cygnus mongo sink and meta data storing

I tried to stored this meta data entity but seems like cygnus is only storing entity data no meta data was stored in the data base.

Here is how I update my entity using NGSI v1 updateContext

{
    "contextElements": [
        {
            "type": "dummyMeta",
            "isPattern": "false",
            "id": "dummyMeta",
            "attributes": [
                {
                    "name": "dummy",
                    "type": "float",
                    "value": "26.5",
                    "metadatas": [
                        {
                            "name": "accuracy",
                            "type": "float",
                            "value": "1"
                        }
                    ]
                }
            ]
        }
    ],
    "updateAction": "APPEND"
}

Here is the payload subscription:

{

    "entities": [
      {
        "id": "dummyMeta",
        "type": "dummyMeta",
        "isPattern": "false"
      }
    ],

      "attributes": [
        "dummy"
      ]

  ,
  "reference": "http://cygnusserver.ddns.net:5050/notify",
  "duration":"P1M",
   "notifyConditions": [
        {
            "type": "ONCHANGE",
            "condValues": [
                "dummy"
            ]
        }
    ],
    "throttling": "PT5S"
}

here is how it is stored in the data base

> db['kura_/egmmqtt_dummyMeta_dummyMeta'].find().sort({$natural:-1})
{ "_id" : ObjectId("57c929d8902531258a3c6ed0"), "recvTime" : ISODate("2016-09-02T07:27:18.331Z"), "attrName" : "dummy", "attrType" : "float", "attrValue" : "26.5" }
{ "_id" : ObjectId("57c92990902531258a3c6ecc"), "recvTime" : ISODate("2016-09-02T07:26:04.148Z"), "attrName" : "dummy", "attrType" : "float", "attrValue" : "26.5" }

What am I missing to be able to store the whole information (data and metadata) about the attribute? Thanks in advance for your help!

MongoDB sink does not save the metadata by design. It is a requirement by our internal products currently using Cygnus.

Being said that, I think it should not be very difficult to modify the code by your side in order to save the metadata.

Alternatively, I can create an issue about optionally save metadata when configured through a configuration parameter. Nevertheless, I cannot commit with an implementation date.