SCRIPTING: Terms set query expression

modules/lang-expression/src/main/java/org/elasticsearch/script/expression/ExpressionScriptEngine.java

@@ -48,6 +48,7 @@
 import org.elasticsearch.script.ScriptEngine;
 import org.elasticsearch.script.ScriptException;
 import org.elasticsearch.script.SearchScript;
+import org.elasticsearch.script.TermsSetQueryScript;
 import org.elasticsearch.search.lookup.SearchLookup;
 
 import java.io.IOException;
@@ -132,6 +133,9 @@ public boolean execute() {
         } else if (context.instanceClazz.equals(ScoreScript.class)) {
             ScoreScript.Factory factory = (p, lookup) -> newScoreScript(expr, lookup, p);
             return context.factoryClazz.cast(factory);
+        } else if (context.instanceClazz.equals(TermsSetQueryScript.class)) {
+            TermsSetQueryScript.Factory factory = (p, lookup) -> newTermsSetQueryScript(expr, lookup, p);
+            return context.factoryClazz.cast(factory);
         }
         throw new IllegalArgumentException("expression engine does not know how to handle script context [" + context.name + "]");
     }
@@ -292,6 +296,118 @@ private SearchScript.LeafFactory newSearchScript(Expression expr, SearchLookup l
         return new ExpressionSearchScript(expr, bindings, specialValue, needsScores);
     }
 
+    private TermsSetQueryScript.LeafFactory newTermsSetQueryScript(Expression expr, SearchLookup lookup, @Nullable Map<String, Object> vars) {
+        MapperService mapper = lookup.doc().mapperService();
+        // NOTE: if we need to do anything complicated with bindings in the future, we can just extend Bindings,
+        // instead of complicating SimpleBindings (which should stay simple)
+        SimpleBindings bindings = new SimpleBindings();
+        for (String variable : expr.variables) {
+            try {
+                if (vars != null && vars.containsKey(variable)) {
+                    // NOTE: by checking for the variable in vars first, it allows masking document fields with a global constant,
+                    // but if we were to reverse it, we could provide a way to supply dynamic defaults for documents missing the field?
+                    Object value = vars.get(variable);
+                    if (value instanceof Number) {
+                        bindings.add(variable, new DoubleConstValueSource(((Number) value).doubleValue()).asDoubleValuesSource());
+                    } else {
+                        throw new ParseException("Parameter [" + variable + "] must be a numeric type", 0);
+                    }
+
+                } else {
+                    String fieldname = null;
+                    String methodname = null;
+                    String variablename = "value"; // .value is the default for doc['field'], its optional.
+                    boolean dateAccessor = false; // true if the variable is of type doc['field'].date.xxx
+                    VariableContext[] parts = VariableContext.parse(variable);
+                    if (parts[0].text.equals("doc") == false) {
+                        throw new ParseException("Unknown variable [" + parts[0].text + "]", 0);
+                    }
+                    if (parts.length < 2 || parts[1].type != VariableContext.Type.STR_INDEX) {
+                        throw new ParseException("Variable 'doc' must be used with a specific field like: doc['myfield']", 3);
+                    } else {
+                        fieldname = parts[1].text;
+                    }
+                    if (parts.length == 3) {
+                        if (parts[2].type == VariableContext.Type.METHOD) {
+                            methodname = parts[2].text;
+                        } else if (parts[2].type == VariableContext.Type.MEMBER) {
+                            variablename = parts[2].text;
+                        } else {
+                            throw new IllegalArgumentException("Only member variables or member methods may be accessed on a field when not accessing the field directly");
+                        }
+                    }
+                    if (parts.length > 3) {
+                        // access to the .date "object" within the field
+                        if (parts.length == 4 && ("date".equals(parts[2].text) || "getDate".equals(parts[2].text))) {
+                            if (parts[3].type == VariableContext.Type.METHOD) {
+                                methodname = parts[3].text;
+                                dateAccessor = true;
+                            } else if (parts[3].type == VariableContext.Type.MEMBER) {
+                                variablename = parts[3].text;
+                                dateAccessor = true;
+                            }
+                        }
+                        if (!dateAccessor) {
+                            throw new IllegalArgumentException("Variable [" + variable + "] does not follow an allowed format of either doc['field'] or doc['field'].method()");
+                        }
+                    }
+
+                    MappedFieldType fieldType = mapper.fullName(fieldname);
+
+                    if (fieldType == null) {
+                        throw new ParseException("Field [" + fieldname + "] does not exist in mappings", 5);
+                    }
+
+                    IndexFieldData<?> fieldData = lookup.doc().getForField(fieldType);
+
+                    // delegate valuesource creation based on field's type
+                    // there are three types of "fields" to expressions, and each one has a different "api" of variables and methods.
+
+                    final ValueSource valueSource;
+                    if (fieldType instanceof GeoPointFieldType) {
+                        // geo
+                        if (methodname == null) {
+                            valueSource = GeoField.getVariable(fieldData, fieldname, variablename);
+                        } else {
+                            valueSource = GeoField.getMethod(fieldData, fieldname, methodname);
+                        }
+                    } else if (fieldType instanceof DateFieldMapper.DateFieldType) {
+                        if (dateAccessor) {
+                            // date object
+                            if (methodname == null) {
+                                valueSource = DateObject.getVariable(fieldData, fieldname, variablename);
+                            } else {
+                                valueSource = DateObject.getMethod(fieldData, fieldname, methodname);
+                            }
+                        } else {
+                            // date field itself
+                            if (methodname == null) {
+                                valueSource = DateField.getVariable(fieldData, fieldname, variablename);
+                            } else {
+                                valueSource = DateField.getMethod(fieldData, fieldname, methodname);
+                            }
+                        }
+                    } else if (fieldData instanceof IndexNumericFieldData) {
+                        // number
+                        if (methodname == null) {
+                            valueSource = NumericField.getVariable(fieldData, fieldname, variablename);
+                        } else {
+                            valueSource = NumericField.getMethod(fieldData, fieldname, methodname);
+                        }
+                    } else {
+                        throw new ParseException("Field [" + fieldname + "] must be numeric, date, or geopoint", 5);
+                    }
+                    bindings.add(variable, valueSource.asDoubleValuesSource());
+                }
+            } catch (Exception e) {
+                // we defer "binding" of variables until here: give context for that variable
+                throw convertToScriptException("link error", expr.sourceText, variable, e);
+            }
+        }
+        ReplaceableConstDoubleValueSource specialValue = null;
+        return new ExpressionTermSetQueryScript(expr, bindings, specialValue);
+    }
+
     /**
      * This is a hack for filter scripts, which must return booleans instead of doubles as expression do.
      * See https://github.com/elastic/elasticsearch/issues/26429.

