[ML] Include the "properties" layer in find_file_structure mappings (#62158)

Previously the "mappings" field of the response from the
find_file_structure endpoint was not a drop-in for the
mappings format of the create index endpoint - the
"properties" layer was missing.  The reason for omitting
it initially was that the assumption was that the
find_file_structure endpoint would only ever return very
simple mappings without any nested objects.  However,
this will not be true in the future, as we will improve
mappings detection for complex JSON objects.  As a first
step it makes sense to move the returned mappings closer
to the standard format.

This is a small building block towards fixing #55616

docs/reference/ml/anomaly-detection/apis/find-file-structure.asciidoc

@@ -299,21 +299,23 @@ If the request does not encounter errors, you receive the following result:
   ],
   "need_client_timezone" : true, <10>
   "mappings" : { <11>
-    "@timestamp" : {
-      "type" : "date"
-    },
-    "author" : {
-      "type" : "keyword"
-    },
-    "name" : {
-      "type" : "keyword"
-    },
-    "page_count" : {
-      "type" : "long"
-    },
-    "release_date" : {
-      "type" : "date",
-      "format" : "iso8601"
+    "properties" : {
+      "@timestamp" : {
+        "type" : "date"
+      },
+      "author" : {
+        "type" : "keyword"
+      },
+      "name" : {
+        "type" : "keyword"
+      },
+      "page_count" : {
+        "type" : "long"
+      },
+      "release_date" : {
+        "type" : "date",
+        "format" : "iso8601"
+      }
     }
   },
   "ingest_pipeline" : {
@@ -622,61 +624,63 @@ If the request does not encounter errors, you receive the following result:
   ],
   "need_client_timezone" : true, <10>
   "mappings" : {
-    "@timestamp" : {
-      "type" : "date"
-    },
-    "DOLocationID" : {
-      "type" : "long"
-    },
-    "PULocationID" : {
-      "type" : "long"
-    },
-    "RatecodeID" : {
-      "type" : "long"
-    },
-    "VendorID" : {
-      "type" : "long"
-    },
-    "extra" : {
-      "type" : "double"
-    },
-    "fare_amount" : {
-      "type" : "double"
-    },
-    "improvement_surcharge" : {
-      "type" : "double"
-    },
-    "mta_tax" : {
-      "type" : "double"
-    },
-    "passenger_count" : {
-      "type" : "long"
-    },
-    "payment_type" : {
-      "type" : "long"
-    },
-    "store_and_fwd_flag" : {
-      "type" : "keyword"
-    },
-    "tip_amount" : {
-      "type" : "double"
-    },
-    "tolls_amount" : {
-      "type" : "double"
-    },
-    "total_amount" : {
-      "type" : "double"
-    },
-    "tpep_dropoff_datetime" : {
-      "type" : "date",
-      "format" : "yyyy-MM-dd HH:mm:ss"
-    },
-    "tpep_pickup_datetime" : {
-      "type" : "date",
-      "format" : "yyyy-MM-dd HH:mm:ss"
-    },
-    "trip_distance" : {
-      "type" : "double"
+    "properties" : {
+      "@timestamp" : {
+        "type" : "date"
+      },
+      "DOLocationID" : {
+        "type" : "long"
+      },
+      "PULocationID" : {
+        "type" : "long"
+      },
+      "RatecodeID" : {
+        "type" : "long"
+      },
+      "VendorID" : {
+        "type" : "long"
+      },
+      "extra" : {
+        "type" : "double"
+      },
+      "fare_amount" : {
+        "type" : "double"
+      },
+      "improvement_surcharge" : {
+        "type" : "double"
+      },
+      "mta_tax" : {
+        "type" : "double"
+      },
+      "passenger_count" : {
+        "type" : "long"
+      },
+      "payment_type" : {
+        "type" : "long"
+      },
+      "store_and_fwd_flag" : {
+        "type" : "keyword"
+      },
+      "tip_amount" : {
+        "type" : "double"
+      },
+      "tolls_amount" : {
+        "type" : "double"
+      },
+      "total_amount" : {
+        "type" : "double"
+      },
+      "tpep_dropoff_datetime" : {
+        "type" : "date",
+        "format" : "yyyy-MM-dd HH:mm:ss"
+      },
+      "tpep_pickup_datetime" : {
+        "type" : "date",
+        "format" : "yyyy-MM-dd HH:mm:ss"
+      },
+      "trip_distance" : {
+        "type" : "double"
+      }
     }
   },
   "ingest_pipeline" : {
@@ -1560,14 +1564,16 @@ this:
   ],
   "need_client_timezone" : true,
   "mappings" : {
-    "@timestamp" : {
-      "type" : "date"
-    },
-    "loglevel" : {
-      "type" : "keyword"
-    },
-    "message" : {
-      "type" : "text"
+    "properties" : {
+      "@timestamp" : {
+        "type" : "date"
+      },
+      "loglevel" : {
+        "type" : "keyword"
+      },
+      "message" : {
+        "type" : "text"
+      }
     }
   },
   "ingest_pipeline" : {
@@ -1720,20 +1726,22 @@ this:
   ],
   "need_client_timezone" : true,
   "mappings" : {
-    "@timestamp" : {
-      "type" : "date"
-    },
-    "class" : {
-      "type" : "keyword"
-    },
-    "loglevel" : {
-      "type" : "keyword"
-    },
-    "message" : {
-      "type" : "text"
-    },
-    "node" : {
-      "type" : "keyword"
+    "properties" : {
+      "@timestamp" : {
+        "type" : "date"
+      },
+      "class" : {
+        "type" : "keyword"
+      },
+      "loglevel" : {
+        "type" : "keyword"
+      },
+      "message" : {
+        "type" : "text"
+      },
+      "node" : {
+        "type" : "keyword"
+      }
     }
   },
   "ingest_pipeline" : {

