On Thu, Nov 29, 2012 at 07:53:10PM +0100, Thomas Graf wrote: > On 11/29/2012 06:23 PM, Ben Pfaff wrote: > >It's better in that it would simply report whether the port was > >successfully added in an unambiguous fashion, instead of shipping > >possibly a lot of possibly irrelevant log data to the user, often > >regardless of whether the port was added successfully or not. Your own > >example shows this. > > It would basically allow to print "Error: Unable to add port foo to > bridge bar" which is not really helpful.
It tells a human user that the operation failed. It could also notify a script that the operation failed, e.g. if we decided to return a nonzero exit status. (ovs-vsctl is intended for use by both humans and programs.) I'm perfectly willing to add another column, or use another existing column, to provide more detail about why a particular port or interface cannot be added. > >Also, the database is designed to maintain state. This patch series > >instead tries to use it in a request/reply manner. That works OK with a > >single client but it's going to fall down whenever there's more than one > >client making requests in parallel. > > Not sure why reading the "ofport" column would not be request/reply > manner. The "ofport" column reports the OpenFlow port number used by a particular interface, which is part of the state of the OpenFlow switch. > Despite of that, I _do_ consider the "console" content as state. It > always reflects the current side effects, exceptions and informational > messages based on the current active configuration. It would contain that, but it might also contain essentially unrelated information that just happens to be logged during switch reconfiguration, which in some cases can take several trips through ovs-vswitch'd main loop. Using a "console" doesn't actually tell you directly whether the operation you executed succeeded or failed. You may be able to figure that out as a human by carefully reading the output. But there's likely to be a lot of irrelevant spew, especially in a large system with thousands of interfaces. This is also a rather unconventional design. Can you point me to other systems that print a complete dump of their log messages to the console, regardless of relevance, after a single operation? I would like to read up on user feedback to such designs, or rely on my own experience if I happen to already use such a system without realizing it. Thanks, Ben. _______________________________________________ dev mailing list dev@openvswitch.org http://openvswitch.org/mailman/listinfo/dev
