String interpolation with function call not working for meta properties

[TylerPachal]

Nomad version

0.12.9

Issue

String interpolation with function call not working for meta properties.

I have two places in my .hcl file where I am using the substr function to grab the short version of my commit hash, which is used to tag my docker image. In the meta stanza, the string is not interpolated, and as show as-is in the UI (see the screenshot). In the task/config stanza, it works fine.

Job file

job "my-job" {
  
  meta { 
    image_tag = "${substr("[[ .DEPLOY_SUB___VERSION ]]", 0, 7)}"           # This doesn't work, and is show in the UI as-is
  }

  group "my-group" {
    task "my-task" {
      config {
        image = "uri.for.my.image:${substr("[[ .DEPLOY_SUB___VERSION ]]", 0, 7)}"       # This works
      }
    }
  }

  # ...
} 

This is what is presented in the UI:

I also tried doing the following, but it was invalid hcl:

image_tag = substr("[[ .DEPLOY_SUB___VERSION ]]", 0, 7)

---

Edit: We are using Levant to do the replacement of DEPLOY_SUB___VERSION.

[tgross]

@TylerPachal the HCL2 functions like substr are only available in Nomad 1.0 and above, so Nomad is trying that as a plain old string. Even for Nomad 1.0 the syntax needs to be a little different because of a bug in quote-escaping (ref #9838), but this job works:

job "example" {
  datacenters = ["dc1"]

  meta {
    tag = substr("SOMEVALUE", 0, 7)
  }

  group "cache" {
    network {
      port "db" {
        to = 6379
      }
    }

    task "redis" {
      driver = "docker"

      config {
        image = "redis:3.2"

        ports = ["db"]
      }

      resources {
        cpu    = 500
        memory = 256
      }
    }
  }
}

$ nomad job run ./example.nomad
==> Monitoring evaluation "2e7c51eb"
    Evaluation triggered by job "example"
    Allocation "5108edaf" created: node "5005e621", group "cache"
==> Monitoring evaluation "2e7c51eb"
    Evaluation within deployment: "88bcb501"
    Evaluation status changed: "pending" -> "complete"
==> Evaluation "2e7c51eb" finished with status "complete"

$ nomad alloc exec 5108 env | grep META
NOMAD_META_TAG=SOMEVAL
NOMAD_META_tag=SOMEVAL

[tgross]

Even for Nomad 1.0 the syntax needs to be a little different because of a bug in quote-escaping (ref #9838), but this job works:

Looks like #9838 was the wrong bug, as this works in master now. But looks like this is safe to close.

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