Open Stack

On 02/10/2015 10:28 AM, Alexander Tivelkov wrote:
> Hi folks,
> 
> One of the key features that we are adding to Glance with the
> introduction of Artifacts is the ability to have multiple versions of
> the same object in the repository: this gives us the possibility to
> query for the latest version of something, keep track on the changes
> history, and build various continuous delivery solutions on top of
> Artifact Repository.
> 
> We need to determine the format and rules we will use to define,
> increment and compare versions of artifacts in the repository. There
> are two alternatives we have to choose from, and we are seeking advice
> on this choice.
> 
> First, there is Semantic Versioning specification, available at [1].
> It is a very generic spec, widely used and adopted in many areas of
> software development. It is quite straightforward: 3 mandatory numeric
> components for version number, plus optional string labels for
> pre-release versions and build metadata.
> 
> And then there is PEP-440 spec, which is a "recommended approach to
> identifying versions and specifying dependencies when distributing
> Python". It is a "pythonic" way to set versions of python packages,
> including PIP version strings.
> 
> Conceptually PEP-440 and Semantic Versioning are similar in purpose,
> but slightly different in syntax. Notably, the count of version number
> components and rules of version precedence resolution differ between
> PEP-440 and SemVer. Unfortunately, the two version string formats are
> not compatible, so we have to choose one or the other.
> 
> According to my initial vision, the Artifact Repository should be as
> generic as possible in terms of potential adoption. The artifacts were
> never supposed to be python packages only, and even the projects which
> will create and use these artifacts are not mandatory limited to be
> pythonic, the developers of that projects may not be python
> developers! So, I'd really wanted to avoid any python-specific
> notations, such as PEP-440 for artifacts.
> 
> I've put this vision into a spec [3] which also contains a proposal on
> how to convert the semver-compatible version strings into the
> comparable values which may be mapped to database types, so a database
> table may be queried, ordered and filtered by the object version.
> 
> So, we need some feedback on this topic. Would you prefer artifacts to
> be versioned with SemVer or with PEP-440 notation? Are you interested
> in having some generic utility which will map versions (in either
> format) to database columns? If so, which version format would you
> prefer?
> 
> We are on a tight schedule here, as we want to begin landing
> artifact-related code soon. So, I would appreciate your feedback
> during this week: here in the ML or in the comments to [3] review.

Because you should have more things to look at:

http://docs.openstack.org/developer/pbr/semver.html

We've already done some work to try to reconcile the world of semver
with the world of PEP440 over in PBR land.