x-pack/plugin/ml/src/main/java/org/elasticsearch/xpack/ml/filestructurefinder/DelimitedFileStructureFinder.java

@@ -102,7 +102,7 @@ public class DelimitedFileStructureFinder implements FileStructureFinder {
         Tuple<SortedMap<String, Object>, SortedMap<String, FieldStats>> mappingsAndFieldStats =
             FileStructureUtils.guessMappingsAndCalculateFieldStats(explanation, sampleRecords, timeoutChecker);
 
-        SortedMap<String, Object> mappings = mappingsAndFieldStats.v1();
+        SortedMap<String, Object> fieldMappings = mappingsAndFieldStats.v1();
 
         List<String> columnNamesList = Arrays.asList(columnNames);
         char delimiter = (char) csvPreference.getDelimiterChar();
@@ -149,17 +149,17 @@ public class DelimitedFileStructureFinder implements FileStructureFinder {
                 .setJavaTimestampFormats(timeField.v2().getJavaTimestampFormats())
                 .setNeedClientTimezone(needClientTimeZone)
                 .setIngestPipeline(FileStructureUtils.makeIngestPipelineDefinition(null, Collections.emptyMap(), csvProcessorSettings,
-                    mappings, timeField.v1(), timeField.v2().getJavaTimestampFormats(), needClientTimeZone,
+                    fieldMappings, timeField.v1(), timeField.v2().getJavaTimestampFormats(), needClientTimeZone,
                     timeField.v2().needNanosecondPrecision()))
                 .setMultilineStartPattern(makeMultilineStartPattern(explanation, columnNamesList, maxLinesPerMessage, delimiterPattern,
-                    quotePattern, mappings, timeField.v1(), timeField.v2()));
+                    quotePattern, fieldMappings, timeField.v1(), timeField.v2()));
 
