Use vault or not (conditionnal)

Hi,

I have a gitlab projet for packer that build VM on vpshere. I use vault to store the password :

    username            = var.vsphere_username
    password            = vault(var.vsphere_password_vpath, "current_password")

But, If someone clone the projet and build himself, I don’t want to use this password. I want it “changes” to:

    username     = {{ env `USER` }}
    password      = {{ env `DOMAIN_PASS` }}  # or somethings else

How can I build this condition in packer hcl ?