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If the only concern is continuing to have a nosql solution, we should just add it. It should only be a day or two of work to put it in. Vish On Sep 10, 2010, at 10:13 AM, Rick Clark wrote: > I think the abstraction is good, but I would rather wait until we have a > chance to add redis support. > > > On 09/10/2010 12:08 PM, Vishvananda Ishaya wrote: >> I don't understand the comment that this doesn't play nicely with >> non-relational data stores. There is a very clear abstraction layer >> db/api.py that would allow a different backend to be plugged in >> regardless of whether sqlalchemy ever supports it. I don't think it >> would be too difficult to add db/redis/api.py to this system. >> >> The one possible gotcha is that there isn't a clear definition of the >> properties that each object needs to have anywhere outside of >> sqlalchemy/models.py and the relations that are needed. This >> ultimately should be fixed with either documentation or some kind of >> middle tier classes that define the needed properties. >> >> Delaying until after austin would be a bit troublesome for us since >> we have to move of of redis. That means a pretty strongly diverged >> branch and any features that anso is working on will probably have to >> be delayed as well. >> >> Vish >> >> On Sep 10, 2010, at 9:56 AM, Jay Pipes wrote: >> >>> Hi Vish, >>> >>> Such a large patch has taken me quite some time to digest. There >>> is a larger discussion on large patches without any specifications, >>> but I'll leave that for a later time! :) >>> >>> I am torn on this one, mostly because I spent a bunch of time >>> attempting to do the datastore refactoring myself (as did Justin >>> Santa Barbara), and thus I know the dragons that live in this layer >>> of the code :) >>> >>> One of the things that both Justin and I had tried was to keep an >>> abstraction layer that would allow both NoSQL as well as SQL data >>> stores to be used. Unfortunately, it seems that this patch >>> removes the ability to use ReDIS, among other NoSQL stores. I >>> think this is a mistake, and although I like much of the code in >>> this patch, I was hoping that SQLAlchemy could be hidden behind an >>> abstraction layer that would play nicely with the non-relational >>> data stores. >>> >>> As this patch stands, we take a 180 degree turn away from NoSQL >>> data stores and back into the relatively comfortable norms of the >>> SQL databases. While there's nothing particularly wrong with SQL >>> databases (as you know, I'm a fan of many of them ;) ), I think >>> that keeping non-relational data store capabilities is pretty >>> critical. >>> >>> After an email discussion with SQLAlchemy's Michael Bayer about >>> SQLAlchemy's future with NoSQL data stores. Although there is an >>> issue in the SQLAlchemy trac system about this (see here: >>> http://www.sqlalchemy.org/trac/ticket/1518) the likelihood of this >>> module seeing the light of day is unlikely in the next year or >>> two. >>> >>> So...what to do? There are at least four options I can see: >>> >>> 1) Go forward with this patch and add NoSQL stores back at some >>> later time by ourselves 2) Go forward with this patch and wait >>> until SQLAlchemy properly supports key value stores 3) Delay this >>> patch until after the Austin release and have a larger discussion >>> about it here and at the next summit 4) Go back to the drawing >>> board and try again with a less ambitious set of patches that >>> incrementally changes the way the data stores work. >>> >>> I'm personally on the fence. I'd prefer to at least delay the >>> patch until after Austin, but I understand there are now at least 4 >>> branches that depend on this one, which makes things, well, a bit >>> difficult. >>> >>> -jay >>> >>> On Tue, Aug 31, 2010 at 8:46 PM, Vishvananda Ishaya >>> <vishvananda@xxxxxxxxx> wrote: >>>> I've proposed a merge of the orm refactor branch that a large >>>> part of the nasa/anso team has been working on. I'm hoping >>>> everyone can pick it apart and we end up with a really clean >>>> system that everyone likes. I've copied the description of the >>>> change and issues below. If the mailing list debates get too >>>> complicated, we should just organize a time to discuss it in >>>> IRC. >>>> >>>> Proposing merge to get feedback on orm refactoring. I am very >>>> interested in feedback to all of these changes. >>>> >>>> This is a huge set of changes, that touches almost all of the >>>> files. I'm sure I have broken quite a bit, but better to take the >>>> plunge now than to postpone this until later. The idea is to >>>> allow for pluggable backends throughout the code. >>>> >>>> Brief Overview For compute/volume/network, there are multiple >>>> classes service - responsible for rpc this currently uses the >>>> existing cast and call in rpc.py and a little bit of magic to >>>> call public methods on the manager class. each service also >>>> reports its state into the database every 10 seconds manager - >>>> responsible for managing respective object classes all the >>>> business logic for the classes go here db (db_driver) - >>>> responsible for abstracting database access driver >>>> (domain_driver) - responsible for executing actual shell commands >>>> and implementation >>>> >>>> Compute hasn't been fully cleaned up, but to get an idea of how >>>> it works, take a look at volume and network >>>> >>>> Known issues/Things to be done: >>>> >>>> * nova-api accesses db objects directly It seems cleaner to have >>>> only the managers dealing with their respective objects. This >>>> would mean code for 'run_instances' would move into the manager >>>> class and it would do the initial setup and cast out to the >>>> remote service >>>> >>>> * db code uses flat methods to define its interface In my mind >>>> this is a little prettier as an abstract base class, but driver >>>> loading code can load a module or a class. It works, so I'm not >>>> sure it needs to be changed but feel free to debate it. >>>> >>>> * Service classes have no code in them Not sure if this is a >>>> problem for people, but the magic of calling the manager's >>>> methods is done in the base class. We could remove the magic from >>>> the base class and explicitly wrap methods that we want to make >>>> available via rpc if this seems nasty. >>>> >>>> * AuthManager Projects/Users/Roles are not integrated into this >>>> system. In order for everything to live happily in the backend, >>>> we need some type of adaptor for LDAP >>>> >>>> * Context is not passed properly across rabbit Context should >>>> probably be changed to a simple dictionary so that it can be >>>> passed properly through the queue >>>> >>>> * No authorization checks on access to objects We need to decide >>>> on which layer auth checks should happen. >>>> >>>> * Some of the methods in ComputeManager need to be moved into >>>> other layers/managers * Compute driver layer should be abstracted >>>> more cleanly * Flat networking is untested and may need to be >>>> reworked * Some of the api commands are not working yet * Nova >>>> Swift Authentication needs to be refactored(Todd is working on >>>> this) >>>> >>>> _______________________________________________ Mailing list: >>>> https://launchpad.net/~nova Post to : >>>> nova@xxxxxxxxxxxxxxxxxxx Unsubscribe : >>>> https://launchpad.net/~nova More help : >>>> https://help.launchpad.net/ListHelp >>>> >>>> >> >> >> _______________________________________________ Mailing list: >> https://launchpad.net/~nova Post to : nova@xxxxxxxxxxxxxxxxxxx >> Unsubscribe : https://launchpad.net/~nova More help : >> https://help.launchpad.net/ListHelp > >
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