-            mappings.put(FileStructureUtils.DEFAULT_TIMESTAMP_FIELD, timeField.v2().getEsDateMappingTypeWithoutFormat());
+            fieldMappings.put(FileStructureUtils.DEFAULT_TIMESTAMP_FIELD, timeField.v2().getEsDateMappingTypeWithoutFormat());
         } else {
             structureBuilder.setIngestPipeline(FileStructureUtils.makeIngestPipelineDefinition(null, Collections.emptyMap(),
-                csvProcessorSettings, mappings, null, null, false, false));
+                csvProcessorSettings, fieldMappings, null, null, false, false));
             structureBuilder.setMultilineStartPattern(makeMultilineStartPattern(explanation, columnNamesList, maxLinesPerMessage,
-                delimiterPattern, quotePattern, mappings, null, null));
+                delimiterPattern, quotePattern, fieldMappings, null, null));
         }
 
         if (mappingsAndFieldStats.v2() != null) {
@@ -167,7 +167,7 @@ public class DelimitedFileStructureFinder implements FileStructureFinder {
         }
 
         FileStructure structure = structureBuilder
-            .setMappings(mappings)
+            .setMappings(Collections.singletonMap(FileStructureUtils.MAPPING_PROPERTIES_SETTING, fieldMappings))
             .setExplanation(explanation)
             .build();
 
@@ -628,7 +628,7 @@ public class DelimitedFileStructureFinder implements FileStructureFinder {
      * records.
      */
     static String makeMultilineStartPattern(List<String> explanation, List<String> columnNames, int maxLinesPerMessage,
-                                            String delimiterPattern, String quotePattern, Map<String, Object> mappings,
+                                            String delimiterPattern, String quotePattern, Map<String, Object> fieldMappings,
                                             String timeFieldName, TimestampFormatFinder timeFieldFormat) {
 
         assert columnNames.isEmpty() == false;
@@ -653,7 +653,7 @@ public class DelimitedFileStructureFinder implements FileStructureFinder {
                 explanation.add("Created a multi-line start pattern based on timestamp column [" + columnName + "]");
                 return builder.toString();
             }
-            Object columnMapping = mappings.get(columnName);
+            Object columnMapping = fieldMappings.get(columnName);
             if (columnMapping instanceof Map) {
                 String type = (String) ((Map<?, ?>) columnMapping).get(FileStructureUtils.MAPPING_TYPE_SETTING);
                 if (type != null) {

x-pack/plugin/ml/src/main/java/org/elasticsearch/xpack/ml/filestructurefinder/FileStructureUtils.java

@@ -393,6 +393,7 @@ public final class FileStructureUtils {
      * @param csvProcessorSettings The CSV processor settings for delimited formats.  <code>null</code> for
      *                             non-delimited formats.
      * @param mappingsForConversions Mappings (or partial mappings) that will be considered for field type conversions.
+     *                               The keys in the map are the top level field names - there is no properties layer.
      * @param timestampField The input field containing the timestamp to be parsed into <code>@timestamp</code>.
      *                       <code>null</code> if there is no timestamp.
      * @param timestampFormats Timestamp formats to be used for parsing {@code timestampField}.

x-pack/plugin/ml/src/main/java/org/elasticsearch/xpack/ml/filestructurefinder/NdJsonFileStructureFinder.java

@@ -71,9 +71,9 @@ public class NdJsonFileStructureFinder implements FileStructureFinder {
         Tuple<SortedMap<String, Object>, SortedMap<String, FieldStats>> mappingsAndFieldStats =
             FileStructureUtils.guessMappingsAndCalculateFieldStats(explanation, sampleRecords, timeoutChecker);
 
-        Map<String, Object> mappings = mappingsAndFieldStats.v1();
+        Map<String, Object> fieldMappings = mappingsAndFieldStats.v1();
         if (timeField != null) {
-            mappings.put(FileStructureUtils.DEFAULT_TIMESTAMP_FIELD, timeField.v2().getEsDateMappingTypeWithoutFormat());
+            fieldMappings.put(FileStructureUtils.DEFAULT_TIMESTAMP_FIELD, timeField.v2().getEsDateMappingTypeWithoutFormat());
         }
 
         if (mappingsAndFieldStats.v2() != null) {
@@ -81,7 +81,7 @@ public class NdJsonFileStructureFinder implements FileStructureFinder {
         }
 
