Don't use dots in environment variables

[tomzo]

Most environment variables currently are in form of GOCD_CLI.VALUE. This is very inconvenient for unix shells where . is simply not allowed in environment variable name.
This leads to bad user experience:

$ export GOCDCLI_AUTH.TYPE=basic
bash: export: `GOCDCLI_AUTH.TYPE=basic': not a valid identifier

It would suffice to use underscores, e.g. GOCDCLI_AUTH_TYPE

[marques-work]

@tomzo hmm, this is a built-in feature of spf13/viper, which we are using to help manage configuration. We might need to build our own support to change this behavior.

[marques-work]

@tomzo Looks like we can hook into this: https://github.com/spf13/viper/blob/7a605a50e69cd1ea431c4a1e6eebe9b287ef6de4/viper.go#L1118-L1124

[tomzo]

@marques-work how about key delimiter here ?

[arvindsv]

They have some docs about using environment variables: https://github.com/spf13/viper#working-with-environment-variables

I don't know enough about this to know if it's relevant.

[marques-work]

@tomzo Unfortunately, that's not an exported member, so we cannot set it; I didn't see a setter for it anywhere, but I may have missed it.

@arvindsv I think you can use BindEnv() to associate custom keys with settings. That could probably work also. I was really hoping that the StringReplacer would let us specify how env variable names are calculated and thus get env variable support for free with no further maintenance. But we'll see how that works out :)