Scripted metric aggregations
The scripted_metric metric is a multi-value metric aggregation that returns metrics calculated from a specified script.
A script has four stages: the initial stage, the map stage, the combine stage, and the reduce stage.
init_script: (OPTIONAL) Sets the initial state and executes before any collection of documents.map_script: Checks the value of thetypefield and executes the aggregation on the collected documents.combine_script: Aggregates the state returned from every shard. The aggregated value is returned to the coordinating node.reduce_script: Provides access to the variable states; this variable combines the results from thecombine_scripton each shard into an array.
The following example aggregates the different HTTP response types in web log data:
GET opensearch_dashboards_sample_data_logs/_search
{
"size": 0,
"aggregations": {
"responses.counts": {
"scripted_metric": {
"init_script": "state.responses = ['error':0L,'success':0L,'other':0L]",
"map_script": """
def code = doc['response.keyword'].value;
if (code.startsWith('5') || code.startsWith('4')) {
state.responses.error += 1 ;
} else if(code.startsWith('2')) {
state.responses.success += 1;
} else {
state.responses.other += 1;
}
""",
"combine_script": "state.responses",
"reduce_script": """
def counts = ['error': 0L, 'success': 0L, 'other': 0L];
for (responses in states) {
counts.error += responses['error'];
counts.success += responses['success'];
counts.other += responses['other'];
}
return counts;
"""
}
}
}
}
Example response
...
"aggregations" : {
"responses.counts" : {
"value" : {
"other" : 0,
"success" : 12832,
"error" : 1242
}
}
}
}