         FileStructure structure = structureBuilder
-            .setMappings(mappings)
+            .setMappings(Collections.singletonMap(FileStructureUtils.MAPPING_PROPERTIES_SETTING, fieldMappings))
             .setExplanation(explanation)
             .build();
 

x-pack/plugin/ml/src/main/java/org/elasticsearch/xpack/ml/filestructurefinder/TextLogFileStructureFinder.java

@@ -109,15 +109,15 @@ public class TextLogFileStructureFinder implements FileStructureFinder {
             .setMultilineStartPattern(multiLineRegex);
 
         Map<String, String> messageMapping = Collections.singletonMap(FileStructureUtils.MAPPING_TYPE_SETTING, "text");
-        SortedMap<String, Object> mappings = new TreeMap<>();
-        mappings.put("message", messageMapping);
-        mappings.put(FileStructureUtils.DEFAULT_TIMESTAMP_FIELD, timestampFormatFinder.getEsDateMappingTypeWithoutFormat());
+        SortedMap<String, Object> fieldMappings = new TreeMap<>();
+        fieldMappings.put("message", messageMapping);
+        fieldMappings.put(FileStructureUtils.DEFAULT_TIMESTAMP_FIELD, timestampFormatFinder.getEsDateMappingTypeWithoutFormat());
 
         SortedMap<String, FieldStats> fieldStats = new TreeMap<>();
         fieldStats.put("message", FileStructureUtils.calculateFieldStats(messageMapping, sampleMessages, timeoutChecker));
 
         Map<String, String> customGrokPatternDefinitions = timestampFormatFinder.getCustomGrokPatternDefinitions();
-        GrokPatternCreator grokPatternCreator = new GrokPatternCreator(explanation, sampleMessages, mappings, fieldStats,
+        GrokPatternCreator grokPatternCreator = new GrokPatternCreator(explanation, sampleMessages, fieldMappings, fieldStats,
             customGrokPatternDefinitions, timeoutChecker);
         // We can't parse directly into @timestamp using Grok, so parse to some other time field, which the date filter will then remove
         String interimTimestampField = overrides.getTimestampField();
@@ -150,10 +150,10 @@ public class TextLogFileStructureFinder implements FileStructureFinder {
             .setJavaTimestampFormats(timestampFormatFinder.getJavaTimestampFormats())
             .setNeedClientTimezone(needClientTimeZone)
             .setGrokPattern(grokPattern)
-            .setIngestPipeline(FileStructureUtils.makeIngestPipelineDefinition(grokPattern, customGrokPatternDefinitions, null, mappings,
-                interimTimestampField, timestampFormatFinder.getJavaTimestampFormats(), needClientTimeZone,
+            .setIngestPipeline(FileStructureUtils.makeIngestPipelineDefinition(grokPattern, customGrokPatternDefinitions, null,
+                fieldMappings, interimTimestampField, timestampFormatFinder.getJavaTimestampFormats(), needClientTimeZone,
                 timestampFormatFinder.needNanosecondPrecision()))
-            .setMappings(mappings)
+            .setMappings(Collections.singletonMap(FileStructureUtils.MAPPING_PROPERTIES_SETTING, fieldMappings))
             .setFieldStats(fieldStats)
             .setExplanation(explanation)
             .build();

x-pack/plugin/ml/src/main/java/org/elasticsearch/xpack/ml/filestructurefinder/XmlFileStructureFinder.java

@@ -114,18 +114,18 @@ public class XmlFileStructureFinder implements FileStructureFinder {
             structureBuilder.setFieldStats(mappingsAndFieldStats.v2());
         }
 
