Add ScriptCompiler interface (#70657)

TypeParser.ParserContext exposes a ScriptService allowing type parsers to
compile scripts from runtime fields (and in future, index-time scripts). However,
ScriptService itself is a fairly heavyweight object, and you can only add script
parsers to it via the Plugin mechanism.

To make testing easier, this commit extracts a ScriptCompiler interface and makes
that available from ParserContext instead.

Author: romseygeek

server/src/main/java/org/elasticsearch/index/mapper/Mapper.java

@@ -16,7 +16,7 @@
 import org.elasticsearch.index.analysis.IndexAnalyzers;
 import org.elasticsearch.index.query.SearchExecutionContext;
 import org.elasticsearch.index.similarity.SimilarityProvider;
-import org.elasticsearch.script.ScriptService;
+import org.elasticsearch.script.ScriptCompiler;
 
 import java.util.Map;
 import java.util.Objects;
@@ -52,7 +52,7 @@ class ParserContext {
             private final Version indexVersionCreated;
             private final Supplier<SearchExecutionContext> searchExecutionContextSupplier;
             private final DateFormatter dateFormatter;
-            private final ScriptService scriptService;
+            private final ScriptCompiler scriptCompiler;
             private final IndexAnalyzers indexAnalyzers;
             private final IndexSettings indexSettings;
             private final BooleanSupplier idFieldDataEnabled;
@@ -63,7 +63,7 @@ public ParserContext(Function<String, SimilarityProvider> similarityLookupServic
                                  Version indexVersionCreated,
                                  Supplier<SearchExecutionContext> searchExecutionContextSupplier,
                                  DateFormatter dateFormatter,
-                                 ScriptService scriptService,
+                                 ScriptCompiler scriptCompiler,
                                  IndexAnalyzers indexAnalyzers,
                                  IndexSettings indexSettings,
                                  BooleanSupplier idFieldDataEnabled) {
@@ -73,7 +73,7 @@ public ParserContext(Function<String, SimilarityProvider> similarityLookupServic
                 this.indexVersionCreated = indexVersionCreated;
                 this.searchExecutionContextSupplier = searchExecutionContextSupplier;
                 this.dateFormatter = dateFormatter;
-                this.scriptService = scriptService;
+                this.scriptCompiler = scriptCompiler;
                 this.indexAnalyzers = indexAnalyzers;
                 this.indexSettings = indexSettings;
                 this.idFieldDataEnabled = idFieldDataEnabled;
@@ -134,10 +134,10 @@ public DateFormatter getDateFormatter() {
             protected Function<String, SimilarityProvider> similarityLookupService() { return similarityLookupService; }
 
             /**
-             * The {@linkplain ScriptService} to compile scripts needed by the {@linkplain Mapper}.
+             * The {@linkplain ScriptCompiler} to compile scripts needed by the {@linkplain Mapper}.
              */
-            public ScriptService scriptService() {
-                return scriptService;
+            public ScriptCompiler scriptCompiler() {
+                return scriptCompiler;
             }
 
             ParserContext createMultiFieldContext(ParserContext in) {
@@ -151,7 +151,7 @@ ParserContext createDynamicTemplateFieldContext(ParserContext in) {
             private static class MultiFieldParserContext extends ParserContext {
                 MultiFieldParserContext(ParserContext in) {
                     super(in.similarityLookupService, in.typeParsers, in.runtimeTypeParsers, in.indexVersionCreated,
-                        in.searchExecutionContextSupplier, in.dateFormatter, in.scriptService, in.indexAnalyzers, in.indexSettings,
+                        in.searchExecutionContextSupplier, in.dateFormatter, in.scriptCompiler, in.indexAnalyzers, in.indexSettings,
                         in.idFieldDataEnabled);
                 }
 
