Re: [Libguestfs] [PATCH v3 1/2] New tool: virt-tail.
On Monday, 3 October 2016 15:07:10 CEST Richard W.M. Jones wrote:
This follows (tails) a log file within a guest, rather like
the regular 'tail -f' command. For example:
virt-tail -d guest /var/log/messages
---
Mostly LGTM, just a few notes.
+ guestfs_push_error_handler (g, NULL, NULL);
+ stat = guestfs_statns (g, filename);
+ guestfs_pop_error_handler (g);
+ if (stat == NULL) {
+ /* There's an error. Treat ENOENT as if the file was empty size. */
+ if (guestfs_last_errno (g) == ENOENT) {
+ time (&t);
+ file[i].mtime = t;
+ file[i].size = 0;
I'd set size as -1, otherwise this is considering the file as existing.
If virt-tail (wants to) behaves like `tail -f`, I'd:
- print an error/message line (not fatal) to warn that a file does not
exist
- when it appears, print that and start following it
+ /* If we get here, the file changed and we're going to
display
+ * something. If there is more than one file, and the file
+ * displayed is different from previously, then display the
+ * filename banner.
+ */
+ if (i != prev_file_displayed)
+ printf ("\n\n--- %s ---\n\n", filename);
+ prev_file_displayed = i;
I'd simplify the check as "if (argc > 1)", and remove the
"prev_file_displayed" variable (not used otherwise).
+ /* Do nothing until something happens on the disk image. Even
if
+ * the drive changes, always wait min. 30 seconds. For libvirt
+ * (-d) and remote sources we cannot check this so we have to use
+ * a fixed (5 minute) delay instead. Also we recheck every so
+ * often even if nothing seems to have changed. (XXX Can we do
+ * better?)
Should -s/--sleep-interval be available too, then?
Thanks,
--
Pino Toscano
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