Specify postgis versions in docker tags

[JacobHayes]

We have deployed databases that are on 9.3/2.1 (in process of migrating to 9.5/2.2) and don't want to upgrade developer databases until we have a clear migration path for deployed environments. Since these images aren't tagged with the postgis version we can't stay on 2.1 without vendoring the old dockerfile (which we'd rather not do).

9.x/2.1 combinations wouldn't necessarily need to be maintained, like 9.0 is now - tagged, but not updated.

[JacobHayes]

I don't think this is a PR sort of thing since the tags are handled outside this repo, otherwise I'd submit one. :)

[md5]

Since I'm using Docker Hub's automated builds, it's difficult for me to maintain multiple sets of tags. The other complication is the fact that there is no longer a 2.1 version of the postgis package on apt.postgresql.org, so it's no longer possible to build a 9.3-2.1 image unless you leave out that package (resulting in the userspace utilities being dropped).

I took a look at the build details on Docker Hub and it looks like you should be able to pull the last build of 9.3-2.1 like so:

$ docker pull mdillon/postgis@sha256:aff8d882c76395e7c76bd1910b130c601d4ca2984c900c1723a167b770fb19d8

[md5]

See #8 and http://www.postgresql.org/message-id/flat/CAG077fAyaOdrpqg46ah_8N6MhUR-pLP3b85aePgKwbO70FKuRw@mail.gmail.com#CAG077fAyaOdrpqg46ah_8N6MhUR-pLP3b85aePgKwbO70FKuRw@mail.gmail.com for some more background.

[JacobHayes]

Unfortunate how the userland package is managed. Thanks for the image/sha, that'll work great!

I'm haven't used the automated builds, but could there be Dockerfiles, with just FROM mdillon/postgis@sha256:{latest_built_sha} where that would point to the pre-2.2 image tags? That's basically what I plan to do internally.

[md5]

There could be Dockerfiles like that as automated builds, but I'd rather not maintain them myself. The problem is that if there are security updates for the postgres images, I won't be able to update the 2.1 images unless I have an alternate Dockerfile that removes the postgis package.

[JacobHayes]

I don't mean maintain them, simply to create them, have them tagged as 9.x-2.1 (maybe with a -deprecated or similar) and then they could be removed. There is currently a 9.0 image tag that won't be updated, these would be in the same boat.

Any way, thank you for your help, I'll go ahead and close this.