x-pack/filebeat/input/httpjson: fix handling of array of string/array

Co-authored-by: Alex Resnick <adr8292@gmail.com>

CHANGELOG.next.asciidoc

@@ -56,6 +56,7 @@ https://github.com/elastic/beats/compare/v8.2.0\...main[Check the HEAD diff]
 - Fix gc.log always shipped even if gc fileset is disabled {issue}30995[30995]
 - Fix handling of empty array in httpjson input. {pull}32001[32001]
 - Fix reporting of `filebeat.events.active` in log events such that the current value is always reported instead of the difference from the last value. {pull}33597[33597]
+- Fix splitting array of strings/arrays in httpjson input {issue}30345[30345] {pull}33609[33609]
 
 *Heartbeat*
 - Fix bug affecting let's encrypt and other users of cross-signed certs, where cert expiration was incorrectly calculated. {issue}33215[33215]

x-pack/filebeat/input/httpjson/split.go

@@ -144,14 +144,15 @@ func (s *split) split(ctx *transformContext, root mapstr.M, ch chan<- maybeMsg)
 		}
 
 		for _, e := range varr {
-			if err := s.sendMessage(ctx, root, "", e, ch); err != nil {
+			err := s.sendMessage(ctx, root, s.targetInfo.Name, e, ch)
+			if err != nil {
 				s.log.Debug(err)
 			}
 		}
 
 		return nil
 	case splitTypeMap:
-		vmap, ok := toMapStr(v)
+		vmap, ok := toMapStr(v, s.targetInfo.Name)
 		if !ok {
 			return errExpectedSplitObj
 		}
@@ -211,19 +212,17 @@ func (s *split) split(ctx *transformContext, root mapstr.M, ch chan<- maybeMsg)
 // sendMessage sends an array or map split result value, v, on ch after performing
 // any necessary transformations. If key is "", the value is an element of an array.
 func (s *split) sendMessage(ctx *transformContext, root mapstr.M, key string, v interface{}, ch chan<- maybeMsg) error {
-	obj, ok := toMapStr(v)
+	obj, ok := toMapStr(v, s.targetInfo.Name)
 	if !ok {
 		return errExpectedSplitObj
 	}
-
-	clone := root.Clone()
-
 	if s.keyField != "" && key != "" {
 		_, _ = obj.Put(s.keyField, key)
 	}
 
+	clone := root.Clone()
 	if s.keepParent {
-		_, _ = clone.Put(s.targetInfo.Name, obj)
+		_, _ = clone.Put(s.targetInfo.Name, v)
 	} else {
 		clone = obj
 	}
@@ -248,7 +247,7 @@ func (s *split) sendMessage(ctx *transformContext, root mapstr.M, key string, v
 	return nil
 }
 
-func toMapStr(v interface{}) (mapstr.M, bool) {
+func toMapStr(v interface{}, key string) (mapstr.M, bool) {
 	if v == nil {
 		return mapstr.M{}, false
 	}
@@ -257,6 +256,8 @@ func toMapStr(v interface{}) (mapstr.M, bool) {
 		return t, true
 	case map[string]interface{}:
 		return mapstr.M(t), true
+	case string, []bool, []int, []string, []interface{}:
+		return mapstr.M{key: t}, true
 	}
 	return mapstr.M{}, false
 }

x-pack/filebeat/input/httpjson/split_test.go

@@ -624,6 +624,83 @@ func TestSplit(t *testing.T) {
 				{"@timestamp": "1234567890", "other_items": "Line 3"},
 			},
 		},
+		{
+			name: "Array of Strings with keep_parent",
+			config: &splitConfig{
+				Target:     "body.alerts",
+				Type:       "array",
+				KeepParent: true,
+			},
+			ctx: emptyTransformContext(),
+			resp: transformable{
+				"body": mapstr.M{
+					"this": "is kept",
+					"alerts": []interface{}{
+						"test1",
+						"test2",
+						"test3",
+					},
+				},
+			},
+			expectedMessages: []mapstr.M{
+				{
+					"this":   "is kept",
+					"alerts": "test1",
+				},
+				{
+					"this":   "is kept",
+					"alerts": "test2",
+				},
+				{
+					"this":   "is kept",
+					"alerts": "test3",
+				},
+			},
+			expectedErr: nil,
+		},
+		{
+			name: "Array of Arrays with keep_parent",
+			config: &splitConfig{
+				Target:     "body.alerts",
+				Type:       "array",
+				KeepParent: true,
+			},
+			ctx: emptyTransformContext(),
+			resp: transformable{
+				"body": mapstr.M{
+					"this": "is kept",
+					"alerts": []interface{}{
+						[]interface{}{"test1-1", "test1-2"},
+						[]string{"test2-1", "test2-2"},
+						[]int{1, 2},
+					},
+				},
+			},
+			expectedMessages: []mapstr.M{
+				{
+					"this": "is kept",
+					"alerts": []interface{}{
+						"test1-1",
+						"test1-2",
+					},
+				},
+				{
+					"this": "is kept",
+					"alerts": []string{
+						"test2-1",
+						"test2-2",
+					},
+				},
+				{
+					"this": "is kept",
+					"alerts": []int{
+						1,
+						2,
+					},
+				},
+			},
+			expectedErr: nil,
+		},
 	}
 
 	for _, tc := range cases {