Minio client and extra initialization options

[stephank]

This adds mc to the profile if minio is enabled, and configures it to connect to the local minio using the conventional local alias.

I added services.minio.clientConfig = null as an opt-out. I imagine configuring other endpoints via Nix isn't ideal, because the config contains credentials, so this provides a way out to using your regular user config.

I also added a after option to allow running some additional initialization following minio startup.

[domenkozar]

Nice! I'd ask you to add an example/minio/ and example/minio/.test.sh to test the basics here as this service is getting more complex and it's good to have regression tests.

[domenkozar]

You can test it like:

$ devenv shell
$ devenv-test-example minio

[stephank]

Looks like devenv shell at the toplevel tries to rebuild nix itself for me, there's no cache. But I managed to write a test without it.

[stephank]

It looks like minio doesn't actually generate credentials when left empty, it just uses minioadmin:minioadmin, so I made options reflect that, and that makes it work without configuring credentials at all.

[domenkozar]

I've pushed a fix for making timeout available for tests, could you rebase?

[stephank]

Failure was because of default = defaultClientConfig; on an option, but that value was derived from config that was not available if minio is disabled.

I now use mkBefore, so that you could add aliases with just services.minio.clientConfig.aliases.foo = { ... }, and so that version is also set in that case. But unlike mkDefault, that means simply clientConfig = null doesn't work anymore, and mkForce is required.