Tag hierarchies

[eproxus]

Some way to support a custom tag hierarchy. For example:

aws-name-server --tag-hierarchy Name,Role,Env ...

This would allow names like:

• <name>.<role>.<env>.aws.example.com -> skywalker.app.staging.aws.example.com

There are probably many edge cases in supporting such a structure. E.g. what to do with missing tags?, how to access the <n> component of higher levels?

[ConradIrwin]

Hi @eproxus, This sounds like a very complicated way of doing things so I'd like to understand your setup a bit more.

Do you re-use name tags per-role per-env, or just per-env?

[eproxus]

Per env, primarily.

[eproxus]

Actually, I would be perfectly fine if I could throw in Env as the top layer. Like 1.db.dev.aws.example.com.

[ConradIrwin]

I guess there are a couple of different ways we could try and do this, I think my favourite is:

./aws-name-server --namespace-tag env --domain aws.bugsnag.com

That said, I think this feature ties in strongly with the idea of serving custom tags (not just name/role), so it might be nice if we can find a solution that ties in with that too.

Maybe something like this, but with nicer syntax:

./aws-name-server --serve +Name.aws.bugsnag.com \
                  --serve +Role.role.aws.bugsnag.com \
                  --serve +Role.+Env.aws.bugsnag.com

That also introduces the edge case of "what to do with a machine with no Env tag"?

I'm always worried that too much configuration will just make it hard to use. I guess we can just keep --domain aws.bugsnag.com as the "quick start" and then have an "advanced usage" section too.

Any thoughts?

[eproxus]

I like the last version, it is a better generalization from my first proposal. I guess one route would only server the machines that match (i.e. that have values for all tags in that route)?

Agree, --domain $DOMAIN would be shorthand for --serve +Name.$DOMAIN --serve +Role.role.$DOMAIN. Another version could be that just --domain $DOMAIN would by default serve the +Name and +Role.role prefixes if no --serve flags existed, otherwise serve what was specified?

What about collisions? If you do --server +Name.$DOMAIN --server +Name.+Env.$DOMAIN, what happens when you have Name=test and Env=test?