modules/lang-expression/src/main/java/org/elasticsearch/script/expression/ExpressionTermSetQueryScript.java

@@ -0,0 +1,76 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.elasticsearch.script.expression;
+
+import java.io.IOException;
+import org.apache.lucene.expressions.Bindings;
+import org.apache.lucene.expressions.Expression;
+import org.apache.lucene.expressions.SimpleBindings;
+import org.apache.lucene.index.LeafReaderContext;
+import org.apache.lucene.search.DoubleValues;
+import org.apache.lucene.search.DoubleValuesSource;
+import org.elasticsearch.script.GeneralScriptException;
+import org.elasticsearch.script.TermsSetQueryScript;
+
+/**
+ * A bridge to evaluate an {@link Expression} against {@link Bindings} in the context
+ * of a {@link TermsSetQueryScript}.
+ */
+class ExpressionTermSetQueryScript implements TermsSetQueryScript.LeafFactory {
+
+    final Expression exprScript;
+    final SimpleBindings bindings;
+    final DoubleValuesSource source;
+    final ReplaceableConstDoubleValueSource specialValue; // _value
+
+    ExpressionTermSetQueryScript(Expression e, SimpleBindings b, ReplaceableConstDoubleValueSource v) {
+        exprScript = e;
+        bindings = b;
+        source = exprScript.getDoubleValuesSource(bindings);
+        specialValue = v;
+    }
+
+    @Override
+    public TermsSetQueryScript newInstance(final LeafReaderContext leaf) throws IOException {
+        return new TermsSetQueryScript() {
+            // Fake the scorer until setScorer is called.
+            DoubleValues values = source.getValues(leaf, null);
+
+            @Override
+            public Number execute() {
+                try {
+                    return values.doubleValue();
+                } catch (Exception exception) {
+                    throw new GeneralScriptException("Error evaluating " + exprScript, exception);
+                }
+            }
+
+            @Override
+            public void setDocument(int d) {
+                try {
+                    values.advanceExact(d);
+                } catch (IOException e) {
+                    throw new IllegalStateException("Can't advance to doc using " + exprScript, e);
+                }
+            }
+        };
+    }
+
+}

modules/lang-expression/src/test/java/org/elasticsearch/script/expression/ExpressionTermsSetQueryTests.java

