Script: Reindex & UpdateByQuery Metadata (#88665)

Adds metadata classes for Reindex and UpdateByQuery contexts.

For Reindex metadata:
 * _index can't be null
 * _id, _routing and _version are writable and nullable
 * _now is read-only
 * op is read-write must be 'noop', 'index' or 'delete'

Reindex metadata keeps the originx value for _index, _id, _routing and _version
so that `Reindexer` can see if they've changed.

If _version is null in the ctx map, or, equivalently, the augmentation
`setVersionToInternal()` was called by the script, `Reindexer` sets document
versioning to internal.  If `_version` is `null` in the ctx map, `getVersion`
returns `Long.MIN_VALUE`.

For UpdateByQuery metadata:
 * _index, _id, _version, _routing are all read-only
 * _routing is also nullable
 * _now is read-only
 * op is read-write and one of 'index', 'noop', 'delete'

Closes: #86472

Author: stu-elastic

docs/changelog/88665.yaml

@@ -0,0 +1,5 @@
+pr: 88665
+summary: "Script: Reindex & `UpdateByQuery` Metadata"
+area: Infra/Scripting
+type: enhancement
+issues: []

modules/lang-painless/src/main/resources/org/elasticsearch/painless/org.elasticsearch.script.reindex.txt

@@ -18,3 +18,22 @@ class org.elasticsearch.painless.api.Json {
   String dump(def)
   String dump(def, boolean)
 }
+
+class org.elasticsearch.script.Metadata {
+    String getIndex()
+    void setIndex(String)
+    String getId()
+    void setId(String)
+    String getRouting()
+    void setRouting(String)
+    long getVersion()
+    void setVersion(long)
+    boolean org.elasticsearch.script.ReindexMetadata isVersionInternal()
+    void org.elasticsearch.script.ReindexMetadata setVersionToInternal()
+    String getOp()
+    void setOp(String)
+}
+
+class org.elasticsearch.script.ReindexScript {
+    Metadata metadata()
+}

modules/lang-painless/src/main/resources/org/elasticsearch/painless/org.elasticsearch.script.update_by_query.txt

@@ -18,3 +18,16 @@ class org.elasticsearch.painless.api.Json {
   String dump(def)
   String dump(def, boolean)
 }
+
+class org.elasticsearch.script.Metadata {
+    String getIndex()
+    String getId()
+    String getRouting()
+    long getVersion()
+    String getOp()
+    void setOp(String)
+}
+
+class org.elasticsearch.script.UpdateByQueryScript {
+    Metadata metadata()
+}

modules/reindex/build.gradle

@@ -178,3 +178,12 @@ tasks.named("yamlRestTestV7CompatTransform").configure { task ->
 
     task.addAllowedWarningRegex("\\[types removal\\].*")
 }
+
+tasks.named("yamlRestTestV7CompatTest").configure {
+  systemProperty 'tests.rest.blacklist', [
+    'update_by_query/80_scripting/Can\'t change _id',
+    'update_by_query/80_scripting/Set unsupported operation type',
+    'update_by_query/80_scripting/Setting bogus context is an error',
+
+  ].join(',')
+}

modules/reindex/src/main/java/org/elasticsearch/reindex/AbstractAsyncBulkByScrollAction.java

