Add support for a 'format' option in fields retrieval. (#57855)

The new `format` option allows for passing a custom date format:

```
POST logs-*/_search
{
  "fields": [
    "file.*",
    {
      "field": "event.timestamp",
      "format": "epoch_millis"
    },
    ...
  ]
}
```

Other API notes:
* We use the same syntax as `docvalue_fields` for consistency. Under the hood,
both `fields` and `docvalue_fields` use the same `FieldAndFormat` object to
share serialization logic.
* Only `date` and `date_range` fields support formatting currently.

Author: jtibshirani

modules/mapper-extras/src/main/java/org/elasticsearch/index/mapper/RankFeatureFieldMapper.java

@@ -181,7 +181,10 @@ private Float objectToFloat(Object value) {
     }
 
     @Override
-    protected Float parseSourceValue(Object value) {
+    protected Float parseSourceValue(Object value, String format) {
+        if (format != null) {
+            throw new IllegalArgumentException("Field [" + name() + "] of type [" + typeName() + "] doesn't support formats.");
+        }
         return objectToFloat(value);
     }
 

modules/mapper-extras/src/main/java/org/elasticsearch/index/mapper/RankFeaturesFieldMapper.java

@@ -160,7 +160,10 @@ protected void parseCreateField(ParseContext context) throws IOException {
     }
 
     @Override
-    protected Object parseSourceValue(Object value) {
+    protected Object parseSourceValue(Object value, String format) {
+        if (format != null) {
+            throw new IllegalArgumentException("Field [" + name() + "] of type [" + typeName() + "] doesn't support formats.");
+        }
         return value;
     }
 

modules/mapper-extras/src/main/java/org/elasticsearch/index/mapper/ScaledFloatFieldMapper.java

@@ -473,7 +473,11 @@ private static double objectToDouble(Object value) {
     }
 
     @Override
-    protected Double parseSourceValue(Object value) {
+    protected Double parseSourceValue(Object value, String format) {
+        if (format != null) {
+            throw new IllegalArgumentException("Field [" + name() + "] of type [" + typeName() + "] doesn't support formats.");
+        }
+
         double doubleValue = objectToDouble(value);
         double scalingFactor = fieldType().getScalingFactor();
         return Math.round(doubleValue * scalingFactor) / scalingFactor;

modules/mapper-extras/src/main/java/org/elasticsearch/index/mapper/SearchAsYouTypeFieldMapper.java

@@ -419,7 +419,7 @@ protected void parseCreateField(ParseContext context) {
         }
 
         @Override
-        protected Object parseSourceValue(Object value) {
+        protected Object parseSourceValue(Object value, String format) {
             throw new UnsupportedOperationException();
         }
 
@@ -465,7 +465,7 @@ protected void mergeOptions(FieldMapper other, List<String> conflicts) {
         }
 
         @Override
-        protected Object parseSourceValue(Object value) {
+        protected Object parseSourceValue(Object value, String format) {
             throw new UnsupportedOperationException();
         }
 
@@ -588,7 +588,10 @@ protected void parseCreateField(ParseContext context) throws IOException {
     }
 
     @Override
-    protected String parseSourceValue(Object value) {
+    protected String parseSourceValue(Object value, String format) {
+        if (format != null) {
+            throw new IllegalArgumentException("Field [" + name() + "] of type [" + typeName() + "] doesn't support formats.");
+        }
         return value.toString();
     }
 

modules/mapper-extras/src/main/java/org/elasticsearch/index/mapper/TokenCountFieldMapper.java

@@ -159,7 +159,11 @@ protected void parseCreateField(ParseContext context) throws IOException {
     }
 
     @Override
-    protected String parseSourceValue(Object value) {
+    protected String parseSourceValue(Object value, String format) {
+        if (format != null) {
+            throw new IllegalArgumentException("Field [" + name() + "] of type [" + typeName() + "] doesn't support formats.");
+        }
+
         return value.toString();
     }
 

modules/mapper-extras/src/test/java/org/elasticsearch/index/mapper/RankFeatureFieldMapperTests.java

@@ -194,7 +194,7 @@ public void testParseSourceValue() {
         Mapper.BuilderContext context = new Mapper.BuilderContext(settings, new ContentPath());
         RankFeatureFieldMapper mapper = new RankFeatureFieldMapper.Builder("field").build(context);
 
-        assertEquals(3.14f, mapper.parseSourceValue(3.14), 0.0001);
-        assertEquals(42.9f, mapper.parseSourceValue("42.9"), 0.0001);
+        assertEquals(3.14f, mapper.parseSourceValue(3.14, null), 0.0001);
+        assertEquals(42.9f, mapper.parseSourceValue("42.9", null), 0.0001);
     }
 }

modules/mapper-extras/src/test/java/org/elasticsearch/index/mapper/ScaledFloatFieldMapperTests.java

@@ -409,7 +409,7 @@ public void testParseSourceValue() {
             .scalingFactor(100)
             .build(context);
 
-        assertEquals(3.14, mapper.parseSourceValue(3.1415926), 0.00001);
-        assertEquals(3.14, mapper.parseSourceValue("3.1415"), 0.00001);
+        assertEquals(3.14, mapper.parseSourceValue(3.1415926, null), 0.00001);
+        assertEquals(3.14, mapper.parseSourceValue("3.1415", null), 0.00001);
     }
 }

modules/parent-join/src/main/java/org/elasticsearch/join/mapper/MetaJoinFieldMapper.java

@@ -136,7 +136,7 @@ protected void parseCreateField(ParseContext context) throws IOException {
     }
 
     @Override
-    protected Object parseSourceValue(Object value) {
+    protected Object parseSourceValue(Object value, String format) {
         throw new UnsupportedOperationException("The " + typeName() + " field is not stored in _source.");
     }
 

modules/parent-join/src/main/java/org/elasticsearch/join/mapper/ParentIdFieldMapper.java

@@ -186,7 +186,7 @@ protected void parseCreateField(ParseContext context) throws IOException {
     }
 
     @Override
-    protected Object parseSourceValue(Object value) {
+    protected Object parseSourceValue(Object value, String format) {
         throw new UnsupportedOperationException("The " + typeName() + " field is not stored in _source.");
     }
 

modules/parent-join/src/main/java/org/elasticsearch/join/mapper/ParentJoinFieldMapper.java

@@ -348,7 +348,10 @@ protected void parseCreateField(ParseContext context) throws IOException {
     }
 
     @Override
-    protected Object parseSourceValue(Object value) {
+    protected Object parseSourceValue(Object value, String format) {
+        if (format != null) {
+            throw new IllegalArgumentException("Field [" + name() + "] of type [" + typeName() + "] doesn't support formats.");
+        }
         return value;
     }