HCL2 temporary iterator variable interpolation?

Nomad
1

Hey folks :wave:

I am having some trouble figuring out when and where I can use interpolation of the temporary iterator variable in dynamic blocks.

I want to utilize dynamic blocks in order to automagically generate task groups and task definitions. Take a look at the job below - essentially I need to provide the current value of the temporary iterator variable as an argument to the Docker container but no matter what I have tried I have been unsuccessful so far :frowning:

It works fine here :

labels   = ["prom-exporter-${ip.value}"]

but this simply refuses to interpret the variable ${ip.value}:

   ...
	config {
	  image = "quay.io/citrix/citrix-adc-metrics-exporter:1.4.6"
	  args = [
	    "--target-nsip=${ip.value}",
	    "--port=${NOMAD_PORT_http}"
	  ]
   ...

nomad validate and nomad plan both accept the job without any complaints but interpolation does not happen as the container literally receives --target-nsip=${ip.value} as it’s input :confused:

The full jobfile :

variables {
  netscaler_endpoints = ["1.2.3.4", "4.5.6.7", "8.9.10.11"]
}

job "netscaler-prometheus" {
  datacenters = ["dc1"]
  namespace = "whatever"

  constraint {
    attribute = "${attr.nomad.version}"
    operator  = "semver"
    value     = ">= 1.0.0"    
  }
  
  dynamic "group" {
    for_each = var.netscaler_endpoints
    iterator = ip
    labels   = ["prom-exporter-${ip.value}"]

    content {
      
      network {
        port "http" {}

        dns {
          servers = ["10.10.10.10"]
        }
      }

      task "prom-exporter" {
       driver = "docker"	

	config {
	  image = "quay.io/citrix/citrix-adc-metrics-exporter:1.4.6"
	  args = [
	    "--target-nsip=${ip.value}",
	    "--port=${NOMAD_PORT_http}"
	  ]
      ports = ["http"]
	}

	service {
	  name = "prom-exporter"
	  port = "http" 
	  
	    check {
	      type     = "http"
          port     = "http"
	      path     = "/"
	      interval = "5s"
	      timeout  = "3s"
          }
         }
	
        resources {
          cpu    = 500
          memory = 256
        }
	
      } # task ends here
    } # content block ends here
  } # dynamic block ends here
} # job ends here
2

Hi @henrikjohansen! It looks like you’ve just run into nomad/#9871. I’ll drop your example in that issue as well, for our investigation.

3

Hey @tgross :wave: Thanks for letting me know - I’ll keep an eye on the GH issue :+1: