nginx package signature guarantees with Xenial?

[Jeff Kaufman]

I work on ngx_pagespeed, which is an open source nginx module that
rewrites web pages so they load faster.  To install ngx_pagespeed on
Ubuntu site-owners currently need to build our package from source,
but they would find it much easier if we could ship binary packages
that they could install.  Nginx didn't previously support these
packages, but they added it recently and Xenial is the first release
of Ubuntu that includes a recent enough version of nginx to make this
possible.

Nginx dynamic modules are pretty different from Apache ones, or other
ones that go via an ABI.  Instead of a defined interface they use a
very inclusive signature, and require modules to have been compiled
against a copy of nginx that has the same signature as the host.
Would you be up for committing not to make changes to the signature of
nginx in a release, over the course of the several years of
maintaining it?  If so we could release one module compiled for
"Ubuntu 16 LTS" and then in two years start maintaining an additional
module compiled against "Ubuntu 18 LTS".  Otherwise I'm not sure how
to ship binary modules for Ubuntu.

(One thing that this would mean would be not updating the version of
nginx that's included in a release, since that's part of the
signature.  Switching from 1.9.15 to 1.10.0, which you did right after
releasing, is the sort of thing this would preclude.)

Jeff Kaufman
PageSpeed Team, Google