Add Dockerfiles for stretch

[stuartpb]

This time, I'm not going to reflexively merge the PR without review 😉

[danielmewes]

Looks good to me. Thanks for the PR @stuartpb .

Do we need to submit a PR to the official Docker repo for these to become available @dalanmiller ?

[dalanmiller]

We sure do I believe. Thank you for this @stuartpb :D

[dalanmiller]

@stuartpb it looks like other providers aren't specifying the release name in their lists, I assume this means we would make it available across all releases not just jessie or stretch?

https://github.com/docker-library/official-images/blob/master/library/ghost

[dalanmiller]

@yosifkit should we continue to state jessie in our file over here? I see a lot of other projects not listing any specific Debian release.

https://github.com/docker-library/official-images/blob/master/library/rethinkdb

[yosifkit]

The jessie in the library file is just the folder where the Dockerfile exists in your repo. Are you wanting to do something like python where you have tags for other Linux flavors? I am not sure it makes sense for a service to need to be in different Linux flavors; the reason that python has a wheezy variant is that some users need to install old libraries that are only available there. The alpine variants are a push to create tiny images.

We updated our docs recently. We recommend keeping the number of versions to a minimum since it is what controls the "supported tags" list that is generated for the readme on Docker Hub, while old version will remain available to docker pull.

[stuartpb]

Yeah - the other distro variants in this repo are really just there for use by any end user to build from, in the event that they need their RethinkDB container to be running on a specific Debian/Ubuntu release for some particular edge case reason (like an affiliated dependency they need to run alongside it inside the container, like a debugger or something). They're mostly here just because upstream releases packages for them, and it's trivial to produce the corresponding Dockerfiles to provide those packages for containerization.

Ideally, the official Docker repo images would be based on Alpine Linux, per the official recommendations - would it be possible to get upstream @rethinkdb packaging RethinkDB on that platform (in which case we could publish Dockerfiles for it and switch the official images accordingly)?

[stuartpb]

Also, @yosifkit does the library policy now mean that only supported versions should be listed in the library file (meaning that we should push a PR to remove lines for older patch-releases)?

I'm pretty sure that's what this says, but I just want to double-check that I'm reading this right.

[stuartpb]

Separate from the Alpine-ization question, I've created a PR to remove RethinkDB's unsupported versions at docker-library/official-images#1650.