On `trusty` there is no package for `boto` or `gevent` on Python 3, both
of which are dependencies of `wal-e` (at the version we've pinned.) This
is something used only on database servers and only in a replication
scenario, and it doesn't involve any of our code outside the wal-e repo,
so the Python version it uses is quite independent of the Zulip
application server itself and the rest of our code. For now, keep it
explicitly on Python 2 while we move forward for most everything else.
This is only actually used in our `wal-e` setup, which is in
zulip_ops::postgres_common. (In fact the only mentions of `gevent` in
our whole Git history are for `wal-e`.) So remove where we mention it
on the broader zulip::postgres_common module, and move it where it's
needed.
This follows up on 98cef0ab4 by eliminating the only dependency
outside of the `zulip_ops` Puppet tree on a system Python-library
package which isn't available in `trusty` for Python 3.
In some of these contexts, we may still be *using* the Python 2
version, but at least this should eliminate running into
`ImportError`s one by one in scripts that run outside a virtualenv,
as we update their shebangs to refer to Python 3.
Several Python libraries we use don't come in Python 3 versions on
trusty: gevent, boto, twisted, django, django-tagging, whisper.
The latter two don't come in Python 3 versions even on xenial.
So some work required before we can actually switch the code that
relies on those libraries to run as Python 3 -- probably the best
solution will be to backport them all in our apt repo. (All but
`whisper` are packaged in zesty; `whisper` upstream just grew Python 3
support this year.)
The old "zulip_internal" name was from back when Zulip, Inc. had two
distributions of Zulip, the enterprise distribution in puppet/zulip/
and the "internal" SAAS distribution in puppet/zulip_internal. I
think the name is a bit confusing in the new fully open-source Zulip
work, so we're replacing it with "zulip_ops". I don't think the new
name is perfect, but it's better.
In the following commits, we'll delete a bunch of pieces of Zulip,
Inc.'s infrastructure that don't exist anymore and thus are no longer
useful (e.g. the old Trac configuration), with the goal of cleaning
the repository of as much unnecessary content as possible.