[Freeipa-devel] Structured DNS record API proposal

[Adam Young]

On 09/20/2011 11:11 AM, Martin Kosek wrote:
> On Tue, 2011-09-20 at 10:02 -0400, Adam Young wrote:
>> This discussion got me thinking, always a dangerous proposal:
>>
>> We are currently exposing record add with the lie  that  when you add a
>> record, it has a type.  THe reality is that a record is just this big
>> collection of multi value attributes, and each of those  is the "type"
>> of the record.
> The way I see it is that we have different types of Resource Records
> with a (domain) name that can be shared.
>
>>
>> If all of the 'records'  have the same idnsname, then they really fall
>> under the same Record object in LDAP.
> Yes.
>
>> What if we focuses on the attribtutes themselves, and add the type info
>> there.
> I thought we do this already.
>
>>
>> Pie in the sky proposal.   Treat it as a starting point:
>>
>>   From the webui perspective
>> dnsrecord-add   allows the case where it just has the the idnsname with
>> no "records"
>>
>> dnsrecordattr-mod  takes record type specific values.
>>
>> To add a location entry:
>>
>> ipa dnsrecordattr-mod --append location --lat-deg=INT --lat-min=INT --lat-sec=FLOAT --lat-dir=ENUM --lon-deg=INT --lon-min=INT --lon-sec=FLOAT --lon-dir=ENUM --alt=FLOAT --h-precision=FLOAT --v-precision=FLOAT
>>
>>
>> And to remove it
>>
>> ipa dnsrecordattr-mod --remove location --lat-deg=INT --lat-min=INT --lat-sec=FLOAT --lat-dir=ENUM --lon-deg=INT --lon-min=INT --lon-sec=FLOAT --lon-dir=ENUM --alt=FLOAT --h-precision=FLOAT --v-precision=FLOAT
> So if user would want to remove a LOC record, he would have to pass all
> these attributes to refer which attribute value to remove?
I think that is the case anyway.  Since a DNS record is really just an 
multivalue attribute,   you would now have to do  a dns-record-mod with 
the list of all LOC records that you don't want to delete.  I used this 
as an example because it is the most complex case.

Just thinking it through...I'm not certain I like the "one command per 
record type"  as it changes a lot of other assumptions.  DNS is a wierd 
beast already.

I've spent a lot of time on the DNS ui, and it is pretty tricky  to get 
right.  I'm trying to balance the PI against efficient usage.

What we really need for the fields is a way to specify the format for a 
given field, much like the format strings used for group names.  For 
example, the LOC  record  is really

<owner>  <TTL>  <class>  LOC d1 [m1 [s1]] {"N"|"S"}  d2 [m2 [s2]] {"E"|"W"}
                           alt["m"] [siz["m"]     [hp["m"] [vp["m"]]]]


And all the WebUI needs is a way to specify that format  to validate.



We need a better approach than setattr/add attr, but it should  not be 
specific to the DNS use case.    Let me frame the problem this way:

Extend the IPA plugin API to allow for multivalue attributes, composed 
of multiple fields, where the fields can have format strings.

Solve this design issue, and the DNS design becomes an application of it.