Pass script level params into scripted metric aggs (elastic#28819)

Now params that are passed at the script level and at the aggregation level
are merged and can both be used in the aggregation scripts. If there are
any conflicts, aggregation level params will win. This may be followed
by another change detecting that case and throwing an exception to
disallow such conflicts.

Author: rationull

server/src/main/java/org/elasticsearch/search/aggregations/metrics/scripted/ScriptedMetricAggregationBuilder.java

@@ -37,6 +37,7 @@
 import org.elasticsearch.search.internal.SearchContext;
 
 import java.io.IOException;
+import java.util.Collections;
 import java.util.Map;
 import java.util.Objects;
 
@@ -198,20 +199,34 @@ protected ScriptedMetricAggregatorFactory doBuild(SearchContext context, Aggrega
             Builder subfactoriesBuilder) throws IOException {
 
         QueryShardContext queryShardContext = context.getQueryShardContext();
+
+        // Extract params from scripts and pass them along to ScriptedMetricAggregatorFactory, since it won't have
+        // access to them for the scripts it's given precompiled.
+
         ExecutableScript.Factory executableInitScript;
+        Map<String, Object> initScriptParams;
         if (initScript != null) {
             executableInitScript = queryShardContext.getScriptService().compile(initScript, ExecutableScript.AGGS_CONTEXT);
+            initScriptParams = initScript.getParams();
         } else {
             executableInitScript = p -> null;
+            initScriptParams = Collections.emptyMap();
         }
+
         SearchScript.Factory searchMapScript = queryShardContext.getScriptService().compile(mapScript, SearchScript.AGGS_CONTEXT);
+        Map<String, Object> mapScriptParams = mapScript.getParams();
+
         ExecutableScript.Factory executableCombineScript;
+        Map<String, Object> combineScriptParams;
         if (combineScript != null) {
-            executableCombineScript =queryShardContext.getScriptService().compile(combineScript, ExecutableScript.AGGS_CONTEXT);
+            executableCombineScript = queryShardContext.getScriptService().compile(combineScript, ExecutableScript.AGGS_CONTEXT);
+            combineScriptParams = combineScript.getParams();
         } else {
             executableCombineScript = p -> null;
+            combineScriptParams = Collections.emptyMap();
         }
-        return new ScriptedMetricAggregatorFactory(name, searchMapScript, executableInitScript, executableCombineScript, reduceScript,
+        return new ScriptedMetricAggregatorFactory(name, searchMapScript, mapScriptParams, executableInitScript, initScriptParams,
+                executableCombineScript, combineScriptParams, reduceScript,
                 params, queryShardContext.lookup(), context, parent, subfactoriesBuilder, metaData);
     }
 

server/src/main/java/org/elasticsearch/search/aggregations/metrics/scripted/ScriptedMetricAggregatorFactory.java

@@ -35,28 +35,35 @@
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
-import java.util.function.Function;
 
 public class ScriptedMetricAggregatorFactory extends AggregatorFactory<ScriptedMetricAggregatorFactory> {
 
     private final SearchScript.Factory mapScript;
+    private final Map<String, Object> mapScriptParams;
     private final ExecutableScript.Factory combineScript;
+    private final Map<String, Object> combineScriptParams;
     private final Script reduceScript;
-    private final Map<String, Object> params;
+    private final Map<String, Object> aggParams;
     private final SearchLookup lookup;
     private final ExecutableScript.Factory initScript;
+    private final Map<String, Object> initScriptParams;
 
-    public ScriptedMetricAggregatorFactory(String name, SearchScript.Factory mapScript, ExecutableScript.Factory initScript,
-                                           ExecutableScript.Factory combineScript, Script reduceScript, Map<String, Object> params,
+    public ScriptedMetricAggregatorFactory(String name, SearchScript.Factory mapScript, Map<String, Object> mapScriptParams,
+                                           ExecutableScript.Factory initScript, Map<String, Object> initScriptParams,
+                                           ExecutableScript.Factory combineScript, Map<String, Object> combineScriptParams,
+                                           Script reduceScript, Map<String, Object> aggParams,
                                            SearchLookup lookup, SearchContext context, AggregatorFactory<?> parent,
                                            AggregatorFactories.Builder subFactories, Map<String, Object> metaData) throws IOException {
         super(name, context, parent, subFactories, metaData);
         this.mapScript = mapScript;
+        this.mapScriptParams = mapScriptParams;
         this.initScript = initScript;
+        this.initScriptParams = initScriptParams;
         this.combineScript = combineScript;
+        this.combineScriptParams = combineScriptParams;
         this.reduceScript = reduceScript;
         this.lookup = lookup;
-        this.params = params;
+        this.aggParams = aggParams;
     }
 
