[rancid] Getting notified on timestamp changes for IOS-XE devices

[heasley]

Mon, May 02, 2022 at 11:19:00PM -0400, Chuck Anderson:
> On Mon, May 02, 2022 at 04:38:31PM -1000, Steve O'Brien wrote:
> > I have looked at a bunch of similar questions but still have not figured
> > out how to get rancid to ignore the timestamp diff in IOS-XE devices.
> > 
> > - !Flash: bootflash: -rw-          5242880   May 1 2022 15:02:27 -10:00  ssd
> > + !Flash: bootflash: -rw-          5242880   May 2 2022 15:03:10 -10:00  ssd
> > 
> > It seems like it was a recent change, I just updated the IOS-XE devices to
> > Cisco IOS XE Software, Version 17.03.04
> > 
> > I am, and have been, using the standard cisco template
> > running rancid 3.13-3
> 
> It seems like a neverending losing battle filtering out newly
> oscillating command outputs.  I wonder if rancid should be enhanced to
> make the filter patterns configurable rather than requiring code to be
> written and/or have standard filters for dates/times in various formats.

What I've been thinking, and has been on my to do list, is that a general
filter mechanism would be useful.  Perform this user-defined filtering
before diffing & committing the rancidified config.  Rancid would expect
the filter to read from stdin and write to stdout.

in the case of this file timestamp oscillation, a user-definied filter
could remove or reformat the line.  That filter could be as simple as
"grep -v 'ssd$'", for example.

welcome comments on this.