How about making this conditional so we aren't opening up a port they aren't using?

unless i group both of them in another layer of module, it seems like terraform doesn't like references to conditional modules, i get this error when have 2 conditional rds_security_group

Error: Unsupported attribute

  on ../../modules/database/main.tf line 105, in module "rds_postgres":
 105:   vpc_security_group_ids = ["${module.rds_security_group_postgres.this_security_group_id}"]

This value does not have any attributes.


Error: Unsupported attribute

  on ../../modules/database/main.tf line 155, in module "rds_mysql":
 155:   vpc_security_group_ids = [module.rds_security_group_mysql.this_security_group_id]

This value does not have any attributes.

How about just having a single group but changing the rule depending on which db is chosen?

like this? 457fdc9#diff-fc95e87f6973cfeeb3e12756fd64f5d5L10-L25

yeah this seems to work, not sure if it's a little harder to read though

If we add another type of DB the ternary operator wouldn't work and we'd have to switch to a lookup or something which might be cleaner, but for now it should be fine.

Should be "engine" or just "which database", not "driver"