Mark aggregated condition ready only when No error happened

[nan-yu]

Fixes #183

[nan-yu]

/assign @barney-s

[ant31]

is it possible that all components are ready but there's an error ?
I assume yes, the message / status should reflect that or it's still confusing.

The status would be in error with "some components not ready", as a user I would check which components isn't ready but won't find any....
Could we add a separate case:
something like :

if errs != nil { 
  "there's an error"
} else if aggReady {
 "all components ready"
} else 
{
 "some components not ready" // 'some' could be replaced with (len(objectStatuses)-countReady)
}

[nan-yu]

There are two types of conditions: Ready and Error and we need to set both.
I think we can leverage the Unknown status for the Ready condition:

if errs != nil {
   //set ready condition to unknown
} else if aggReady {
  "all components ready"
} else {
    "x components not ready"
}

if errs != nil {
   setErrorCondition
} else {
   clearErrorCondition
}

[nan-yu]

Example when errors happened in aggregating statuses:

"status": {
    "observedGeneration": 1,
    "conditions": [
      {
        "type": "Ready",
        "status": "Unknown",
        "reason": "ComponentsReadyUnknown",
        "message": "failed to aggregate all components' statuses, check the Error condition for details",
        "lastUpdateTime": "2020-03-06T20:20:29Z",
        "lastTransitionTime": "2020-03-06T20:20:29Z"
      },
      {
        "type": "Error",
        "status": "True",
        "reason": "ErrorSeen",
        "message": "[fetchComponentListResources error, setOwnerRefForResources error, service status error, statefulset status error]",
        "lastUpdateTime": "2020-03-06T20:20:29Z",
        "lastTransitionTime": "2020-03-06T20:20:29Z"
      }
    ],
    "components": [
      {
        "link": "/api/v1/namespaces/default/services/wordpress-mysql-hsvc",
        "name": "wordpress-mysql-hsvc",
        "kind": "Service",
        "status": "Unknown"
      },
      {
        "link": "/api/v1/namespaces/default/services/wordpress-webserver-hsvc",
        "name": "wordpress-webserver-hsvc",
        "kind": "Service",
        "status": "Unknown"
      },
      {
        "link": "/api/v1/namespaces/default/services/wordpress-webserver-svc",
        "name": "wordpress-webserver-svc",
        "kind": "Service",
        "status": "Unknown"
      },
      {
        "link": "/apis/apps/v1/namespaces/default/statefulsets/wordpress-mysql",
        "name": "wordpress-mysql",
        "kind": "StatefulSet",
        "group": "apps",
        "status": "Unknown"
      },
      {
        "link": "/apis/apps/v1/namespaces/default/statefulsets/wordpress-webserver",
        "name": "wordpress-webserver",
        "kind": "StatefulSet",
        "group": "apps",
        "status": "Unknown"
      }
    ],
    "componentsReady": "0/5"
  }

[ant31]

thank you,
/lgtm
/approve

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