Proposal: change compare_config on merge operation about napalm-ios

[mirceaulinic]

That's fantastic @ktbyers!

I would be curious if NX-OS has something similar we could use. I will have a look soon and check that out!

[ktbyers]

One more example, an ACL change where the order of the ACL has changed, but all the lines entirely match for ACL entries.

Router config:

ip access-list extended TEST1
 permit ip any host 1.1.1.1
 permit ip any host 1.1.1.2
 permit ip any host 1.1.1.3
 permit ip any host 1.1.1.4
 permit ip any host 1.1.1.5
 permit ip any host 2.2.2.2

New merge file:

logging buffered 12000
no logging console

ip access-list extended TEST1
 permit ip any host 2.2.2.2
 permit ip any host 1.1.1.1
 permit ip any host 1.1.1.2
 permit ip any host 1.1.1.3
 permit ip any host 1.1.1.4
 permit ip any host 1.1.1.5

What Cisco IOS reports:

show archive config incremental-diffs flash:/merge_config.txt
!List of Commands:
!
!The following order-dependent line(s) were re-ordered
!ip access-list extended TEST1
! permit ip any host 1.1.1.1
! permit ip any host 1.1.1.2
! permit ip any host 1.1.1.3
! permit ip any host 1.1.1.4
! permit ip any host 1.1.1.5
end
!No changes were found

What napalm-ios would show:

+!The following order-dependent line(s) were re-ordered
+!ip access-list extended TEST1
+! permit ip any host 1.1.1.1
+! permit ip any host 1.1.1.2
+! permit ip any host 1.1.1.3
+! permit ip any host 1.1.1.4
+! permit ip any host 1.1.1.5

[ktbyers]

If the 'show archive config incremental-diffs flash:/merge_config.txt', then it will fall back to old method and print some warning about this.

[jedelman8]

Very cool. Good find @ktbyers with this incremental-diffs command.

@mirceaulinic nothing like this I'm aware of on NX-OS unless we use a system generated checkpoint file (which is how napalm works today for a config replace).

[dbarrosop]

+100000

This is great! Any caveat like OS support or something that we should add to the documentation?

[mirceaulinic]

Thanks for info @jedelman8!

[ktbyers]

@dbarrosop I didn't see any new caveats, but let me dig into it some more. I did add a handler so if the command fails (i.e. '% Invalid' it will fall back to the old way).

[ktbyers]

Working branch is here:

https://github.com/ktbyers/napalm-ios/tree/devel

Note, I still have some print debugging in the code and some other minor things need cleaned up.

[ktbyers]

Implemented here: #100