vtysh / issue with command parser when some vty commands are set/unset upon configuration

[pguibert6WIND]

example:
When starting zebra, some vty commands are installed or not, depending on the vrf backend kind.
The issue #1976 illustrates the issue.

Actually, the vtysh parser that forges the vtysh client to populate the various vty commands does not know what is the vrf backend used. As such, it will parse both lines in zebra containing install_element, and will install it in vtysh client, thus resulting in the following message:

localhost.localdomain(config)# ip route 1.1.1.1/32 10.1.2.3 
% Ambiguous command: ip route 1.1.1.1/32 10.1.2.3 

this ticket should solve that issue; among possibilities to resolve this:

• solution 1 : do not make any differences at all between the various vrf backends
• solution 2 : vtysh should have an optional parameter that could permit at compilation time to know which command to installl/to ignore
• solution 3 : any proposal is welcome

[qlyoung]

#1 sounds good to me. Could you define a single command that handles both cases, rather than two commands with mutually ambiguous definitions that handle each case?

#2 is probably the wrong way to go. Being a shell, vtysh shouldn't know about things like what VRF backend is being used.

[pguibert6WIND]

issue 1968. I want to hide the table ID

[pguibert6WIND]

in 1968, I have 2 vty commands:;
A] ip route A.B.C.D E.F.G.H label
B] ip route A.B.C.D E.F.G.H
If vrf backend is default, then B command is installed.
If vrf backend is netns, then A command is installed

using solution#2 would know which command has to be parsed ( at compilation time ?)
using solution #1, I am puzzled because I don't want to offer on default vrf backend the ability to configure ( and display) label option.
how to handle that ?

• at the DEFUN_VTY definition ( arguments could be dynamically hidden ?)
• somewhere else ?

[qlyoung]

if (backend == netns)
   install_element(ip_route_netns_cmd);
else
   install_element(ip_route_cmd);

[pguibert6WIND]

This is what i did in #1968, but vtysh parser fails -> Ambiguous command:

I dont know how to put the if backend=netns on vtysh

[qlyoung]

You're right, I forgot you can't do it that way because extract.pl only sees installation calls and none of the surrounding logic. Instead you can do

DEFUN(...)
{
    if (user provided label && !netns) {
        "X is only available when running on network namespace"
        return CMD_WARNING;
    }
    ...
}

I agree it sucks.

[pguibert6WIND]

I updated #1976 accordingly.
let wait for 1976 CI success, and review, then, before closing the issue.

I would also check with Donald if he thinks it is ok to keep table as argument ( meaning that the parameter will be visible)