     @Override
@@ -65,26 +72,26 @@ public Aggregator createInternal(Aggregator parent, boolean collectsFromSingleBu
         if (collectsFromSingleBucket == false) {
             return asMultiBucketAggregator(this, context, parent);
         }
-        Map<String, Object> params = this.params;
-        if (params != null) {
-            params = deepCopyParams(params, context);
+        Map<String, Object> aggParams = this.aggParams;
+        if (aggParams != null) {
+            aggParams = deepCopyParams(aggParams, context);
         } else {
-            params = new HashMap<>();
+            aggParams = new HashMap<>();
         }
-        if (params.containsKey("_agg") == false) {
-            params.put("_agg", new HashMap<String, Object>());
+        if (aggParams.containsKey("_agg") == false) {
+            aggParams.put("_agg", new HashMap<String, Object>());
         }
 
-        final ExecutableScript initScript = this.initScript.newInstance(params);
-        final SearchScript.LeafFactory mapScript = this.mapScript.newFactory(params, lookup);
-        final ExecutableScript combineScript = this.combineScript.newInstance(params);
+        final ExecutableScript initScript = this.initScript.newInstance(mergeParams(aggParams, initScriptParams));
+        final SearchScript.LeafFactory mapScript = this.mapScript.newFactory(mergeParams(aggParams, mapScriptParams), lookup);
+        final ExecutableScript combineScript = this.combineScript.newInstance(mergeParams(aggParams, combineScriptParams));
 
         final Script reduceScript = deepCopyScript(this.reduceScript, context);
         if (initScript != null) {
             initScript.run();
         }
         return new ScriptedMetricAggregator(name, mapScript,
-                combineScript, reduceScript, params, context, parent,
+                combineScript, reduceScript, aggParams, context, parent,
                 pipelineAggregators, metaData);
     }
 
@@ -128,5 +135,16 @@ private static <T> T deepCopyParams(T original, SearchContext context) {
         return clone;
     }
 
+    private static Map<String, Object> mergeParams(Map<String, Object> agg, Map<String, Object> script) {
+        // TODO Should we throw an exception when param names conflict between aggregation and script? Need to add test coverage
+        // for error or override behavior depending on the decision. Should this check be added at call time or at
+        // construction?
 
+        // Aggregation level commands need to win in case of conflict so that params can keep the same identity and
+        // content across all the scripts that are run in the aggregation.
+        Map<String, Object> combined = new HashMap<>();
+        combined.putAll(script);
+        combined.putAll(agg);
+        return combined;
+    }
 }

server/src/test/java/org/elasticsearch/search/aggregations/metrics/ScriptedMetricIT.java

@@ -361,17 +361,17 @@ public void testMapWithParams() {
     }
 
     public void testMapWithParamsAndImplicitAggMap() {
-        Map<String, Object> params = new HashMap<>();
-        // don't put any _agg map in params
-        params.put("param1", "12");
-        params.put("param2", 1);
+        // Split the params up between the script and the aggregation.
+        // Don't put any _agg map in params.
+        Map<String, Object> scriptParams = Collections.singletonMap("param1", "12");
+        Map<String, Object> aggregationParams = Collections.singletonMap("param2", 1);
 
         // The _agg hashmap will be available even if not declared in the params map
-        Script mapScript = new Script(ScriptType.INLINE, CustomScriptPlugin.NAME, "_agg[param1] = param2", params);
+        Script mapScript = new Script(ScriptType.INLINE, CustomScriptPlugin.NAME, "_agg[param1] = param2", scriptParams);
 
