Runtime field: test currentTimeMillis

Adds a test for `runtime_script` who's script contains
`currentTimeMillis`.

Author: nik9000

x-pack/plugin/runtime-fields/src/test/java/org/elasticsearch/xpack/runtimefields/mapper/ScriptDateMappedFieldTypeTests.java

@@ -13,6 +13,7 @@
 import org.apache.lucene.index.SortedNumericDocValues;
 import org.apache.lucene.search.Collector;
 import org.apache.lucene.search.Explanation;
+import org.apache.lucene.search.FieldDoc;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.LeafCollector;
 import org.apache.lucene.search.MatchAllDocsQuery;
@@ -152,6 +153,9 @@ public void testSort() throws IOException {
                 assertThat(readSource(reader, docs.scoreDocs[0].doc), equalTo("{\"timestamp\": [1595432181351]}"));
                 assertThat(readSource(reader, docs.scoreDocs[1].doc), equalTo("{\"timestamp\": [1595432181354]}"));
                 assertThat(readSource(reader, docs.scoreDocs[2].doc), equalTo("{\"timestamp\": [1595432181356]}"));
+                assertThat((Long) (((FieldDoc) docs.scoreDocs[0]).fields[0]), equalTo(1595432181351L));
+                assertThat((Long) (((FieldDoc) docs.scoreDocs[1]).fields[0]), equalTo(1595432181354L));
+                assertThat((Long) (((FieldDoc) docs.scoreDocs[2]).fields[0]), equalTo(1595432181356L));
             }
         }
     }

x-pack/plugin/runtime-fields/src/test/java/org/elasticsearch/xpack/runtimefields/mapper/ScriptLongMappedFieldTypeTests.java

@@ -12,6 +12,7 @@
 import org.apache.lucene.index.RandomIndexWriter;
 import org.apache.lucene.index.SortedNumericDocValues;
 import org.apache.lucene.search.Collector;
+import org.apache.lucene.search.FieldDoc;
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.LeafCollector;
 import org.apache.lucene.search.MatchAllDocsQuery;
@@ -52,6 +53,7 @@
 
 import static java.util.Collections.emptyMap;
 import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.greaterThan;
 
 public class ScriptLongMappedFieldTypeTests extends AbstractNonTextScriptMappedFieldTypeTestCase {
     public void testFormat() throws IOException {
@@ -117,6 +119,30 @@ public void testSort() throws IOException {
         }
     }
 
+    public void testNow() throws IOException {
+        try (Directory directory = newDirectory(); RandomIndexWriter iw = new RandomIndexWriter(random(), directory)) {
+            iw.addDocument(List.of(new StoredField("_source", new BytesRef("{\"timestamp\": [1595432181354]}"))));
+            iw.addDocument(List.of(new StoredField("_source", new BytesRef("{\"timestamp\": [1595432181351]}"))));
+            iw.addDocument(List.of(new StoredField("_source", new BytesRef("{\"timestamp\": [1595432181356]}"))));
+            try (DirectoryReader reader = iw.getReader()) {
+                IndexSearcher searcher = newSearcher(reader);
+                ScriptLongFieldData ifd = build("millis_ago", Map.of()).fielddataBuilder("test", mockContext()::lookup)
+                    .build(null, null, null);
+                SortField sf = ifd.sortField(null, MultiValueMode.MIN, null, false);
+                TopFieldDocs docs = searcher.search(new MatchAllDocsQuery(), 3, new Sort(sf));
+                assertThat(readSource(reader, docs.scoreDocs[0].doc), equalTo("{\"timestamp\": [1595432181356]}"));
+                assertThat(readSource(reader, docs.scoreDocs[1].doc), equalTo("{\"timestamp\": [1595432181354]}"));
+                assertThat(readSource(reader, docs.scoreDocs[2].doc), equalTo("{\"timestamp\": [1595432181351]}"));
+                long t1 = (Long) (((FieldDoc) docs.scoreDocs[0]).fields[0]);
+                assertThat(t1, greaterThan(3638011399L));
+                long t2 = (Long) (((FieldDoc) docs.scoreDocs[1]).fields[0]);
+                long t3 = (Long) (((FieldDoc) docs.scoreDocs[2]).fields[0]);
+                assertThat(t2, equalTo(t1 + 2));
+                assertThat(t3, equalTo(t1 + 5));
+            }
+        }
+    }
+
     @Override
     public void testUsedInScript() throws IOException {
         try (Directory directory = newDirectory(); RandomIndexWriter iw = new RandomIndexWriter(random(), directory)) {
@@ -290,6 +316,17 @@ public void execute() {
                                         }
                                     }
                                 };
+                            case "millis_ago":
+                                // Painless actually call System.currentTimeMillis. We could mock the time but this works fine too.
+                                long now = System.currentTimeMillis();
+                                return (params, lookup) -> (ctx) -> new LongScriptFieldScript(params, lookup, ctx) {
+                                    @Override
+                                    public void execute() {
+                                        for (Object timestamp : (List<?>) getSource().get("timestamp")) {
+                                            emitValue(now - ((Number) timestamp).longValue());
+                                        }
+                                    }
+                                };
                             default:
                                 throw new IllegalArgumentException("unsupported script [" + code + "]");
                         }

x-pack/plugin/src/test/resources/rest-api-spec/test/runtime_fields/20_long.yml

@@ -49,6 +49,15 @@ setup:
                         t /= 10;
                       }
                     }
+              # Test now
+              millis_ago:
+                type: runtime_script
+                runtime_type: date
+                script:
+                  source: |
+                    for (def dt : doc['timestamp']) {
+                      emitValue(System.currentTimeMillis() - dt.toInstant().toEpochMilli());
+                    }
 
   - do:
       bulk:
@@ -90,7 +99,12 @@ setup:
         index: sensor
         body:
           sort: timestamp
-          docvalue_fields: [voltage_times_ten, voltage_times_ten_from_source, temperature_digits]
+          docvalue_fields:
+            - voltage_times_ten
+            - voltage_times_ten_from_source
+            - temperature_digits
+            - field: millis_ago
+              format: epoch_millis
   - match: {hits.total.value: 6}
   - match: {hits.hits.0.fields.voltage_times_ten: [40] }
   - match: {hits.hits.0.fields.voltage_times_ten_from_source: [40] }
@@ -101,6 +115,8 @@ setup:
   - match: {hits.hits.3.fields.voltage_times_ten: [51] }
   - match: {hits.hits.4.fields.voltage_times_ten: [58] }
   - match: {hits.hits.5.fields.voltage_times_ten: [52] }
+  # We can't check the value because it is constantly increasing. If `gt` worked on strings we could do it, but it doens't.
+  - is_true: hits.hits.0.fields.millis_ago.0
 
 ---
 "terms agg":
@@ -223,3 +239,4 @@ setup:
   - match: { aggregations.to-users.users.hits.hits.2._index: test }
   - match: { aggregations.to-users.users.hits.hits.2._nested.field: users }
   - match: { aggregations.to-users.users.hits.hits.2._nested.offset: 1 }
+