@@ -0,0 +1,105 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.elasticsearch.script.expression;
+
+import java.io.IOException;
+import java.text.ParseException;
+import java.util.Collections;
+import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.index.fielddata.AtomicNumericFieldData;
+import org.elasticsearch.index.fielddata.IndexNumericFieldData;
+import org.elasticsearch.index.fielddata.SortedNumericDoubleValues;
+import org.elasticsearch.index.mapper.MapperService;
+import org.elasticsearch.index.mapper.NumberFieldMapper.NumberFieldType;
+import org.elasticsearch.index.mapper.NumberFieldMapper.NumberType;
+import org.elasticsearch.script.ScriptException;
+import org.elasticsearch.script.TermsSetQueryScript;
+import org.elasticsearch.search.lookup.SearchLookup;
+import org.elasticsearch.test.ESTestCase;
+
+import static org.mockito.Matchers.anyInt;
+import static org.mockito.Matchers.anyObject;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+public class ExpressionTermsSetQueryTests extends ESTestCase {
+    private ExpressionScriptEngine service;
+    private SearchLookup lookup;
+
+    @Override
+    public void setUp() throws Exception {
+        super.setUp();
+
+        NumberFieldType fieldType = new NumberFieldType(NumberType.DOUBLE);
+        MapperService mapperService = mock(MapperService.class);
+        when(mapperService.fullName("field")).thenReturn(fieldType);
+        when(mapperService.fullName("alias")).thenReturn(fieldType);
+
+        SortedNumericDoubleValues doubleValues = mock(SortedNumericDoubleValues.class);
+        when(doubleValues.advanceExact(anyInt())).thenReturn(true);
+        when(doubleValues.nextValue()).thenReturn(2.718);
+
+        AtomicNumericFieldData atomicFieldData = mock(AtomicNumericFieldData.class);
+        when(atomicFieldData.getDoubleValues()).thenReturn(doubleValues);
+
+        IndexNumericFieldData fieldData = mock(IndexNumericFieldData.class);
+        when(fieldData.getFieldName()).thenReturn("field");
+        when(fieldData.load(anyObject())).thenReturn(atomicFieldData);
+
+        service = new ExpressionScriptEngine(Settings.EMPTY);
+        lookup = new SearchLookup(mapperService, ignored -> fieldData, null);
+    }
+
+    private TermsSetQueryScript.LeafFactory compile(String expression) {
+        TermsSetQueryScript.Factory factory =
+            service.compile(null, expression, TermsSetQueryScript.CONTEXT, Collections.emptyMap());
+        return factory.newFactory(Collections.emptyMap(), lookup);
+    }
+
+    public void testCompileError() {
+        ScriptException e = expectThrows(ScriptException.class, () -> {
+            compile("doc['field'].value * *@#)(@$*@#$ + 4");
+        });
+        assertTrue(e.getCause() instanceof ParseException);
+    }
+
+    public void testLinkError() {
+        ScriptException e = expectThrows(ScriptException.class, () -> {
+            compile("doc['nonexistent'].value * 5");
+        });
+        assertTrue(e.getCause() instanceof ParseException);
+    }
+
+    public void testFieldAccess() throws IOException {
+        TermsSetQueryScript script = compile("doc['field'].value").newInstance(null);
+        script.setDocument(1);
+
+        double result = script.execute().doubleValue();
+        assertEquals(2.718, result, 0.0);
+    }
+
+    public void testFieldAccessWithFieldAlias() throws IOException {
+        TermsSetQueryScript script = compile("doc['alias'].value").newInstance(null);
+        script.setDocument(1);
+
+        double result = script.execute().doubleValue();
+        assertEquals(2.718, result, 0.0);
+    }
+}

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

@@ -61,15 +61,24 @@ public abstract class TermsSetQueryScript {
     private final LeafSearchLookup leafLookup;
 
     public TermsSetQueryScript(Map<String, Object> params, SearchLookup lookup, LeafReaderContext leafContext) {
-        this.params = new ParameterMap(params, DEPRECATIONS);
-        this.leafLookup = lookup.getLeafSearchLookup(leafContext);
+        this.params = new ParameterMap(new HashMap<>(params), DEPRECATIONS);
+        if (leafContext == null) {
+            this.leafLookup = null;
+        } else {
+            this.leafLookup = lookup.getLeafSearchLookup(leafContext);
+            this.params.putAll(leafLookup.asMap());
+        }
+    }
+
+    protected TermsSetQueryScript() {
+        params = null;
+        leafLookup = null;
     }
 
     /**
      * Return the parameters for this script.
      */
     public Map<String, Object> getParams() {
-        this.params.putAll(leafLookup.asMap());
         return params;
     }