Open Stack

On Fri, May 13, 2016 at 1:12 PM, Adam Young <ayoung at redhat.com> wrote:

> On 05/13/2016 12:52 PM, Monty Taylor wrote:
>
>> On 05/13/2016 11:38 AM, Eric Larson wrote:
>>
>>> Monty Taylor writes:
>>>
>>> On 05/13/2016 08:23 AM, Mehdi Abaakouk wrote:
>>>>
>>>>> On Fri, May 13, 2016 at 02:58:08PM +0200, Julien Danjou wrote:
>>>>>
>>>>>> What's wrong with pymemcache, that we picked for tooz and are using
>>>>>> for 2 years now?
>>>>>>
>>>>>>   https://github.com/pinterest/pymemcache
>>>>>>
>>>>> Looks like a good alternative.
>>>>>
>>>> Honestly, nobody should be using pymemcache or python-memcached or
>>>> pylibmc for anything caching related in OpenStack. People should be
>>>> using oslo.cache - however, if that needs work before it's usable,
>>>> people should be using dogpile.cache, which is what oslo.cache uses on
>>>> the backend.
>>>>
>>>> dogpile is pluggable, so it means that the backend used for caching
>>>> can be chosen in a much broader manner. As morgan mentions elsewhere,
>>>> that means that people who want to use a different memcache library
>>>> just need to write a dogpile driver.
>>>>
>>>> Please don't anybody directly use memcache libraries for caching in
>>>> OpenStack. Please.
>>>>
>>>> Using dogpile doesn't remove the decision of what caching backend is
>>> used. Dogpile has support (I think) for all the libraries mentioned here:
>>>
>>>
>>> https://bitbucket.org/zzzeek/dogpile.cache/src/87965ada186f9b3a4eb7ff033a2e31437d5e9bc6/dogpile/cache/backends/memcached.py
>>>
>>>
>>> Oslo cache would need to be the one making decision as to what backend
>>> is used if we need to have something consistent.
>>>
>> I do not understand why oslo.cache would make a backend decision. It's a
>> config-driven thing. I could see oslo.cache having a _default_ ... but
>> having oslo.cache use dogpile.cache and then remove the ability for a
>> deployer to chose which caching backend dogpile uses seems more than
>> passing strange to me.
>>
>
> With oslo cache, you say "I want memcache" and Oslo picks the driver.
> Standardizes the implementation within OpenStack.
>
>
You can also specify pylibmc or BMemcached, or Redis, or <my cool driver
that lives in entry point XXXX> as well when issuing the .configure() to
the dogpile.cache region. The default oslo.cache uses is python-memcached,
but that could be fixed easily.

>
>
>> With that said, it is important that we understand what projects have
>>> specific requirements or have experienced issues, otherwise there is a
>>> good chance teams will hit an issue down the line and have to work
>>> around it.
>>>
>> Yup. Totally agree. I certainly don't want to imply that there aren't
>> issues with memcache libs nor that they shouldn't be fixed. Merely
>> trying to point out that individual projects programming to the
>> interface of any of the libs is a thing that should be fixed.
>>
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>
>
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