I just realized that both of these points only apply to version 9.3. What's the correct approach (I'm thinking about the template) to use the ossp-uuid lib on 9.3 and --with-uuid=e2fs on 9.4+ ?

Can you elaborate on what the benefits of doing this might be? This isn't something that's done for the Debian packages (https://sources.debian.net/src/postgresql-9.6/9.6.1-2/debian/rules/#L74), which is where our ./configure flags came from (since we're trying to emulate upstream's own released packages as closely as possible), so I'm pretty strongly -1 at a first glance, but could be convinced (strongest argument would be an explicit recommendation from upstream that this is preferred).

This is only for version 9.3. The uuid-ossp extension isn't installed on the 9.3-alpine flavor of this image but it's there for all the other versions.

9.4-alpine:

docker run -t -i --rm  postgres:9.4-alpine bash -c 'ls /usr/local/share/postgresql/extension/uuid*'
/usr/local/share/postgresql/extension/uuid-ossp--1.0.sql
/usr/local/share/postgresql/extension/uuid-ossp--unpackaged--1.0.sql
/usr/local/share/postgresql/extension/uuid-ossp.control

9.3-alpine:

docker run -t -i --rm  postgres:9.3-alpine bash -c 'ls /usr/local/share/postgresql/extension/uuid*'
ls: /usr/local/share/postgresql/extension/uuid*: No such file or directory

The flag --with-uuid is only valid for 9.4+, for 9.3 you have to use --with-ossp-uuid and you need the ossp-uuid library.

Ah! Grabbing http://apt.postgresql.org/pub/repos/apt/pool/main/p/postgresql-9.3/postgresql-9.3_9.3.15-1.pgdg80%2b1.debian.tar.xz and looking at debian/rules:

  --mandir=/usr/share/postgresql/$(MAJOR_VER)/man \
  --docdir=/usr/share/doc/postgresql-doc-$(MAJOR_VER) \
  --sysconfdir=/etc/postgresql-common \
  --datarootdir=/usr/share/ \
  --datadir=/usr/share/postgresql/$(MAJOR_VER) \
  --bindir=/usr/lib/postgresql/$(MAJOR_VER)/bin \
  --libdir=/usr/lib/$(DEB_HOST_MULTIARCH)/ \
  --libexecdir=/usr/lib/postgresql/ \
  --includedir=/usr/include/postgresql/ \
  --enable-nls \
  --enable-integer-datetimes \
  --enable-thread-safety \
  --enable-debug \
  --disable-rpath \
  --with-ossp-uuid \
  --with-gnu-ld \
  --with-pgport=5432 \
  --with-system-tzdata=/usr/share/zoneinfo \

And over in debian/control:

Build-Depends: ...
...
 libossp-uuid-dev,
...

Alpine digging leads to https://bugs.alpinelinux.org/issues/4832, http://git.alpinelinux.org/cgit/aports/commit/?id=13925b3651ff86ea00c3864814eb83e0fb0862b3, and https://patchwork.alpinelinux.org/patch/933/, none of which really help shrink this 9.3-specific delta any. 😞

Technically, --with-ossp-uuid could be used for all versions, it's an alias for --with-uuid=ossp on 9.4+.
On 9.4+ the build process looks for uuid_generate instead of uuid_export if it's not ossp-uuid , that's the reason why you can use other uuid libraries. 😕

Clicked on the wrong button. 😑

It actually also applies to 9.2.

I modified the update script to add ossp-uuid to the 9.2 and 9.3 alpine images and also to remove the --enable-tap-tests flag. It removes the unused placeholders and uses --with-uuid=e2fs for 9.4+. Let me know if I missed something.

We're running a custom 9.3-alpine image because of this issue, it would be nice if we could drop it and just use the official one. 🙂

Thanks for your patience -- I rebased and added a minor commit, and I suppose this will do for now (sad that we can't remove the disparity until Oct 2018 when 9.3 is EOL, but oh well). 👍 ❤️

(Will merge as soon as Travis is green as one final smoke test)