I've drafted the documentation for how this could be explained to
users. This may be easier to grok than the email:
https://github.com/apache/brooklyn-docs/pull/198/files#diff-21dacc664dfe4d0a156d65d768a0f0e2R28
Best
Alex
On 19/06/2017 17:39, Alex Heneveld wrote:
Hi All-
TL;DR - I am proposing that we encourage versions in Brooklyn of the
form "1.1.0" or "1.2-qualifier" such as "1.2-SNAPSHOT", silently
mapping when needed to OSGi as "1.1.0" or "1.2.0.qualifier" /
"1.2.0.SNAPSHOT"
Further to my last mail -- we have a bit of discord between various
versioning schemes--
* GitHub SemVer - which everyone talks lovingly about (though often
not knowledgeably, and it's stricter than I realized!)
* OSGi versioning - a precursor to (1), in widespread use but I've
never heard anyone say anything nice about it
* Maven - allows whatever you want but has recommendations and
conventions most people kinda follow
They all agree on up to three numbers at the start. It's what comes
after that varies, usually either a "-" (semver, maven, conventions)
or "." (osgi), followed by qualifiers. If practice almost everyone
seems to do "-" followed by qualifiers -- however qualifiers in
practice often don't follow the strict constraints of semver (no
leading zeroes, no underscores) nor some of the maven recommendations
(use of build number).
(Detailed summary on SemVer and OSGi versioning is included below for
reference.)
So far, Brooklyn hasn't had an opinion and I liked it that way.
However when registering OSGi bundles we MUST confirm with OSGi
versioning there. I'm pretty sure it's NOT desirable to enforce OSGi
versioning on types, given that few people use it. BUT we are moving
to a world where I think we want type versions (entity versions etc)
to align with bundle versions: there is really no point in types
having different versions to their defining bundle! This makes for an
incompatibility between what people would naturally use and what we
have to use within OSGi.
With examples, my assumption is that people want to use and see
strings like "1.1-SNAPSHOT". But under the covers the OSGi bundle
needs to have "1.1.0.SNAPSHOT".
I propose we resolve this by recommending a version syntax which fits
what most things people are doing and which is bi-di mappable to
OSGi. We use this version everywhere except where a strict OSGi
version is needed. We WARN if we get a non-compliant version in a
place which might be ambiguous. And we minimise places where we need
to rely on mapping. (The main place a mapping is needed is if we need
to create an OSGi version or compare with an OSGi version.)
Specifically I propose that Brooklyn type versions SHOULD be:
<major> ( "." <minor> ( "." <patch> ")? )? ( "-" <qualifier>) ?
where qualifier can have letters, numbers, "-" or "_" but NOT
additional ".".
We construct an OSGi version, when needed, by replacing the first "-"
with "." and inserting 0's if needed for a missing minor/patch. So
"1.1-SNAPSHOT" becomes "1.1.0.SNAPSHOT" when an OSGi version is needed.
Note that the above is a SHOULD. The only strict requirement is the
version string MUST NOT contain a ":". (That breaks parsing.)
Where non-compliant versions are supplied, we WARN, but things work.
We apply simple heuristics to create a valid OSGi version -- but the
problem is that we can no longer guarantee uniqueness ("0.0.0-a" and
"0.0.0.a" would be conflated), and the result is possibly quite
different to the input (eg "v1" would become "0.0.0.v1"). For this
reason if given a non-compliant version string we WARN what the result
is and that the resulting OSGi version could conflict with similar but
not-identical version strings -- but things work fine unless someone
is trying to have different bundles for "0.0.0-a" and "0.0.0.a"!
(If version is taken from MANIFEST.MF we reverse map to find the
brooklyn type versions, by changing the ".<qualifier>" to
"-<qualifier>"; no warning is needed here however as there is no risk
of non-uniqueness.)
Returning to examples:
* If a user specifies "1.1-SNAPSHOT" that's what they will see
everywhere except deep within OSGi where they will see "1.1.0.SNAPSHOT"
* If a user includes a MANIFEST.MF they would have to use
"1.1.0.SNAPSHOT" syntax there; they should still use "1.1-SNAPSHOT" in
the catalog.bom (or "1.1.0-SNAPSHOT" would be fine too). If they use
"1.1.0.SNAPSHOT" in the catalog.bom things will work, but they will
get a warning, and "1.1.0-SNAPSHOT" is what will display in the UI.
If a different number or qualifier (eg "1.2.0-SNAPSHOT" or "1.1-beta")
is used, it will give an ERROR because the mapping will make an
inconsistent OSGi version.
I think the only other big options are to require OSGi everywhere
(user unfriendly, and bad for backwards compatibility) or completely
decouple OSGi bundle version from type versions (overly confusing).
So while I'm reluctant to get in to the "versions should look like
XXX" I think it's worth it to play nicely in OSGi and semver, and the
above I think is the simplest and best way (even if the technicalities
don't look so simple on first read!).
That said if there are version strings people want that aren't going
to be well-supported with this proposal, please shout now!
Best
Alex
APPENDIX - Comparison of SemVer and OSGi
GITHUB SEMVER - https://github.com/mojombo/semver/blob/master/semver.md
*<major> "." <minor> "." <patch> ( "-" <pre_release_id> )? ( "+"
<build_id> )?*
The first three parts are numbers.
Where <pre_release_id> and <build_id> are dot-separated tokens made up
of letters, digits, and "-".
Key things:
* numbers and and pre_release_id tokens must not consist of numbers
with leading zeros (e.g. "1.01" is not valid, nor is "1.0.0-01"; but
"1.0.0+01" is)
* "-" immediately after the patch indicates pre-release and special
precedence rules apply
* build-id metadata should be ignored when computing precedence
OSGI VERSIONING - https://www.osgi.org/release-4-version-4-3-download/
- sections 1.3.2 and 3.2.5
*<major> ( "." <minor> ( "." <micro> ( "." <qualifier> )? )? )?*
The first three parts are the same as semver, except leading zeros are
allowed.
<qualifier> consists of letters, numbers, "-", and "_".
SUMMARY OF DIFFERENCES
(1) OSGi allows abbreviating when there is no qualifier data (e.g.
"1.1") whereas semver doesn't (has to be "1.1.0")
(2) OSGi requires a dot before the qualifier, whereas semver uses "-"
or "+" depending on what the qualifier is meant for
(3) OSGi permits underscores but not dots; semver permits dots to
separate non-empty tokens
END
