/zopefoundation/zope2.