-        Map<String, Object> innerMappings = mappingsAndFieldStats.v1();
+        Map<String, Object> innerFieldMappings = mappingsAndFieldStats.v1();
         Map<String, Object> secondLevelProperties = new LinkedHashMap<>();
         secondLevelProperties.put(FileStructureUtils.MAPPING_TYPE_SETTING, "object");
-        secondLevelProperties.put(FileStructureUtils.MAPPING_PROPERTIES_SETTING, innerMappings);
-        SortedMap<String, Object> outerMappings = new TreeMap<>();
-        outerMappings.put(topLevelTag, secondLevelProperties);
+        secondLevelProperties.put(FileStructureUtils.MAPPING_PROPERTIES_SETTING, innerFieldMappings);
+        SortedMap<String, Object> outerFieldMappings = new TreeMap<>();
+        outerFieldMappings.put(topLevelTag, secondLevelProperties);
         if (timeField != null) {
-            outerMappings.put(FileStructureUtils.DEFAULT_TIMESTAMP_FIELD, timeField.v2().getEsDateMappingTypeWithoutFormat());
+            outerFieldMappings.put(FileStructureUtils.DEFAULT_TIMESTAMP_FIELD, timeField.v2().getEsDateMappingTypeWithoutFormat());
         }
 
         FileStructure structure = structureBuilder
-            .setMappings(outerMappings)
+            .setMappings(Collections.singletonMap(FileStructureUtils.MAPPING_PROPERTIES_SETTING, outerFieldMappings))
             .setExplanation(explanation)
             .build();
 

x-pack/plugin/ml/src/test/java/org/elasticsearch/xpack/ml/filestructurefinder/DelimitedFileStructureFinderTests.java

@@ -30,8 +30,8 @@ import static org.hamcrest.Matchers.not;
 
 public class DelimitedFileStructureFinderTests extends FileStructureTestCase {
 
-    private FileStructureFinderFactory csvFactory = new DelimitedFileStructureFinderFactory(',', '"', 2, false);
-    private FileStructureFinderFactory tsvFactory = new DelimitedFileStructureFinderFactory('\t', '"', 3, false);
+    private final FileStructureFinderFactory csvFactory = new DelimitedFileStructureFinderFactory(',', '"', 2, false);
+    private final FileStructureFinderFactory tsvFactory = new DelimitedFileStructureFinderFactory('\t', '"', 3, false);
 
     public void testCreateConfigsGivenCompleteCsv() throws Exception {
         String sample = "time,message\n" +
@@ -63,6 +63,7 @@ public class DelimitedFileStructureFinderTests extends FileStructureTestCase {
         assertNull(structure.getGrokPattern());
         assertEquals("time", structure.getTimestampField());
         assertEquals(Collections.singletonList("ISO8601"), structure.getJodaTimestampFormats());
+        assertEquals(Collections.singleton("properties"), structure.getMappings().keySet());
     }
 
     public void testCreateConfigsGivenIncompleteCsv() throws Exception {
@@ -109,6 +110,7 @@ public class DelimitedFileStructureFinderTests extends FileStructureTestCase {
         assertNull(structure.getMultilineStartPattern());
         assertNull(structure.getShouldTrimFields());
         assertNull(structure.getGrokPattern());
+        assertEquals(Collections.singleton("properties"), structure.getMappings().keySet());
     }
 
     public void testCreateConfigsGivenIncompleteCsvWithMultiLinedRows() throws Exception {
@@ -156,6 +158,7 @@ public class DelimitedFileStructureFinderTests extends FileStructureTestCase {
         assertEquals("^\"?\\d{4}-\\d{2}-\\d{2}[T ]\\d{2}:\\d{2}", structure.getMultilineStartPattern());
         assertNull(structure.getShouldTrimFields());
         assertNull(structure.getGrokPattern());
+        assertEquals(Collections.singleton("properties"), structure.getMappings().keySet());
     }
 
     public void testCreateConfigsGivenCompleteCsvAndColumnNamesOverride() throws Exception {
@@ -191,6 +194,7 @@ public class DelimitedFileStructureFinderTests extends FileStructureTestCase {
         assertNull(structure.getGrokPattern());
         assertEquals("my_time", structure.getTimestampField());
         assertEquals(Collections.singletonList("ISO8601"), structure.getJodaTimestampFormats());
+        assertEquals(Collections.singleton("properties"), structure.getMappings().keySet());
     }
 
