Nomad: Variable interpolation does not work in the meta stanza

[brooms]

Nomad version

Nomad v0.10.0-rc1 (c49bf41779d2ee462f46e2f58328e58c51970a83)

Operating system and Environment details

Distribution: Ubuntu Xenial 16.04.6
Kernel Version: Linux 4.4.0-165-generic x86_64
Docker Version: 19.03.3, build a872fc2

Issue

It appears that variable interpolation (using either node attributes or runtime environment variables) does not work in the meta stanza. I'm not sure whether this is an intended feature or not, but the documentation does suggest variable interpolation should work in the meta stanza.

Moving the meta stanza under the task stanza still results in the same output.

Reproduction steps

1. Run the sample job
2. Perform a docker inspect on the running container to see env variable output

Job file

job "meta-stanza-test-job" {

  type = "service"
  datacenters = ["dc1"]

  meta {
    TEST_NUMBER = 1
    TEST_STRING = "string"
    # Interpolation here fails for both node attributes (e.g. ${node.datacenter}) and runtime environment variables
    TEST_INTERPOLATION = "${NOMAD_DC}-${NOMAD_JOB_NAME}"
  }

  group "meta-stanza-test-group" {

    task "meta-stanza-test-task" {

      env {
        TEST_NUMBER = "${NOMAD_META_TEST_NUMBER}"
        TEST_STRING = "${NOMAD_META_TEST_STRING}"
        TEST_INTERPOLATION = "${NOMAD_META_TEST_INTERPOLATION}"
        ENV_TEST_INTERPOLATION = "${NOMAD_DC}-${NOMAD_JOB_NAME}"
      }

      driver = "docker"

      config {
        image = "registry:latest"

        port_map {
          http = 5000
        }
      }

      resources {
        cpu    = 500
        memory = 512 

        network {
          mbits = 25

          port "http" {
          }
        }
      }
    }
  }
}

Job output

Running docker inspect <container_id> gives:

"Env": [
"ENV_TEST_INTERPOLATION=dc1-meta-stanza-test-job",
"NOMAD_ADDR_http=172.16.1.10:31850",
"NOMAD_ALLOC_DIR=/alloc",
"NOMAD_ALLOC_ID=9f4e46c2-a707-e96b-dd44-f7440111d984",
"NOMAD_ALLOC_INDEX=0",
"NOMAD_ALLOC_NAME=meta-stanza-test-job.meta-stanza-test-group[0]",
"NOMAD_CPU_LIMIT=500",
"NOMAD_DC=dc1",
"NOMAD_GROUP_NAME=meta-stanza-test-group",
"NOMAD_HOST_PORT_http=31850",
"NOMAD_IP_http=172.16.1.10",
"NOMAD_JOB_NAME=meta-stanza-test-job",
"NOMAD_MEMORY_LIMIT=512",
"NOMAD_META_TEST_INTERPOLATION=${NOMAD_DC}-${NOMAD_JOB_NAME}",
"NOMAD_META_TEST_NUMBER=1",
"NOMAD_META_TEST_STRING=string",
"NOMAD_NAMESPACE=default",
"NOMAD_PORT_http=5000",
"NOMAD_REGION=global",
"NOMAD_SECRETS_DIR=/secrets",
"NOMAD_TASK_DIR=/local",
"NOMAD_TASK_NAME=meta-stanza-test-task",
"TEST_INTERPOLATION=${NOMAD_DC}-${NOMAD_JOB_NAME}",
"TEST_NUMBER=1",
"TEST_STRING=string",
"PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
],

[langmartin]

This is correct, the meta stanza does not interpolate variables.

[djenriquez]

@langmartin verified, just saw this in 0.10.0. I'm confused by your comment, are you saying this is intended behaviors, or are you confirming the issue?
The problem we're seeing is trying to interpret node meta into consul service tags defined in the service stanza. This worked fine in Consul 0.9.6 and earlier. Given this worked before, this should be marked as regression.