Re: [libvirt] [PATCHv4 1/2] virsh: add new --details option to pool-list

On Tue, Jun 22, 2010 at 12:35:32PM -0600, Eric Blake wrote: > On 06/22/2010 12:24 PM, Hugh O. Brock wrote: > >> Correct, we shouldn't change this behaviour - it'll break apps parsing > >> the output > > > > FWIW Rich Jones complains that the output as it stands is nigh on > > unparseable anyway. Perhaps we should consider that a bug, and fix > > it... > > The new --details option is our chance to change output - it outputs > whatever format we want, because it is a new flag; Rich, do you have any > preferences about what it _should_ output? > > Here's what pool-list --details would currently do, if we applied > Justin's patch as-is (modulo no line wrapping added by my email client): Sorry, been away for a couple of weeks. > virsh # pool-list --details --all > Name State Autostart Persistent Capacity Allocation Available > --------------------------------------------------------------------------- > default running yes yes 1.79 TB 1.49 TB 304.77 GB > image_dir running yes yes 1.79 TB 1.49 TB 304.77 GB > tmp inactive no yes - - - One good thing, and several bad things about that. The good thing is that empty columns are presented with '-' which means you can use awk and sort -k to parse the output columnwise. The bad things: * Space within fields "1.79 TB" (awk / sort -k in fact _won't_ work). * Numeric fields aren't numbers: You can't sort -n on "1.79 TB", and you can't read that number into a script and do math on it. Most tools have a "-h" or "--human" option in order to generate human- readable numbers (without spaces), but default to just printing the raw numbers. * Unnecessary "-------" line. * Title line should be optional. Have a --no-title option or something like that to suppress it. * Does virsh still print an unnecessary blank line after the output? If so, stop doing that.