Elasticsearch Groovy Script Syntax For Generation Of Nested Fields

The below simple ES Groovy script takes a python dictionary with order data (orderItem) and appends it to a list of orders within Elasticsearch. The list with all orderItems then r

Solution 1:

I think that initially your _source.Orders field is null, i.e. not even an empty array.

Moreover, containsKey might not be the right way to go, because your _source might contain a field named Orders whose type might not be an array, i.e. it might be a dynamic object standing for an existing order, or worse, just a plain string.

I suggest you try a different approach by first checking if Orders is null and initialize it to an empty array if not. Then you can append the orderItem to the resulting array:

{
  "script" : "ctx._source.Orders = ((ctx._source.Orders ?: []) += orderItem)",
  "params" : {
    "orderItem" : orderItem
  }      
}

An alternative to this would be to simply ensure that when you index your document the first time, you make sure that the Orders field is initialized with an empty array [] and then your script could simply append orderItems to that array.

UPDATE

Based on your comments, I'm revising my answer in order to deal with the case where Orders is a dynamic object containing shop names as keys and each of those keys points to an array of orders for that shop. It's basically the same idea as earlier, just that we need to deal with one more level (i.e. the shop names).

First the script makes sure that the Orders object exists and then it makes sure that the shop array within the Orders object exists as well. All that remains to do is to append the orderItem to the shop array:

{
  "script" : "ctx._source.Orders = ctx._source.Orders ?: [shopName:'']; ctx._source.Orders[shopName] = ((ctx._source.Orders[shopName] ?: []) + orderItem); ctx._source.TimestampUpdated = TimestampUpdated",
  "params" : {
    "shopName": shopName,
    "orderItem" : orderItem,
    "TimestampUpdated":datetime.now().isoformat()
  }      
}