Put mongo update in Nifi

[#1]

How can I update an existing document (replacing it with the new one received) based on a specific key?

the document is something similar to this one:

{

"field1": {

"key1": "value",

"key2": "value",

"key3": "value"

},

"key": {

"subfield": {

"uuid": 1234

}

}

}

the key is key.subfield.uuid and it is contained into the json entering in the putmongo processor