     public void testCreateConfigsGivenCompleteCsvAndHasHeaderRowOverride() throws Exception {
@@ -228,6 +232,7 @@ public class DelimitedFileStructureFinderTests extends FileStructureTestCase {
         assertNull(structure.getGrokPattern());
         assertNull(structure.getTimestampField());
         assertNull(structure.getJodaTimestampFormats());
+        assertEquals(Collections.singleton("properties"), structure.getMappings().keySet());
     }
 
     public void testCreateConfigsGivenCsvWithIncompleteLastRecord() throws Exception {
@@ -261,6 +266,7 @@ public class DelimitedFileStructureFinderTests extends FileStructureTestCase {
         assertNull(structure.getGrokPattern());
         assertEquals("time", structure.getTimestampField());
         assertEquals(Collections.singletonList("ISO8601"), structure.getJodaTimestampFormats());
+        assertEquals(Collections.singleton("properties"), structure.getMappings().keySet());
     }
 
     public void testCreateConfigsGivenCsvWithTrailingNulls() throws Exception {
@@ -301,6 +307,7 @@ public class DelimitedFileStructureFinderTests extends FileStructureTestCase {
         assertNull(structure.getGrokPattern());
         assertEquals("tpep_pickup_datetime", structure.getTimestampField());
         assertEquals(Collections.singletonList("YYYY-MM-dd HH:mm:ss"), structure.getJodaTimestampFormats());
+        assertEquals(Collections.singleton("properties"), structure.getMappings().keySet());
     }
 
     public void testCreateConfigsGivenCsvWithTrailingNullsAndOverriddenTimeField() throws Exception {
@@ -346,6 +353,7 @@ public class DelimitedFileStructureFinderTests extends FileStructureTestCase {
         assertNull(structure.getGrokPattern());
         assertEquals("tpep_dropoff_datetime", structure.getTimestampField());
         assertEquals(Collections.singletonList("YYYY-MM-dd HH:mm:ss"), structure.getJodaTimestampFormats());
+        assertEquals(Collections.singleton("properties"), structure.getMappings().keySet());
     }
 
     public void testCreateConfigsGivenCsvWithTrailingNullsExceptHeader() throws Exception {
@@ -386,6 +394,7 @@ public class DelimitedFileStructureFinderTests extends FileStructureTestCase {
         assertNull(structure.getGrokPattern());
         assertEquals("tpep_pickup_datetime", structure.getTimestampField());
         assertEquals(Collections.singletonList("YYYY-MM-dd HH:mm:ss"), structure.getJodaTimestampFormats());
+        assertEquals(Collections.singleton("properties"), structure.getMappings().keySet());
     }
 
     public void testCreateConfigsGivenCsvWithTrailingNullsExceptHeaderAndColumnNamesOverride() throws Exception {
@@ -434,6 +443,7 @@ public class DelimitedFileStructureFinderTests extends FileStructureTestCase {
         assertNull(structure.getGrokPattern());
         assertEquals("my_tpep_pickup_datetime", structure.getTimestampField());
         assertEquals(Collections.singletonList("YYYY-MM-dd HH:mm:ss"), structure.getJodaTimestampFormats());
+        assertEquals(Collections.singleton("properties"), structure.getMappings().keySet());
     }
 
     public void testCreateConfigsGivenCsvWithTimeLastColumn() throws Exception {
@@ -467,6 +477,7 @@ public class DelimitedFileStructureFinderTests extends FileStructureTestCase {
         assertNull(structure.getGrokPattern());
         assertEquals("timestamp", structure.getTimestampField());
         assertEquals(Collections.singletonList("YYYY-MM-dd HH:mm:ss.SSSSSS"), structure.getJodaTimestampFormats());
+        assertEquals(Collections.singleton("properties"), structure.getMappings().keySet());
     }
 
