extending an list field in elasticsearch document - python-3.x

Question

I have user_data field in my elasticsearch index document for eg;
sample doc:
user_data : [
{
userid :1,
order_id :32
},
{
userid :8,
order_id : 99
}
]
I have another set of user data in my memory which i want to extend (adding list to list)
data in memory:
preserved_user_data : [
{
userid :991,
order_id :89
},
{
userid :89,
order_id :76
}
]
I want to update that document to :
user_data : [
{
userid :1,
order_id :32
},
{
userid :8,
order_id : 99
},
{
userid :991,
order_id :89
},
{
userid :89,
order_id :76
}
]
i have tried using script ctx._source.user_data += params.preserved_user_data but it makes the document's field empty array.
P.S : I am doing this via parallel bulk using op type : update on ES 7.1.1

Answer 1

A sample query using update script to append array to array in document
Query:
POST index35/_update/tg8DwHAB4HO3_VSZUdzR
{
"script": {
"lang": "painless",
"inline": "if(!ctx._source.containsKey('user_data')){ctx._source['user_data']=[]} for(int i=0;i<params.data.length;i++){ctx._source.user_data.add(params.data[i])}",
"params": {
"data": [
{
"userid": 991,
"order_id": 89
},
{
"userid": 89,
"order_id": 76
}
]
}
}
}
Result:
"hits" : [
{
"_index" : "index35",
"_type" : "_doc",
"_id" : "tg8DwHAB4HO3_VSZUdzR",
"_score" : 1.0,
"_source" : {
"user_data" : [
{
"userid" : 1,
"order_id" : 32
},
{
"userid" : 8,
"order_id" : 99
},
{
"userid" : 991,
"order_id" : 89
},
{
"userid" : 89,
"order_id" : 76
}
]
}
}
]
}