@@ -162,7 +162,7 @@ private static class MultiFieldParserContext extends ParserContext {
             private static class DynamicTemplateParserContext extends ParserContext {
                 DynamicTemplateParserContext(ParserContext in) {
                     super(in.similarityLookupService, in.typeParsers, in.runtimeTypeParsers, in.indexVersionCreated,
-                        in.searchExecutionContextSupplier, in.dateFormatter, in.scriptService, in.indexAnalyzers, in.indexSettings,
+                        in.searchExecutionContextSupplier, in.dateFormatter, in.scriptCompiler, in.indexAnalyzers, in.indexSettings,
                         in.idFieldDataEnabled);
                 }
 

server/src/main/java/org/elasticsearch/index/mapper/MapperService.java

@@ -41,7 +41,7 @@
 import org.elasticsearch.index.query.SearchExecutionContext;
 import org.elasticsearch.index.similarity.SimilarityService;
 import org.elasticsearch.indices.InvalidTypeNameException;
-import org.elasticsearch.script.ScriptService;
+import org.elasticsearch.script.ScriptCompiler;
 
 import java.io.Closeable;
 import java.io.IOException;
@@ -126,15 +126,15 @@ public enum MergeReason {
     public MapperService(IndexSettings indexSettings, IndexAnalyzers indexAnalyzers, NamedXContentRegistry xContentRegistry,
                          SimilarityService similarityService, MapperRegistry mapperRegistry,
                          Supplier<SearchExecutionContext> searchExecutionContextSupplier, BooleanSupplier idFieldDataEnabled,
-                         ScriptService scriptService) {
+                         ScriptCompiler scriptCompiler) {
         super(indexSettings);
         this.indexVersionCreated = indexSettings.getIndexVersionCreated();
         this.indexAnalyzers = indexAnalyzers;
         this.mapperRegistry = mapperRegistry;
         Function<DateFormatter, Mapper.TypeParser.ParserContext> parserContextFunction =
             dateFormatter -> new Mapper.TypeParser.ParserContext(similarityService::getSimilarity, mapperRegistry.getMapperParsers()::get,
                 mapperRegistry.getRuntimeFieldTypeParsers()::get, indexVersionCreated, searchExecutionContextSupplier, dateFormatter,
-                scriptService, indexAnalyzers, indexSettings, idFieldDataEnabled);
+                scriptCompiler, indexAnalyzers, indexSettings, idFieldDataEnabled);
         this.documentParser = new DocumentParser(xContentRegistry, parserContextFunction);
         Map<String, MetadataFieldMapper.TypeParser> metadataMapperParsers =
             mapperRegistry.getMetadataMapperParsers(indexSettings.getIndexVersionCreated());

server/src/main/java/org/elasticsearch/runtimefields/mapper/BooleanScriptFieldType.java

@@ -42,7 +42,7 @@ protected AbstractScriptFieldType<?> buildFieldType() {
             if (script.get() == null) {
                 return new BooleanScriptFieldType(name, BooleanFieldScript.PARSE_FROM_SOURCE, this);
             }
-            BooleanFieldScript.Factory factory = parserContext.scriptService().compile(script.getValue(), BooleanFieldScript.CONTEXT);
+            BooleanFieldScript.Factory factory = parserContext.scriptCompiler().compile(script.getValue(), BooleanFieldScript.CONTEXT);
             return new BooleanScriptFieldType(name, factory, this);
         }
     });

server/src/main/java/org/elasticsearch/runtimefields/mapper/DateScriptFieldType.java

@@ -88,7 +88,7 @@ protected AbstractScriptFieldType<?> buildFieldType() {
             if (script.get() == null) {
                 return new DateScriptFieldType(name, DateFieldScript.PARSE_FROM_SOURCE, dateTimeFormatter, this);
             }
-            DateFieldScript.Factory factory = parserContext.scriptService().compile(script.getValue(), DateFieldScript.CONTEXT);
+            DateFieldScript.Factory factory = parserContext.scriptCompiler().compile(script.getValue(), DateFieldScript.CONTEXT);
             return new DateScriptFieldType(name, factory, dateTimeFormatter, this);
         }
     });

server/src/main/java/org/elasticsearch/runtimefields/mapper/DoubleScriptFieldType.java

