Elasticsearch - Bucket_script and buckets_paths return "Could not find aggregator type" - elasticsearch

Question

I'm trying to calculate some percentages with Elasticsearch but I have a (small) problem. I want ES to calculate the following: "(wins / Total) * 100".
So I added:
"bucket_script": {
"buckets_paths": {
"total": "TotalStatus",
"wins": "TotalWins"
},
"script": " (total/ wins) * 100"
}
To my ES request, which looks like:
{
"size": 0,
"query": {
"bool": {
"must": [
{
"query_string": {
"query": "*",
"analyze_wildcard": true
}
}
],
"must_not": []
}
},
"aggs": {
"status": {
"terms": {
"field": "status.raw"
}
},
"wins": {
"terms": {
"field": "status.raw",
"include": {
"pattern": "Accepted|Released|Closed"
}
}
},
"losses": {
"terms": {
"field": "status.raw",
"include": {
"pattern": "Rejected"
}
}
},
"TotalStatus": {
"sum_bucket": {
"buckets_path": "status._count"
}
},
"TotalWins": {
"sum_bucket": {
"buckets_path": "wins._count"
}
},
"TotalLosses": {
"sum_bucket": {
"buckets_path": "losses._count"
}
}
}
}
This however returns the following error:
{
"error": {
"root_cause": [
{
"type": "parsing_exception",
"reason": "Could not find aggregator type [buckets_paths] in [bucket_script]",
"line": 54,
"col": 28
}
],
"type": "parsing_exception",
"reason": "Could not find aggregator type [buckets_paths] in [bucket_script]",
"line": 54,
"col": 28
},
"status": 400
}
Any idea's?

Answer 1

I played a lot with bucket_script but I guess it might not be possible as it can't be top level aggregation and also you would need both total_wins and total_status coming from same parent aggregation with one numeric value and I think it might not be possible.
But it can be solved by scripted metric aggregation
{
"size": 0,
"aggs": {
"win_loss_ratio": {
"scripted_metric": {
"init_script": "_agg['win_count'] = 0; _agg['total_count'] = 0; _agg['win_status']=['Accepted','Released','Closed'];",
"map_script": "if (doc['status.raw'].value in _agg['win_status']) { _agg['win_count']+=1};if (doc['status.raw'].value) { _agg['total_count']+=1}",
"combine_script": "return [_agg['win_count'],_agg['total_count']];",
"reduce_script": "total_win = 0; total_status_count=0; for (a in _aggs) { total_win += a[0]; total_status_count += a[1] }; if(total_win == 0) {return 0} else {return (total_status_count/total_win) * 100}"
}
}
}
}
init_script initializes three variables. win_status array has all the values corresponding to win status.
map_script iterates through every document, if the status.raw value is in win_status then win_count is incremented and if it has any value at all total_count is incremented(you could remove this if condition if you also want to include null values)
combine_script gets all values per shard
reduce_script sums all the values and then divides it. There is also a check so that we dont divide by zero or script will throw exception.