[rancid] sorting output from custom commands...

[john heasley]

Tue, Sep 28, 2010 at 06:06:30PM +0100, Jon Peatfield:
> I added a quick hack to our rancid (2.3.4) setup to record the output of  
> running:
>
>   show cdp neighbors detail
>
> to hrancid and rancid (we only have Cisco and HP procurve switches).
>
> On the newer versions of the HP porocurve firmware (all 2610-xx models)  
> each (cisco 79xx) phone device shows up as two device-ids, and it appears 
> that every time a handset is connected those devices appear in a random  
> order.
>
> So at the moment we get spurious change messages swapping the order of 
> the two entries (both on the same port).
>
> I'm not very familiar with how ProcessHistory works, so I don't know if  
> there is a trick I can use to get it to do the sorting for me.  I did  
> already write a piece of code to store the data in a hash by device-id 
> and only call ProcessHistory when we notice that the port in the output 
> has changed, but I lost that by accidentally zapping the directory I was  
> testing in (oops).  I can re-do that work easily enough but since other  
> stuff has to handle output in different orders I wonder if I'm wasting my 
> time...

ProcessHistory(tag, command, command_arg, data)

data is added the buffer, by command with command_arg (if specified),
unless tag or command has changed since the last call, in which case
the buffer would be flushed before calling command.

a good example, where $aclsort = "ipsort" (the function)

        # order access-lists 
        /^access-list\s+(\d\d?)\s+(\S+)\s+(\S+)/ &&
            ProcessHistory("ACL $1 $2","$aclsort","$3","$_") && next;