@@ -42,7 +42,7 @@ protected AbstractScriptFieldType<?> buildFieldType() {
             if (script.get() == null) {
                 return new DoubleScriptFieldType(name, DoubleFieldScript.PARSE_FROM_SOURCE, this);
             }
-            DoubleFieldScript.Factory factory = parserContext.scriptService().compile(script.getValue(), DoubleFieldScript.CONTEXT);
+            DoubleFieldScript.Factory factory = parserContext.scriptCompiler().compile(script.getValue(), DoubleFieldScript.CONTEXT);
             return new DoubleScriptFieldType(name, factory, this);
         }
     });

server/src/main/java/org/elasticsearch/runtimefields/mapper/GeoPointScriptFieldType.java

@@ -46,7 +46,7 @@ protected AbstractScriptFieldType<?> buildFieldType() {
             if (script.get() == null) {
                 return new GeoPointScriptFieldType(name, GeoPointFieldScript.PARSE_FROM_SOURCE, this);
             }
-            GeoPointFieldScript.Factory factory = parserContext.scriptService().compile(script.getValue(), GeoPointFieldScript.CONTEXT);
+            GeoPointFieldScript.Factory factory = parserContext.scriptCompiler().compile(script.getValue(), GeoPointFieldScript.CONTEXT);
             return new GeoPointScriptFieldType(name, factory, this);
         }
     });

server/src/main/java/org/elasticsearch/runtimefields/mapper/IpScriptFieldType.java

@@ -51,7 +51,7 @@ protected AbstractScriptFieldType<?> buildFieldType() {
             if (script.get() == null) {
                 return new IpScriptFieldType(name, IpFieldScript.PARSE_FROM_SOURCE, this);
             }
-            IpFieldScript.Factory factory = parserContext.scriptService().compile(script.getValue(), IpFieldScript.CONTEXT);
+            IpFieldScript.Factory factory = parserContext.scriptCompiler().compile(script.getValue(), IpFieldScript.CONTEXT);
             return new IpScriptFieldType(name, factory, this);
         }
     });

server/src/main/java/org/elasticsearch/runtimefields/mapper/KeywordScriptFieldType.java

@@ -50,7 +50,7 @@ protected AbstractScriptFieldType<?> buildFieldType() {
             if (script.get() == null) {
                 return new KeywordScriptFieldType(name, StringFieldScript.PARSE_FROM_SOURCE, this);
             }
-            StringFieldScript.Factory factory = parserContext.scriptService().compile(script.getValue(), StringFieldScript.CONTEXT);
+            StringFieldScript.Factory factory = parserContext.scriptCompiler().compile(script.getValue(), StringFieldScript.CONTEXT);
             return new KeywordScriptFieldType(name, factory, this);
         }
     });

server/src/main/java/org/elasticsearch/runtimefields/mapper/LongScriptFieldType.java

@@ -42,7 +42,7 @@ protected AbstractScriptFieldType<?> buildFieldType() {
             if (script.get() == null) {
                 return new LongScriptFieldType(name, LongFieldScript.PARSE_FROM_SOURCE, this);
             }
-            LongFieldScript.Factory factory = parserContext.scriptService().compile(script.getValue(), LongFieldScript.CONTEXT);
+            LongFieldScript.Factory factory = parserContext.scriptCompiler().compile(script.getValue(), LongFieldScript.CONTEXT);
             return new LongScriptFieldType(name, factory, this);
         }
     });

server/src/main/java/org/elasticsearch/script/ScriptCompiler.java

@@ -0,0 +1,25 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0 and the Server Side Public License, v 1; you may not use this file except
+ * in compliance with, at your election, the Elastic License 2.0 or the Server
+ * Side Public License, v 1.
+ */
+
+package org.elasticsearch.script;
+
+/**
+ * Takes a Script definition and returns a compiled script factory
+ */
+public interface ScriptCompiler {
+
+    /**
+     * Takes a Script definition and returns a compiled script factory
+     * @param script            the Script to compile
+     * @param scriptContext     the ScriptContext defining how to compile the script
+     * @param <T>               the class of the compiled Script factory
+     * @return                  a Script factory
+     */
+    <T> T compile(Script script, ScriptContext<T> scriptContext);
+
+}