Global environment variables

[adamshand]

Is your feature request related to a problem? Please describe.

There are some settings which many applications require and currently must be configured individually for each app.

A good example of this is email settings (SMTP hostname, port, TLS, user, pass etc).

Describe the solution you'd like

If there was a way to define global environment variables, one-click-apps could make use of this to make installation & configuration of apps easier and more foolproof.

[githubsaturn]

I think rather than global "env variables", we need to create global "variables" which the env vars can be set to.

This is to support a use case where you might have SMTP_PROD vs SMTP_STAGING.

[adamshand]

Even better!

[adamshand]

It would also be helpful if this page showed all the built in variables that can be used in templates.

[itxtoledo]

We need also a way to select which global variables we need to use use in each service

[iamogre]

This would be very helpful