Open Stack

What about using openstack-common as a library instead of a preprocessor 'inclusion' system/copy code around system....??

Maybe its time for that to happen?

It always seemed sort of silly to me that files are being copied around to different projects like this, instead of referring to code in a common library package.

On 7/2/12 12:16 PM, "Andrew Bogott" <abogott at wikimedia.org> wrote:

    Having spent some time last week writing code for openstack-common,
and having spent yet more time trying to get those changes into Nova, I
think it would be useful to define some best practices when crossing the
boundary between common and other openstack projects.

Background:

     The openstack-common project is subject to a standard code-review
process (and, soon, will also have Jenkins testing gates.)  Sadly,
patches that are merged into openstack-common are essentially orphans.
Bringing those changes into actual use requires yet another step, a
'merge from common' patch where the code changes in common are copied
into a specific project (e.g. nova.)
     Merge-from-common patches are generated via an automated process.
Specific projects express dependencies on specific common components via
a config file, e.g. 'nova/openstack-common.conf'.  The actual file copy
is performed by 'openstack-common/update.py,' and its behavior is
governed by the appropriate openstack-common.conf file.

Questions:

     When should changes from common be merged into other projects?
     What should a 'merge-from-common' patch look like?
     What code-review standards should core committers observe when
reviewing merge-from-common patches?

Proposals:

I.      As soon as a patch drops into common, the patch author should
submit merge-from-common patches to all affected projects.
     A.  (This should really be done by a bot, but that's not going to
happen overnight)

II.     In the event that I. is not observed, merge-from-common patches
will contain bits from multiple precursor patches.  That is not only OK,
but encouraged.
     A.  Keeping projects in sync with common is important!
     B.  Asking producers of merge-from-common patches to understand the
full diff will discourage the generation of such merges.

III.    Merge-from-common patches should be the product of a single
unedited run of update.py.
     A.  If a merge-from-common patch breaks pep8 or a test in nova,
don't fix the patch; fix the code in common.

IV.    Merge-from-common patches are 'presumed justified'.  That means:
     A. Reviewers of merge-from-common patches should consider test
failures and pep8 breakages, and obvious functional problems.
     B. Reviewers of merge-from-common patches should not consider the
usefulness, design, etc. of merge-from-common patches.  Such concerns
need to be handled within the common review process.
     C. Merges from common should get reviewed early and approved
readily in order to avoid project divergence

V.     Changes to openstack-common.conf are a special case.
     A. Patches with openstack-common.conf changes should include the
relevant merge-from-common changes.
     B. Such patches should /not/ include any other merge-from-common
changes.
     C. Such patches should not only include the common merges, but
should also include whatever code changes make use of the new merge.
     D. Such patches require the same justification and scrutiny as any
other standard project patch.

Please discuss!  If we're able to reach general agreement about this
process, I will document the process in the openstack-common HACKING
guidelines.

-Andrew




On 7/2/12 11:38 AM, Russell Bryant (Code Review) wrote:
> I did that before seeing this patch.  However, I think I prefer what I pushed since it's individual updates explaining what they update instead of a blanket "update everything" commit.
>
>


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