In the abstract DNSService's _dns_handle_tcp method, error handling
is broken in a way that stops the main loop for handling TCP
connections.
Because socket.timeout is a subclass of socket.error, the error
handling block for socket.timeout is never reached.
Because of this, error handling of a TCP timeout is sent to the
socket.error block. Due to the way eventlet hijacks these errors,
the errorcode is not available and a KeyError is raised. This
KeyError interferes with the main loop because it is not caught.
Further improvement may include ensuring that these main loops
can never die due to unexpected exceptions.
Many thanks to Erik Andersson for pointing out the issue, which
was seemingly innocuous but ended up being the cause of our
problems.
Reviewed: https:/ /review. openstack. org/284912 /git.openstack. org/cgit/ openstack/ designate/ commit/ ?id=d5d0706705c 64dba847cea5a30 b4a6be39ecd63f
Committed: https:/
Submitter: Jenkins
Branch: master
commit d5d0706705c64db a847cea5a30b4a6 be39ecd63f
Author: Rahman Syed <email address hidden>
Date: Thu Feb 25 14:12:53 2016 -0600
Improve error handling for TCP connections
In the abstract DNSService's _dns_handle_tcp method, error handling
is broken in a way that stops the main loop for handling TCP
connections.
Because socket.timeout is a subclass of socket.error, the error
handling block for socket.timeout is never reached.
Because of this, error handling of a TCP timeout is sent to the
socket.error block. Due to the way eventlet hijacks these errors,
the errorcode is not available and a KeyError is raised. This
KeyError interferes with the main loop because it is not caught.
Further improvement may include ensuring that these main loops
can never die due to unexpected exceptions.
Many thanks to Erik Andersson for pointing out the issue, which
was seemingly innocuous but ended up being the cause of our
problems.
Closes-bug: 1549980 42cbd56e4d296e0 83f8fcbbae5
Change-Id: I47e1260a0818cc