openstack.yaml proposal

openstack.yaml

roles_metadata:
  controller:
    conflicts:
      - compute
    conditions:
      - condition: "cluster:mode == 'multinode'"
          then:
            all:
              - condition: "selectedNodes._length <= 1"
                warning: "Multi-node environment cannot have more than one controller node."
              - not:
                  exists:
                    where: "cluster:nodes"
                    variable: node
                    condition:
                      all:
                        - not: "<node>.id in selectedNodes._pluck('id')"
                        - condition: "<node>._hasRole('controller')"
                        - not: "<node>._pending_deletion"
          else: true
      - condition: "cluster:mode == 'ha_compact'"
        then:
          recommended:
            expression: "cluster:nodes._length >= <value>"
            value: 3
            warning: "At least <value> controller nodes are recommended for HA deployment."

spec

EXPRESSIONS
---
<x> in <list>: _.contains(<list>, <x>)



eval(<expression>) should return object of type:
{
  value: bool,
  warning: <condition>.warning if evaluated to false
}



CONDITIONS
---
condition: <expression>

return: eval(<expression>)

---
condition: <expression>
  then: <condition>

return: if(eval(expression)) { return eval(<condition>) } else { eval(false) }

---
condition: <expression>
  then: <condition>
  else: <else_condition>

return: if(eval(expression)) { return eval(<condition>) } else { eval(<else_condition>) }



---
all:
  - <condition1>
  - <condition2>
  - ...

return: eval(<condition1>) && eval(<condition2>) && ...

---
not: <condition>

return: !eval(<condition>)

---
exists:
  where: <list>
  variable: <variable_name>
  condition: <condition>

return: _.filter(eval(<list>), function(variable) { return eval(<condition> with variable as <variable_name>); }).length > 0

---
recommended:
  expression: <expression>
  value: <value>
  warning: <warning>

return: eval(<expression> with value as <value>)

The return expression of 'recommended' is not taken into account when evaluating
compound expressions (we are only interested in the 'warning' field returned
when evaluated to false).



SPECIAL VARIABLES:
---
<list>._length: list.length

---
<list>._pluck(<what>): _.pluck(<list>, <what>)