Add docker image creation

[Aloz1]

It would be advantageous for several reasons (security, dev-ops deploy-ability, environment segregation), to have git-as-svn running inside docker.

I've been playing around with docker and gradle to generate a docker image. I've got it to the point where I think it would be useful for others, although I'd still consider it a WIP for now.

[Aloz1]

Also, I'm not super familiar with gradle (I don't usually dabble in java or kotlin that much), so I'm not convinced the targets are as nice as they could be. Using 'Exec::class' to invoke 'sh' just to allow docker to pipe to bzip2 feels hacky, but it seems to work well. Surely there's a more idiomatic way of doing that in gradle???

[Aloz1]

Also, at the moment, it just uses 'config.yml' as a default when it sets up its environment. I'm thinking it might be nice if there was a "GAS_CONFIG_TEMPLATE" env variable that the container could use to choose the config file to spit out if there isn't one already there. It won't make a difference 99% of the time, but would make setup marginally more convenient if someone's setting up git-as-svn for the first time.

[slonopotamus]

I'm not sure I am ready to support this. Such dockerfile almost fully duplicates the logic from git-as-svn debian packaging.

[Aloz1]

Hm. There's certainly somewhat of a "duplicated" effort here from the fact that the docker image is based on Alpine instead of Debian. I might play around with reworking this to be a Debian based image instead, meaning it can make use of the already generated .deb file.

I might also see what I can do about the duplicated "config.yml". I wasn't totally happy with that myself.

[slonopotamus]

Also: it is very likely that whoever uses it would want to make modifications to config file.

Additional thoughts: most of git-as-svn users that I am aware of, use git-as-svn combined with GitLab. Unfortunately, they bneed to be in the same process space because git-as-svn invokes GitLab pre-push hooks. This docker image cannot be used for that.

[slonopotamus]

it can make use of the already generated .deb file

Yep, this might end up as a more manageable construction.

[Aloz1]

Also: it is very likely that whoever uses it would want to make modifications to config file.

Yep, that should be possible as is. I guess I should also put together some documentation on how one would setup git-as-svn in docker.

Additional thoughts: most of git-as-svn users that I am aware of, use git-as-svn combined with GitLab. Unfortunately, they bneed to be in the same process space because git-as-svn invokes GitLab pre-push hooks. This docker image cannot be used for that.

Ah, good to know. I'll work out how this is gonna integrate with the dockerised gitlab. I must admit, I've only tested this against gitea for now.