Ansible nested loop

gistfile1.txt

- name: test
  hosts: localhost
  gather_facts: false

  vars:
    containers:
      grafana:
        variables:
          docker:
            foo1: "https://etcd/foo1"
            foo2: "https://etcd/foo2"
            foo3: "https://etcd/foo3"
            foo1s: "https://vault/foo1s"
            foo2s: "https://vault/foo2s"
            foo3s: "https://vault/foo3s"
      prometheus:
        variables:
          docker:
            foo4: "https://etcd/foo4"
            foo5: "https://etcd/foo5"
            foo6: "https://etcd/foo6"
            foo4s: "https://vault/foo4s"
            foo5s: "https://vault/foo5s"
            foo6s: "https://vault/foo6s"

  tasks:


  - name: "Get container name, for example: grafana, key: foo1, value: https://etcd/foo1"
    debug:
      msg: "Container name: {{ item.0.key }} Key: {{ item.1.key }} Value: {{ item.1.value }}"
    vars: 
      foo: "{{ (containers.values() | list) | map(attribute='variables') | map(attribute='docker') | map('dict2items')| list | flatten  }}"
      bar: "{{ containers | dict2items }}"
    loop: "{{ bar | product(foo) | list }}"