groovy - Creating/updating array of objects in elasticsearch logstash output -

i facing issue using elastic search output logstash. here sample event

{     "guid":"someguid",     "nestedobject":{         "field1":"val1",         "field2":"val2"     } } 

i expect document id present in elasticsearch when update happens. here want have in elastic search document after 2 upserts:

{     "oldfield":"some old field original document before upserts."     "nestedobjects":[{         "field1":"val1",         "field2":"val2"         },         {         "field3":"val3",         "field4":"val4"         }] } 

here current elastic search output setting:

elasticsearch {     index => "elastictest"     action => "update"     document_type => "summary"     document_id => "%{guid}"     doc_as_upsert => true     script_lang => "groovy"     script_type => "inline"     retry_on_conflict => 3     script => "     if (ctx._source.nestedobjects) {     ctx._source.nestedobjects += event.nestedobject     } else {     ctx._source.nestedobjects = [event.nestedobject]     }     "     } 

here error getting:

response=>{"update"=>{"_index"=>"elastictest", "_type"=>"summary", "_id"=>"64648dd3-c1e9-45fd-a00b-5a4332c91ee9", "status"=>400,  "error"=>{"type"=>"mapper_parsing_exception", "reason"=>"failed parse [event.nestedobject]",  "caused_by"=>{"type"=>"illegal_argument_exception", "reason"=>"unknown property [field1]"}}}} 

the issue turned out internally generated mapping in elasticsearch due other documents same document_type conflicting type on field nestedobject. caused elastic throw mapper parsing exception. fixing this, fixed issue.