Yang compilation fails

YANG
1

Hi, I am getting the following error on compilation:

eci-bgp-l3vpn-dev.yang:56: error: the type leafref (defined at ./ietf-interfaces.yang:54) is converted to 'string' when part of a union

The following are the related yang files:

ietf-interfaces.yang

typedef interface-ref {
    type leafref {
      path "/if:interfaces/if:interface/if:name";
    }

eci-bgp-l3vpn-dev.yang

   typedef lif-type {
                 type union {
                            type if:interface-ref;
                            type string ;  
                            }
                     }

What is the issue here?
Please assist.

Thanks in advance.

2

It’s actually a warning, but I guess you use --fail-on-warnings, which is generally a Good Idea™.

You have encountered one of the exceptions in the YANG 1.1 support - from the “YANG 1.1” section of the confdc(1) manual page:

o   Type leafref in unions are not validated, and treated as a string
    internally.

(In YANG 1, type leafref is not allowed to be part of a union.)

You can prevent the warning from becoming an error when you use --fail-on-warnings by passing -W YANG_ERR_UNSUPPORTED_TYPE_IN_UNION to confdc, or you can suppress even the warning by passing -w YANG_ERR_UNSUPPORTED_TYPE_IN_UNION.

3

Hi,

Thanks for the suggestion. I added this -W YANG_ERR_UNSUPPORTED_TYPE_IN_UNION to confdcbut it not work. The compilation failed with the same error.

I also removed --fail-on-warnings and yet got the same message.
Doesn’t this mean that it is an error and not warning?

How should I approach this issue?

Thanks,
Ramakrishnan

4

I’m afraid you must be making some mistake when changing the compilation options - maybe you have some generic make target that is applied? I verified what I wrote before posting - here it is, where I faked your eci-bgp-l3vpn-dev.yang module as containing only the typedef, and used ietf-interfaces revision 2014-05-08:

$ confdc -c eci-bgp-l3vpn-dev.yang
eci-bgp-l3vpn-dev.yang:12: warning: the type leafref (defined at ./ietf-interfaces@2014-05-08.yang:54) is converted to 'string' when part of a union
$ echo $?
0
$ confdc -c --fail-on-warnings eci-bgp-l3vpn-dev.yang
eci-bgp-l3vpn-dev.yang:12: error: the type leafref (defined at ./ietf-interfaces@2014-05-08.yang:54) is converted to 'string' when part of a union
$ echo $?
1
$ confdc -c --fail-on-warnings -W YANG_ERR_UNSUPPORTED_TYPE_IN_UNION eci-bgp-l3vpn-dev.yang
eci-bgp-l3vpn-dev.yang:12: warning: the type leafref (defined at ./ietf-interfaces@2014-05-08.yang:54) is converted to 'string' when part of a union
$ echo $?
0
$ confdc -c --fail-on-warnings -w YANG_ERR_UNSUPPORTED_TYPE_IN_UNION eci-bgp-l3vpn-dev.yang
$ echo $?
0
$
5

Thanks a lot for looking into this.

I have something like this,
../../cml/confd/kvm/Confd/bin/confdc -c --deviation eci-bgp-l3vpn-dev.yang -o eci-bgp-l3vpn-dev.fxs --verbose --fail-on-warnings -w YANG_ERR_UNSUPPORTED_TYPE_IN_UNION eci-bgp-l3vpn.yang

Do you see any issues with the above?

Thanks in advance.

6

Hi,

There was one more place where this flag was needed.
Added it and now it works fine.

Thanks!

7

Good to hear! About the confdc command you quoted, it’s a bit weird in that you are compiling eci-bgp-l3vpn.yang but request that the fxs file should be called eci-bgp-l3vpn-dev.fxs. In principle you can call the fxs files whatever you want, but it gets confusing if they don’t match the .yang name - and in some cases you actually need to compile and load deviation modules “themselves”.

8

Hi,

Thanks for your response. I could compile the earlier part without any issues but now I see something like this.

> kill old Confd process.... --stop
> connection refused (stop)
> Confd process starts.... --verbose
> Failed to load file /root/kvmpackage/Confd/etc/confd/eci-bgp-l3vpn-aug.fxs: Missing augment path /network-instances/network-instance/vrf-label in module ietf-network-instance, augmented from module eci-bgp-l3vpn-aug.
> Daemon died status=21
> connection refused (wait_phase0)
> DEBUG Failed to connect to ConfD: Connection refused
> confd_load: 279: maapi_connect(sock, addr, addrlen) failed: system call failed (24): Failed to connect to ConfD: Connection refused
> connection refused (start_phase2)

What does this failed to load mean?

Does this mean the eci-bgp-l3vpn-aug.fxs was not compiled properly?

Thanks in advance.

9

Hi,

Can you please answer my question?

Thanks,
Ramakrishnan

10

Hi, Take a look at the YANG RFC to get the details on how YANG augmentation statements work.
https://tools.ietf.org/html/rfc7950#section-7.17

11

That’s a possibility (for some value of “properly”), but since we don’t know what’s in your modules, it’s hard to say. Generally speaking, if module A augments /b:foo/b:bar in module B, when module A is compiled, the compiler will load module B and verify that the path /foo/bar actually exists there (and refers to an augmentable node, not e.g. a leaf or leaf-list). If you then at load time get an error saying that /foo/bar in module B can’t be found, it means that the compiled B.fxs doesn’t have that node.

One possible reason is that module B was changed and the bar node was removed, but module A was not compiled with the new version of module B. Another is that B wasn’t actually changed, but a module C that removes bar via deviate not-supported is used when compiling B, but not when compiling A. Looking at your specific case, there is no node called vrf-label in the current version of ietf-network-instance (at draft-ietf-rtgwg-ni-model-12). Perhaps it existed in an earlier version, and you still have that version in the path when compiling eci-bgp-l3vpn-aug, while ietf-network-instance.fxs was compiled from the current version?

By the way, posting a followup re-asking for an answer just a few hours after posting your question might be considered bad form in a forum like this, and is in any case not likely to get you an answer any sooner.