-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 11.04.2009 19:32 Uhr, Tres Seaver wrote:
Hanno Schlichting wrote:
Chris Withers wrote:
Dieter Maurer wrote:
Tres has earlier proposed a meta egg to represent "versions.cfg" in a setuptools only (non buildout) environment.
A meta egg is an egg that only list dependencies and does not contain code of its own. Indeed, so we'd need 2 eggs for Zope 2 :-(
Something I bumped into recently:
If the Zope 2 egg actually hard-specifies its dependencies, how do I upgrade any of those dependencies to newer versions that fix bugs i may have encountered/fixed? You roll your own meta egg. You cannot override hard version specifications inside a setup.py.
In all other debates we seemed to agree on not over specifying requirements in setup.py files, I wonder why anybody still tries to follow this route.
Maybe because it makes for a predictable / reproducible installation? After all, the 2.12a1 egg already released is now broken under easy_isntall becasse it *doesn't* nail down its dependencies.
Predicatbility requires one of the following:
- Run an index, and make people install from there rather than PyPI; at that point, you are a "distribution" maintainer, and can ensure consistency. Users who trust you can "safely" upgrade at will, because you are responsible for ensuring that the eggs in the index work together.
- Release a nailed-down egg (or the equivalent buildout.cfg / versions.cfg, and let people install from PyPI. Upgrades are not really safe: you won't get borked by newly released eggs, but removed / re-uploaded eggs can still hose you.
- Release some kind of monolith, generated from the same metadata as above. Upgrades aren't really possible here: you have to release a new version of the monolith.
Let's see what other people who want to support easy_install do: They require you to use virtualenv and create a links page, which has all the dependencies in all the required versions on it:
http://pylonshq.com/download/0.9.7/ http://www.turbogears.org/2.0/downloads/2.0final/ http://dist.repoze.org/zope2/dev/ http://dist.plone.org/release/3.3rc2/
In order to install from on of these you do for example:
easy_install -f http://pylonshq.com/download/0.9.7 Pylons
You want '-i' and the index URL, not '-f' and the "directory-containing- tarballs" URL.
and that's it. Some projects package up the multiple steps (including installing setuptools) into a little helper script.
As you might notice all that is required is a known URL and Apache serving a bunch of files directly.
Without supplying the '-i' ('--index-url') flag, you are still subject to the variability of PyPI.
A dedicated index is a clean solution (I have not figure out or understand how this is accomplished for Zope 3). Another low hanging fruit is releasing Zope 2 as 2 packages (one with unpinned versions (for buildout) and one with fully pinned versions). I am trying out this approach for the next a2 release. Andreas -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (Darwin) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAkniFb8ACgkQCJIWIbr9KYwKWACdEa+VpOliCYnd8M1BLvVFJyHe 70wAoM8XlOrP7PBY0Bxqpf5Lev4GHVSh =FBm9 -----END PGP SIGNATURE-----