     public void testCreateConfigsGivenTsvWithSyslogLikeTimestamp() throws Exception {
@@ -508,6 +519,7 @@ public class DelimitedFileStructureFinderTests extends FileStructureTestCase {
         assertEquals("Timestamp", structure.getTimestampField());
         assertEquals(Arrays.asList("MMM dd YYYY HH:mm:ss", "MMM  d YYYY HH:mm:ss", "MMM d YYYY HH:mm:ss"),
             structure.getJodaTimestampFormats());
+        assertEquals(Collections.singleton("properties"), structure.getMappings().keySet());
     }
 
     public void testCreateConfigsGivenDotInFieldName() throws Exception {
@@ -541,6 +553,7 @@ public class DelimitedFileStructureFinderTests extends FileStructureTestCase {
         assertNull(structure.getGrokPattern());
         assertEquals("time_iso8601", structure.getTimestampField());
         assertEquals(Collections.singletonList("ISO8601"), structure.getJodaTimestampFormats());
+        assertEquals(Collections.singleton("properties"), structure.getMappings().keySet());
     }
 
     public void testFindHeaderFromSampleGivenHeaderInSample() throws IOException {

x-pack/plugin/ml/src/test/java/org/elasticsearch/xpack/ml/filestructurefinder/NdJsonFileStructureFinderTests.java

@@ -11,7 +11,7 @@ import java.util.Collections;
 
 public class NdJsonFileStructureFinderTests extends FileStructureTestCase {
 
-    private FileStructureFinderFactory factory = new NdJsonFileStructureFinderFactory();
+    private final FileStructureFinderFactory factory = new NdJsonFileStructureFinderFactory();
 
     public void testCreateConfigsGivenGoodJson() throws Exception {
         assertTrue(factory.canCreateFromSample(explanation, NDJSON_SAMPLE, 0.0));
@@ -39,5 +39,6 @@ public class NdJsonFileStructureFinderTests extends FileStructureTestCase {
         assertNull(structure.getGrokPattern());
         assertEquals("timestamp", structure.getTimestampField());
         assertEquals(Collections.singletonList("UNIX_MS"), structure.getJodaTimestampFormats());
+        assertEquals(Collections.singleton("properties"), structure.getMappings().keySet());
     }
 }

x-pack/plugin/ml/src/test/java/org/elasticsearch/xpack/ml/filestructurefinder/TextLogFileStructureFinderTests.java

@@ -18,7 +18,7 @@ import static org.hamcrest.Matchers.not;
 
 public class TextLogFileStructureFinderTests extends FileStructureTestCase {
 
-    private FileStructureFinderFactory factory = new TextLogFileStructureFinderFactory();
+    private final FileStructureFinderFactory factory = new TextLogFileStructureFinderFactory();
 
     public void testCreateConfigsGivenLowLineMergeSizeLimit() {
 
@@ -74,6 +74,7 @@ public class TextLogFileStructureFinderTests extends FileStructureTestCase {
         for (String statMessage : messageFieldStats.getTopHits().stream().map(m -> (String) m.get("value")).collect(Collectors.toList())) {
             assertThat(structureFinder.getSampleMessages(), hasItem(statMessage));
         }
+        assertEquals(Collections.singleton("properties"), structure.getMappings().keySet());
     }
 
     public void testCreateConfigsGivenElasticsearchLogAndTimestampFormatOverride() throws Exception {
@@ -115,6 +116,7 @@ public class TextLogFileStructureFinderTests extends FileStructureTestCase {
         for (String statMessage : messageFieldStats.getTopHits().stream().map(m -> (String) m.get("value")).collect(Collectors.toList())) {
             assertThat(structureFinder.getSampleMessages(), hasItem(statMessage));
         }
+        assertEquals(Collections.singleton("properties"), structure.getMappings().keySet());
     }
 