         SearchResponse response = client().prepareSearch("idx")
             .setQuery(matchAllQuery())
-            .addAggregation(scriptedMetric("scripted").params(params).mapScript(mapScript))
+            .addAggregation(scriptedMetric("scripted").params(aggregationParams).mapScript(mapScript))
             .get();
         assertSearchResponse(response);
         assertThat(response.getHits().getTotalHits(), equalTo(numDocs));

server/src/test/java/org/elasticsearch/search/aggregations/metrics/scripted/ScriptedMetricAggregatorTests.java

@@ -64,8 +64,15 @@ public class ScriptedMetricAggregatorTests extends AggregatorTestCase {
             Collections.emptyMap());
     private static final Script COMBINE_SCRIPT_SCORE = new Script(ScriptType.INLINE, MockScriptEngine.NAME, "combineScriptScore",
             Collections.emptyMap());
-    private static final Map<String, Function<Map<String, Object>, Object>> SCRIPTS = new HashMap<>();
 
+    private static final Script INIT_SCRIPT_PARAMS = new Script(ScriptType.INLINE, MockScriptEngine.NAME, "initScriptParams",
+            Collections.singletonMap("initialValue", 24));
+    private static final Script MAP_SCRIPT_PARAMS = new Script(ScriptType.INLINE, MockScriptEngine.NAME, "mapScriptParams",
+            Collections.singletonMap("itemValue", 12));
+    private static final Script COMBINE_SCRIPT_PARAMS = new Script(ScriptType.INLINE, MockScriptEngine.NAME, "combineScriptParams",
+            Collections.singletonMap("divisor", 4));
+
+    private static final Map<String, Function<Map<String, Object>, Object>> SCRIPTS = new HashMap<>();
 
     @BeforeClass
     @SuppressWarnings("unchecked")
@@ -99,6 +106,26 @@ public static void initMockScripts() {
             Map<String, Object> agg = (Map<String, Object>) params.get("_agg");
             return ((List<Double>) agg.get("collector")).stream().mapToDouble(Double::doubleValue).sum();
         });
+
+        SCRIPTS.put("initScriptParams", params -> {
+            Map<String, Object> agg = (Map<String, Object>) params.get("_agg");
+            Integer initialValue = (Integer)params.get("initialValue");
+            ArrayList<Integer> collector = new ArrayList();
+            collector.add(initialValue);
+            agg.put("collector", collector);
+            return agg;
+        });
+        SCRIPTS.put("mapScriptParams", params -> {
+            Map<String, Object> agg = (Map<String, Object>) params.get("_agg");
+            Integer itemValue = (Integer) params.get("itemValue");
+            ((List<Integer>) agg.get("collector")).add(itemValue);
+            return agg;
+        });
+        SCRIPTS.put("combineScriptParams", params -> {
+            Map<String, Object> agg = (Map<String, Object>) params.get("_agg");
+            int divisor = ((Integer) params.get("divisor"));
+            return ((List<Integer>) agg.get("collector")).stream().mapToInt(Integer::intValue).map(i -> i / divisor).sum();
+        });
     }
 
     @SuppressWarnings("unchecked")
@@ -187,6 +214,25 @@ public void testScriptedMetricWithCombineAccessesScores() throws IOException {
         }
     }
 
+    public void testScriptParamsPassedThrough() throws IOException {
+        try (Directory directory = newDirectory()) {
+            try (RandomIndexWriter indexWriter = new RandomIndexWriter(random(), directory)) {
+                for (int i = 0; i < 100; i++) {
+                    indexWriter.addDocument(singleton(new SortedNumericDocValuesField("number", i)));
+                }
+            }
+
+            try (IndexReader indexReader = DirectoryReader.open(directory)) {
+                ScriptedMetricAggregationBuilder aggregationBuilder = new ScriptedMetricAggregationBuilder(AGG_NAME);
+                aggregationBuilder.initScript(INIT_SCRIPT_PARAMS).mapScript(MAP_SCRIPT_PARAMS).combineScript(COMBINE_SCRIPT_PARAMS);
+                ScriptedMetric scriptedMetric = search(newSearcher(indexReader, true, true), new MatchAllDocsQuery(), aggregationBuilder);
+
+                // The result value depends on the script params.
+                assertEquals(306, scriptedMetric.aggregation());
+            }
+        }
+    }
+
     /**
      * We cannot use Mockito for mocking QueryShardContext in this case because
      * script-related methods (e.g. QueryShardContext#getLazyExecutableScript)