Shared variables with multiple variable files

[boro2g]

Is your proposal related to a problem?

As per discussion with TimL, in our project we're using a SOPS encoded variables file for secrets, but would also like to benefit from shared (non-secret) values we can apply to multiple components.

Examples would be things like common urls which need to be available in multiple components. One hackfix is to add a new component which exposes all the shared variables, which then exposes each as an output

Some gotchas

• which value takes priority if variables clash

[mvantellingen]

I see no reason to not support multiple variable files.
E.g.: mach-composer apply --var-file=config1.yml --var-file=config2.yml