Re: [netmod] submodules the hidden benefits

Jan Lindblad <janl@tail-f.com> Thu, 06 August 2020 09:00 UTC

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From: Jan Lindblad <janl@tail-f.com>
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To: Mahesh Jethanandani <mjethanandani@gmail.com>
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Subject: Re: [netmod] submodules the hidden benefits
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I have to agree with the long list of "Costs" of submodules listed in this thread, and can attest to the brevity of the "Benefits" side. The globally accumulated amount of gray hairs produced by the YANG 1.0 submodule rules is best measured in cubic meters. 

The YANG 1.1 rules are much more in line with industry expectation in my experience, but the fact that the rules differ greatly between the two YANG versions with unchanged syntax and that many tools still do not properly support the YANG 1.1 submodule inclusion rules to this date (despite otherwise boasting YANG 1.1 support for long) is additional salt in a sore world.

One central point that has been missed in the discussion on the merits of modules vs. submodules is the implications this choice has on module versioning. Since versioning happens on the module/namespace level, there is a major difference between releasing 10 modules which are versioned independently, or one module with 10 submodules, which would have a single module version. If this point goes on the "Costs" or "Benefits" side in the book keeping, I'll leave open to interpretation.

/jan


> On 6 Aug 2020, at 00:43, Mahesh Jethanandani <mjethanandani@gmail.com> wrote:
> 
> A contrarian view:
> 
> I find the use of sub-modules helpful when I want to use separate files to maintain part of the module that is logically separate, while maintaining/restricting the use of them to a single namespace.
> 
> The fact that tools have a problem with trying to compile a sub-module can be addressed in the tools themselves.
> 
>> On Aug 5, 2020, at 2:44 PM, Reshad Rahman (rrahman) <rrahman=40cisco.com@dmarc.ietf.org <mailto:rrahman=40cisco.com@dmarc.ietf.org>> wrote:
>> 
>> Indeed
>> https://github.com/netmod-wg/yang-next/issues/26 <https://github.com/netmod-wg/yang-next/issues/26>
>> 
>> ´╗┐On 2020-08-05, 5:22 PM, "netmod on behalf of Vladimir Vassilev" <netmod-bounces@ietf.org on behalf of vladimir@lightside-instruments.com> wrote:
>> 
>>    On 05/08/2020 18.48, Juergen Schoenwaelder wrote:
>> 
>>> I personally meanwhile believe that sub-modules add complexity with
>>> little extra value but this view surely is not shared by others.
>> 
>>    +1. IMO removing sub-modules from YANG 2.0 should be on the list of 
>>    proposed changes.
>> 
>>    /Vladimir
>> 
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