@@ -30,18 +30,15 @@
 import org.elasticsearch.core.Nullable;
 import org.elasticsearch.core.TimeValue;
 import org.elasticsearch.index.VersionType;
-import org.elasticsearch.index.mapper.IdFieldMapper;
-import org.elasticsearch.index.mapper.IndexFieldMapper;
-import org.elasticsearch.index.mapper.RoutingFieldMapper;
-import org.elasticsearch.index.mapper.SourceFieldMapper;
-import org.elasticsearch.index.mapper.VersionFieldMapper;
 import org.elasticsearch.index.reindex.AbstractBulkByScrollRequest;
 import org.elasticsearch.index.reindex.BulkByScrollResponse;
 import org.elasticsearch.index.reindex.BulkByScrollTask;
 import org.elasticsearch.index.reindex.ClientScrollableHitSource;
 import org.elasticsearch.index.reindex.ScrollableHitSource;
 import org.elasticsearch.index.reindex.ScrollableHitSource.SearchFailure;
 import org.elasticsearch.index.reindex.WorkerBulkByScrollTaskState;
+import org.elasticsearch.script.CtxMap;
+import org.elasticsearch.script.Metadata;
 import org.elasticsearch.script.Script;
 import org.elasticsearch.script.ScriptService;
 import org.elasticsearch.search.Scroll;
@@ -50,20 +47,18 @@
 import org.elasticsearch.threadpool.ThreadPool;
 
 import java.util.ArrayList;
-import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
-import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
-import java.util.Locale;
 import java.util.Map;
 import java.util.Objects;
 import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.atomic.AtomicLong;
 import java.util.function.BiFunction;
+import java.util.function.LongSupplier;
 
 import static java.lang.Math.max;
 import static java.lang.Math.min;
@@ -819,147 +814,73 @@ public static RequestWrapper<DeleteRequest> wrap(DeleteRequest request) {
     /**
      * Apply a {@link Script} to a {@link RequestWrapper}
      */
-    public abstract static class ScriptApplier implements BiFunction<RequestWrapper<?>, ScrollableHitSource.Hit, RequestWrapper<?>> {
+    public abstract static class ScriptApplier<T extends Metadata>
+        implements
+            BiFunction<RequestWrapper<?>, ScrollableHitSource.Hit, RequestWrapper<?>> {
+
+        // "index" is the default operation
+        protected static final String INDEX = "index";
 
         private final WorkerBulkByScrollTaskState taskWorker;
         protected final ScriptService scriptService;
         protected final Script script;
         protected final Map<String, Object> params;
+        protected final LongSupplier nowInMillisSupplier;
 
         public ScriptApplier(
             WorkerBulkByScrollTaskState taskWorker,
             ScriptService scriptService,
             Script script,
-            Map<String, Object> params
+            Map<String, Object> params,
+            LongSupplier nowInMillisSupplier
         ) {
             this.taskWorker = taskWorker;
             this.scriptService = scriptService;
             this.script = script;
             this.params = params;
+            this.nowInMillisSupplier = nowInMillisSupplier;
         }
 
         @Override
-        @SuppressWarnings("unchecked")
         public RequestWrapper<?> apply(RequestWrapper<?> request, ScrollableHitSource.Hit doc) {
             if (script == null) {
                 return request;
             }
 
-            Map<String, Object> context = new HashMap<>();
-            context.put(IndexFieldMapper.NAME, doc.getIndex());
-            context.put(IdFieldMapper.NAME, doc.getId());
-            Long oldVersion = doc.getVersion();
-            context.put(VersionFieldMapper.NAME, oldVersion);
-            String oldRouting = doc.getRouting();
-            context.put(RoutingFieldMapper.NAME, oldRouting);
-            context.put(SourceFieldMapper.NAME, request.getSource());
-
-            OpType oldOpType = OpType.INDEX;
-            context.put("op", oldOpType.toString());
+            CtxMap<T> ctxMap = execute(doc, request.getSource());
 
-            execute(context);
+            T metadata = ctxMap.getMetadata();
 
-            String newOp = (String) context.remove("op");
-            if (newOp == null) {
-                throw new IllegalArgumentException("Script cleared operation type");
-            }
+            request.setSource(ctxMap.getSource());
 
-            /*
-             * It'd be lovely to only set the source if we know its been modified
-             * but it isn't worth keeping two copies of it around just to check!
-             */
-            request.setSource((Map<String, Object>) context.remove(SourceFieldMapper.NAME));
+            updateRequest(request, metadata);
 
