@Override public InternalAggregation reduce(InternalAggregation aggregation, ReduceContext reduceContext) { InternalMultiBucketAggregation< InternalMultiBucketAggregation, InternalMultiBucketAggregation.InternalBucket> originalAgg = (InternalMultiBucketAggregation< InternalMultiBucketAggregation, InternalMultiBucketAggregation.InternalBucket>) aggregation; List<? extends Bucket> buckets = originalAgg.getBuckets(); CompiledScript compiledScript = reduceContext.scriptService().compile(script, ScriptContext.Standard.AGGS, reduceContext); List newBuckets = new ArrayList<>(); for (Bucket bucket : buckets) { Map<String, Object> vars = new HashMap<>(); if (script.getParams() != null) { vars.putAll(script.getParams()); } boolean skipBucket = false; for (Map.Entry<String, String> entry : bucketsPathsMap.entrySet()) { String varName = entry.getKey(); String bucketsPath = entry.getValue(); Double value = resolveBucketValue(originalAgg, bucket, bucketsPath, gapPolicy); if (GapPolicy.SKIP == gapPolicy && (value == null || Double.isNaN(value))) { skipBucket = true; break; } vars.put(varName, value); } if (skipBucket) { newBuckets.add(bucket); } else { ExecutableScript executableScript = reduceContext.scriptService().executable(compiledScript, vars); Object returned = executableScript.run(); if (returned == null) { newBuckets.add(bucket); } else { if (!(returned instanceof Number)) { throw new AggregationExecutionException( "series_arithmetic script for reducer [" + name() + "] must return a Number"); } List<InternalAggregation> aggs = new ArrayList<>(eagerTransform(bucket.getAggregations().asList(), FUNCTION)); aggs.add( new InternalSimpleValue( name(), ((Number) returned).doubleValue(), formatter, new ArrayList<PipelineAggregator>(), metaData())); InternalMultiBucketAggregation.InternalBucket newBucket = originalAgg.createBucket( new InternalAggregations(aggs), (InternalMultiBucketAggregation.InternalBucket) bucket); newBuckets.add(newBucket); } } } return originalAgg.create(newBuckets); }