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Subject: Re: [DISCUSS] Increase stability on o.a.h.h.Tag?
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From: Josh Elser <elserj@apache.org>
Message-ID: <0eb2ac82-5903-796b-35b8-f9aefdb1c27d@apache.org>
Date: Fri, 22 Sep 2017 12:07:54 -0400
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archived-at: Fri, 22 Sep 2017 16:07:59 -0000

I can appreciate how we've gotten to this point, it just struck me 
extremely odd that the contents of a Tag weren't expected to be accessed 
by users. "Arbitrary metadata that rides along with a cell, you just 
can't see that metadata" ;)

I totally understand not wanting to let another thing come into 2.0. 
Like MikeD said, let's hope for a faster 3.0 and we can slate this for 
that time.

Thanks for entertaining the discussion. We'll just deal with the 
"downstream pain" for 2.0.

On 9/22/17 1:32 AM, ramkrishna vasudevan wrote:
> CellUtil  similar type of methods. Coming to Tags yes there are not much
> cases where clients can directly set Tags. And I think we don't expose any
> APIs which allow you to use mutations with Tags. So probably moving to
> LimitedPrivate is better and mark with Evolving if there are some users
> depending on the internals of Tags and its impl. But this will be a One of
> case.
> 
> And also since Tags are internal ideally the CellUtil#getTAgs() should have
> been in another Util method that is exposed with LimitedPrivate and also
> Tags if tags should be made LimitedPRivate. So this may help in not having
> a PRivate interface like Tag in a public CellUtil class.
> 
> 3.0 is fine but need some clean up in 2.0? Indicating what could happen
> going forward from 2.0?
> 
> Regards
> Ram
> 
> 
> 
> On Fri, Sep 22, 2017 at 2:59 AM, Sean Busbey <busbey@apache.org> wrote:
> 
>> Yeah. I mean, I think we should improve  the situation. Just think
>> it's too much to bite off at this stage of 2.0, we can aim for 3.0 and
>> start working in some tooling to help us.
>>
>> On Thu, Sep 21, 2017 at 3:35 PM, Josh Elser <elserj@apache.org> wrote:
>>> That really makes me groan (we have downstream users depending on code
>> we've
>>> explicitly said "don't use"), but if that's what it is given the current
>>> state, so be it. My complaining won't fix it.
>>>
>>> Thanks.
>>>
>>>
>>> On 9/21/17 4:25 PM, Sean Busbey wrote:
>>>>
>>>> We have lots of examples of including non-Public stuff in Public APIs.
>>>> we have docs that advise folks to be wary on relying on them beyond
>>>> opaque symbols.
>>>>
>>>> ref: http://hbase.apache.org/book.html#hbase.client.api.surface
>>>>
>>>> On Thu, Sep 21, 2017 at 3:21 PM, Josh Elser <elserj@apache.org> wrote:
>>>>>
>>>>> I was going to suggest LimitedPrivate in my original, but this doesn't
>>>>> make
>>>>> sense as we're exposing Public API via CellUtil.
>>>>>
>>>>> It seems odd to me that we wouldn't treat the cell tags as a supported
>>>>> API
>>>>> call. However, I'm happy to remain "confused" if the rest of folks
>> don't
>>>>> consider tags to be intended for users :)
>>>>>
>>>>>
>>>>> On 9/21/17 3:15 PM, Ted Yu wrote:
>>>>>>
>>>>>>
>>>>>> Can we mark Tag LimitedPrivate ?
>>>>>>
>>>>>> We know how ATS uses Tags so it should be straight forward to keep
>> their
>>>>>> usage intact.
>>>>>>
>>>>>> On Thu, Sep 21, 2017 at 12:03 PM, Josh Elser <elserj@apache.org>
>> wrote:
>>>>>>
>>>>>>> Hiya,
>>>>>>>
>>>>>>> (Background, I'm starting what is likely to be an onerous task of
>>>>>>> looking
>>>>>>> through downstream components and seeing what is broken with the
>> latest
>>>>>>> hbase-2.0.0*)
>>>>>>>
>>>>>>> Looking at YARN's use of HBase for the Application TimelineServer, I
>>>>>>> see
>>>>>>> that they're relying on the Tag interface.
>>>>>>>
>>>>>>> Presently, Tag is marked as Private, yet we expose it via the Public
>>>>>>> CellUtil.
>>>>>>>
>>>>>>> My gut reaction is that we should bump Tag up Public since the intent
>>>>>>> is
>>>>>>> for downstream users to, ya know, use those Tags. Any objections?
>>>>>>>
>>>>>>> If we don't want to expose Tag, we should make a pass over the Public
>>>>>>> methods and mark them as Private (so not as to provide a Public
>> method
>>>>>>> with
>>>>>>> Private objects). CellUtil#getTag(Cell, byte) would be one such
>>>>>>> example.
>>>>>>>
>>>>>>> - Josh
>>>>>>>
>>>>>>
>>>>>
>>>
>>
>