enforce-mandatory-tags.sentinel

# Imports mock data
import "tfplan/v2" as tfplan

# Get all AWS instances from all modules
ec2_instances = filter tfplan.resource_changes as _, rc {
    rc.type is "aws_instance" and
        (rc.change.actions contains "create" or rc.change.actions is ["update"])
}

# Mandatory Instance Tags
mandatory_tags = [
    "Name",
    "Owner",
    "Environment",
]

# Allowed Types
allowed_types = [
    "t2.micro",
    "t2.small",
    "t2.medium",
]

# Rule to enforce tags on all instances
mandatory_instance_tags = rule {
    all ec2_instances as _, instance {
        all mandatory_tags as mt {
            instance.change.after.tags contains mt
        }
    }
}

# Rule to restrict instance types
instance_type_allowed = rule {
    all ec2_instances as _, instance {
        instance.change.after.instance_type in allowed_types
    }
}

# Main rule that requires other rules to be true
main = rule {
    (instance_type_allowed and mandatory_instance_tags) else true
}