gistfile1.txt

GET /v2/CALL_EXTERNAL|syntribos.extensions.identity.client:get_project_id_v3:["user"]|/os-hypervisors/{hypervisor_id:CALL_EXTERNAL|syntribos.extensions.nova.client:get_hypervisor_id:[]|} HTTP/1.1
Accept: application/json
X-Auth-Token: CALL_EXTERNAL|syntribos.extensions.identity.client:get_scoped_token_v3:["user"]|

Only other option I can think of that isn't a complete re-write (i.e. going to YAML) would be something like:

GET /v2/{tenant_id}/os-hypervisors/{hypervisor_id} HTTP/1.1
Accept: application/json
X-Auth-Token: {token}
========================
{
    "tenant_id": "identity:get_project_id_v3",
    "hypervisor_id": "nova:get_hypervisor_id",
    "token": "identity:get_scoped_token_v3"
}