Another question: After creating subnets my functions returns []*ec2.Subnet, but in ElasticBeanstalk I need to add them to EnvironmentSettingArray with EnvironmentSettingArgs {Name: pulumi.String("Subnets"), NampeSpace: pulumi.String("aws:ec2:vpc"), Value: pulumi.String("subnetid1,subnetid2,subnetid3")} However how can I create a comma seperated string from the array, as when I do fmt.Sprintf("%v,%v,%v",subnet[0].ID(),subnet[1].ID(),subnet[2].ID()) I only get the pointers, not the real value as this is filled at deployment time and not after creation.

you likely want

pulumi.Sprintf

which works similarly to

fmt.Sprintf

but knows to wait for outputs to resolve before formatting the string - See https://www.pulumi.com/docs/intro/concepts/programming-model/#outputs-and-strings

How could I have missed this, thanks for the help. It worked.