* Maxim Levitsky (mlevi...@redhat.com) wrote: > On Mon, 2020-01-27 at 14:44 +0100, Markus Armbruster wrote: > > Maxim Levitsky <mlevi...@redhat.com> writes: > > > > > On Wed, 2019-11-27 at 09:38 +0100, Markus Armbruster wrote: > > > > Title is too long. blockdev-hmp-cmds.c will become > > > > block/monitor/block-hmp-cmds.c in v2. With this in mind, suggest > > > > > > > > block/monitor: Prefer to use hmp_handle_error() to report HMP errors > > > > > > > > Maxim Levitsky <mlevi...@redhat.com> writes: > > > > > > > > > This way they all will be prefixed with 'Error:' which some parsers > > > > > (e.g libvirt need) > > > > > > > > Sadly, "all" is far from true. Consider > > > > > > > > void hmp_drive_add(Monitor *mon, const QDict *qdict) > > > > { > > > > Error *err = NULL; > > > > DriveInfo *dinfo = NULL; > > > > QemuOpts *opts; > > > > MachineClass *mc; > > > > const char *optstr = qdict_get_str(qdict, "opts"); > > > > bool node = qdict_get_try_bool(qdict, "node", false); > > > > > > > > if (node) { > > > > hmp_drive_add_node(mon, optstr); > > > > return; > > > > } > > > > > > > > opts = drive_def(optstr); > > > > if (!opts) > > > > return; > > > > > > > > > > > > hmp_drive_add_node() uses error_report() and error_report_err(). Easy > > > > enough to fix if you move the function here, as I suggested in my review > > > > of PATCH 8. > > > > > > To be honest that involves exporting the monitor_bdrv_states variable and > > > bds_tree_init, which were both static before, but I created a patch that > > > does that, > > > If that is all right, I'll squash it with some of my patches. > > > > > > > > > > > > > > drive_def() is a wrapper around qemu_opts_parse_noisily(), which uses > > > > error_report_err(). You can't change qemu_opts_parse_noisily() to use > > > > hmp_handle_error(). You'd have to convert drive_def() to Error, which > > > > involves switching it to qemu_opts_parse() + qemu_opts_print_help(). > > > > > > > > These are just the first two error paths in this file. There's much > > > > more. Truly routing all HMP errors through hmp_handle_error() takes a > > > > *massive* Error conversion effort, with a high risk of missing Error > > > > conversions, followed by a never-ending risk of non-Error stuff creeping > > > > in. > > > > > > Oops. Active can of worms is detected. Take cover! > > > > :) > > > > > > There must be an easier way. > > > > > > > > Consider vreport(): > > > > > > > > switch (type) { > > > > case REPORT_TYPE_ERROR: > > > > break; > > > > case REPORT_TYPE_WARNING: > > > > error_printf("warning: "); > > > > break; > > > > case REPORT_TYPE_INFO: > > > > error_printf("info: "); > > > > break; > > > > } > > > > > > > > Adding the prefix here (either unconditionally, or if cur_mon) covers > > > > all HMP errors reported with error_report() & friends in one blow. > > > > > > This is a very good idea. > > > If feels like this should be done unconditionally, although that will > > > break probably some scripts that depend on exact value of the error > > > message (but to be honest, > > > scripts shouldn't be doing that in first place). > > > > > > Doing that with cur_mon (took me some time to figure out what that is) > > > will > > > limit the damage but its a bit of a hack. > > > > > > > > > I think that this is a very good change anyway though so if everyone > > > agrees, > > > I will be more that happy to do this change. > > > Thoughts? > > > > I think adding an "error: " tag has been proposed before. > > > > I dislike overly decorated error messages, because decoration tends to > > obscure information. > > > > However, when there's significant non-error output, or even uncertainty > > of what's an error and what's something else, decoration can help. > Yes, also this way it is consistent
Yes I also like it; I wouldn't worry too much about things parsing error messages for the exact error message; if anything is doing that then the corresponding case needs to have big red flags around it. Dave > > > > Perhaps you can give some examples where the proposed decoration helps. > It helps to tag most monitor messages with error prefix which was the root > cause of > me starting to work on this refactoring. > You suggested this, and I kind of like that idea. > > > > > > > That leaves the ones that are still reported with monitor_printf(). > > > > Converting those to error_report() looks far more tractable to me. > > > > > > Yep, in fact I grepped the tree for monitor_printf and there are not > > > that much instances of this used for error reporting, so it might > > > be possible to have 'error' prefix on all monitor errors that way > > > and not only for the block layer. > > > > I figure "all" would be more useful than "just for the block layer". > Yep, the cover letter is outdated, now this patch series touch way > more that the block layer. > > Best regards, > Maxim Levitsky > > > -- Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK