ElasticSearch: Updating nested document in array

Question

Given the document

curl -XPUT 'localhost:9200/test/me/here' -d '{
  "top" : [
    { "searchkey" : "change"},
    { "searchkey" : "keep"}
  ]
}'

I need an update query that will add new field to sub-document with searchkey equal to change and will keep any other sub-document intact. The expected result is then:

{
  "top" : [
    { "searchkey" : "change", "newfield" : "newvalue"},
    { "searchkey" : "keep"}
  ]
}

Running query that selects inner document by index works, but I do not know the inner order in advance and it is quite fragile anyways:

curl -XPOST 'localhost:9200/test/me/here/_update' -d '{
    "script" : "ctx._source.top[0].newfield = v",
    "params" : {
      "v" : "newvalue"
    }
}'

Is there a way to tell ES to add the new field to the inner document that matches some condition? Something like:

curl -XPOST 'localhost:9200/test/me/here/_update' -d '{
    "script" : "ctx._source.top[ctx._source.top.searchkey == s].newfield = v",
    "params" : {
      "s" : "change",
      "v" : "newvalue"
    }
}'

Or, will I do better and save some headache if I eliminate the array and transform the document to:

{
"change" : {},
"keep" : {}
}

Answer 1

You can use the update with script. See example:

PUT test/data/3/
{
   "source": [
     {
       "name": "A",
       "count": 1
     },
     {
       "name": "B",
       "count": 2
     },
     {
       "name": "c",
       "count": 3
     }
   ]
}

GET test/data/3

POST test/data/3/_update
{
 "script": " for (int i = 0; i < source.size(); i++) {boolean f = false;for (int j = 0; j < ctx._source.source.size(); j++) {if (ctx._source.source[j].name == source[i].name) {ctx._source.source[j].count = source[i].count;f=true;break;}}\nif(!f){ctx._source.source.add(source[i]);}}",
 "params": {
   "source": [
     {
       "name": "A",
       "count": 10
     },
     {
       "name": "B",
       "count": 30
     },
     {
       "name": "D",
       "count": 50
     }
   ]
 }
}

GET test/data/3