-            Object newValue = context.remove(IndexFieldMapper.NAME);
-            if (false == doc.getIndex().equals(newValue)) {
-                scriptChangedIndex(request, newValue);
-            }
-            newValue = context.remove(IdFieldMapper.NAME);
-            if (false == doc.getId().equals(newValue)) {
-                scriptChangedId(request, newValue);
-            }
-            newValue = context.remove(VersionFieldMapper.NAME);
-            if (false == Objects.equals(oldVersion, newValue)) {
-                scriptChangedVersion(request, newValue);
-            }
-            /*
-             * Its important that routing comes after parent in case you want to
-             * change them both.
-             */
-            newValue = context.remove(RoutingFieldMapper.NAME);
-            if (false == Objects.equals(oldRouting, newValue)) {
-                scriptChangedRouting(request, newValue);
-            }
+            return requestFromOp(request, metadata.getOp());
+        }
 
-            OpType newOpType = OpType.fromString(newOp);
-            if (newOpType != oldOpType) {
-                return scriptChangedOpType(request, oldOpType, newOpType);
-            }
+        protected abstract CtxMap<T> execute(ScrollableHitSource.Hit doc, Map<String, Object> source);
 
-            if (false == context.isEmpty()) {
-                throw new IllegalArgumentException("Invalid fields added to context [" + String.join(",", context.keySet()) + ']');
-            }
-            return request;
-        }
+        protected abstract void updateRequest(RequestWrapper<?> request, T metadata);
 
-        protected RequestWrapper<?> scriptChangedOpType(RequestWrapper<?> request, OpType oldOpType, OpType newOpType) {
-            switch (newOpType) {
-                case NOOP -> {
+        protected RequestWrapper<?> requestFromOp(RequestWrapper<?> request, String op) {
+            switch (op) {
+                case "noop" -> {
                     taskWorker.countNoop();
                     return null;
                 }
-                case DELETE -> {
+                case "delete" -> {
                     RequestWrapper<DeleteRequest> delete = wrap(new DeleteRequest(request.getIndex(), request.getId()));
                     delete.setVersion(request.getVersion());
                     delete.setVersionType(VersionType.INTERNAL);
                     delete.setRouting(request.getRouting());
                     return delete;
                 }
-                default -> throw new IllegalArgumentException(
-                    "Unsupported operation type change from [" + oldOpType + "] to [" + newOpType + "]"
-                );
+                case INDEX -> {
+                    return request;
+                }
+                default -> throw new IllegalArgumentException("Unsupported operation type change from [" + INDEX + "] to [" + op + "]");
             }
         }
-
-        protected abstract void scriptChangedIndex(RequestWrapper<?> request, Object to);
-
-        protected abstract void scriptChangedId(RequestWrapper<?> request, Object to);
-
-        protected abstract void scriptChangedVersion(RequestWrapper<?> request, Object to);
-
-        protected abstract void scriptChangedRouting(RequestWrapper<?> request, Object to);
-
-        protected abstract void execute(Map<String, Object> ctx);
-    }
-
-    public enum OpType {
-
-        NOOP("noop"),
-        INDEX("index"),
-        DELETE("delete");
-
-        private final String id;
-
-        OpType(String id) {
-            this.id = id;
-        }
-
-        public static OpType fromString(String opType) {
-            String lowerOpType = opType.toLowerCase(Locale.ROOT);
-            return switch (lowerOpType) {
-                case "noop" -> OpType.NOOP;
-                case "index" -> OpType.INDEX;
-                case "delete" -> OpType.DELETE;
-                default -> throw new IllegalArgumentException(
-                    "Operation type [" + lowerOpType + "] not allowed, only " + Arrays.toString(values()) + " are allowed"
-                );
-            };
-        }
-
-        @Override
-        public String toString() {
-            return id.toLowerCase(Locale.ROOT);
-        }
     }
 
     static class ScrollConsumableHitsResponse {