     public void testCreateConfigsGivenElasticsearchLogAndTimestampFieldOverride() throws Exception {
@@ -151,6 +153,7 @@ public class TextLogFileStructureFinderTests extends FileStructureTestCase {
         for (String statMessage : messageFieldStats.getTopHits().stream().map(m -> (String) m.get("value")).collect(Collectors.toList())) {
             assertThat(structureFinder.getSampleMessages(), hasItem(statMessage));
         }
+        assertEquals(Collections.singleton("properties"), structure.getMappings().keySet());
     }
 
     public void testCreateConfigsGivenElasticsearchLogAndGrokPatternOverride() throws Exception {
@@ -191,6 +194,7 @@ public class TextLogFileStructureFinderTests extends FileStructureTestCase {
             // at the end of the processing will _not_ contain a complete sample message
             assertThat(structureFinder.getSampleMessages(), not(hasItem(statMessage)));
         }
+        assertEquals(Collections.singleton("properties"), structure.getMappings().keySet());
     }
 
     public void testCreateConfigsGivenElasticsearchLogAndImpossibleGrokPatternOverride() {

x-pack/plugin/ml/src/test/java/org/elasticsearch/xpack/ml/filestructurefinder/XmlFileStructureFinderTests.java

@@ -11,7 +11,7 @@ import java.util.Collections;
 
 public class XmlFileStructureFinderTests extends FileStructureTestCase {
 
-    private FileStructureFinderFactory factory = new XmlFileStructureFinderFactory();
+    private final FileStructureFinderFactory factory = new XmlFileStructureFinderFactory();
 
     public void testCreateConfigsGivenGoodXml() throws Exception {
         assertTrue(factory.canCreateFromSample(explanation, XML_SAMPLE, 0.0));
@@ -39,5 +39,6 @@ public class XmlFileStructureFinderTests extends FileStructureTestCase {
         assertNull(structure.getGrokPattern());
         assertEquals("timestamp", structure.getTimestampField());
         assertEquals(Collections.singletonList("UNIX_MS"), structure.getJodaTimestampFormats());
+        assertEquals(Collections.singleton("properties"), structure.getMappings().keySet());
     }
 }

x-pack/plugin/src/test/resources/rest-api-spec/test/ml/find_file_structure.yml

@@ -35,11 +35,11 @@ setup:
   - match: { joda_timestamp_formats.0: UNIX }
   - match: { java_timestamp_formats.0: UNIX }
   - match: { need_client_timezone: false }
-  - match: { mappings.airline.type: keyword }
-  - match: { mappings.responsetime.type: double }
-  - match: { mappings.sourcetype.type: keyword }
-  - match: { mappings.time.type: date }
-  - match: { mappings.time.format: epoch_second }
+  - match: { mappings.properties.airline.type: keyword }
+  - match: { mappings.properties.responsetime.type: double }
+  - match: { mappings.properties.sourcetype.type: keyword }
+  - match: { mappings.properties.time.type: date }
+  - match: { mappings.properties.time.format: epoch_second }
   - match: { ingest_pipeline.description: "Ingest pipeline created by file structure finder" }
   - match: { ingest_pipeline.processors.0.date.field: time }
   - match: { ingest_pipeline.processors.0.date.formats.0: UNIX }
@@ -96,11 +96,11 @@ setup:
   - match: { joda_timestamp_formats.0: UNIX }
   - match: { java_timestamp_formats.0: UNIX }
   - match: { need_client_timezone: false }
-  - match: { mappings.airline.type: keyword }
-  - match: { mappings.responsetime.type: double }
-  - match: { mappings.sourcetype.type: keyword }
-  - match: { mappings.time.type: date }
-  - match: { mappings.time.format: epoch_second }
+  - match: { mappings.properties.airline.type: keyword }
+  - match: { mappings.properties.responsetime.type: double }
+  - match: { mappings.properties.sourcetype.type: keyword }
+  - match: { mappings.properties.time.type: date }
+  - match: { mappings.properties.time.format: epoch_second }
   - match: { ingest_pipeline.description: "Ingest pipeline created by file structure finder" }
   - match: { ingest_pipeline.processors.0.date.field: time }
   - match: { ingest_pipeline.processors.0.date.formats.0: UNIX }