From 97b4db8438599500a8a02c8d7b4b05add0471627 Mon Sep 17 00:00:00 2001
From: Sven Rebhan <36194019+srebhan@users.noreply.github.com>
Date: Thu, 15 Sep 2022 23:42:18 +0200
Subject: [PATCH] fix(parsers.xpath): Add array index when expanding names.
 (#11781)

---
 plugins/parsers/xpath/json_document.go        | 21 +++++++-
 .../testcases/name_expansion/expected.out     |  3 ++
 .../testcases/name_expansion/telegraf.conf    | 10 ++++
 .../xpath/testcases/name_expansion/test.json  | 48 +++++++++++++++++++
 4 files changed, 81 insertions(+), 1 deletion(-)
 create mode 100644 plugins/parsers/xpath/testcases/name_expansion/expected.out
 create mode 100644 plugins/parsers/xpath/testcases/name_expansion/telegraf.conf
 create mode 100644 plugins/parsers/xpath/testcases/name_expansion/test.json

diff --git a/plugins/parsers/xpath/json_document.go b/plugins/parsers/xpath/json_document.go
index 155ed6335..801f1c35e 100644
--- a/plugins/parsers/xpath/json_document.go
+++ b/plugins/parsers/xpath/json_document.go
@@ -1,6 +1,8 @@
 package xpath
 
 import (
+	"reflect"
+	"strconv"
 	"strings"
 
 	"github.com/antchfx/jsonquery"
@@ -42,7 +44,14 @@ func (d *jsonDocument) GetNodePath(node, relativeTo dataNode, sep string) string
 	// Climb up the tree and collect the node names
 	n := nativeNode.Parent
 	for n != nil && n != nativeRelativeTo {
-		names = append(names, n.Data)
+		switch reflect.TypeOf(n.Parent.Value()).Kind() {
+		case reflect.Slice, reflect.Array:
+			// Determine the index for array elements
+			names = append(names, d.index(n))
+		default:
+			// Use the name if not an array
+			names = append(names, n.Data)
+		}
 		n = n.Parent
 	}
 
@@ -63,3 +72,13 @@ func (d *jsonDocument) OutputXML(node dataNode) string {
 	native := node.(*jsonquery.Node)
 	return native.OutputXML()
 }
+
+func (d *jsonDocument) index(node *jsonquery.Node) string {
+	idx := 0
+
+	for n := node; n.PrevSibling != nil; n = n.PrevSibling {
+		idx++
+	}
+
+	return strconv.Itoa(idx)
+}
diff --git a/plugins/parsers/xpath/testcases/name_expansion/expected.out b/plugins/parsers/xpath/testcases/name_expansion/expected.out
new file mode 100644
index 000000000..f49896f04
--- /dev/null
+++ b/plugins/parsers/xpath/testcases/name_expansion/expected.out
@@ -0,0 +1,3 @@
+devices ok=true,phases_0_load=34,phases_0_voltage=231,phases_1_load=35,phases_1_voltage=231,phases_2_load=36,phases_2_voltage=231,rpm=423,type="Motor" 1662730607000000000
+devices flow=3.1414,hours=8762,ok=true,type="Pump" 1662730607000000000
+devices ok=true,phases_0_load=341,phases_0_voltage=231,phases_1_load=352,phases_1_voltage=231,phases_2_load=363,phases_2_voltage=231,throughput=1026,type="Machine" 1662730607000000000
diff --git a/plugins/parsers/xpath/testcases/name_expansion/telegraf.conf b/plugins/parsers/xpath/testcases/name_expansion/telegraf.conf
new file mode 100644
index 000000000..060720a34
--- /dev/null
+++ b/plugins/parsers/xpath/testcases/name_expansion/telegraf.conf
@@ -0,0 +1,10 @@
+[[inputs.file]]
+  files = ["./testcases/name_expansion/test.json"]
+  data_format = "xpath_json"
+  xpath_native_types = true
+
+  [[inputs.file.xpath]]
+    metric_name = "'devices'"
+    metric_selection = "/devices/*"
+    field_selection = "descendant::*"
+    field_name_expansion = true
diff --git a/plugins/parsers/xpath/testcases/name_expansion/test.json b/plugins/parsers/xpath/testcases/name_expansion/test.json
new file mode 100644
index 000000000..fd08a47d1
--- /dev/null
+++ b/plugins/parsers/xpath/testcases/name_expansion/test.json
@@ -0,0 +1,48 @@
+{
+  "devices": [
+    {
+      "type": "Motor",
+      "rpm": 423,
+      "phases": [
+        {
+          "load": 34,
+          "voltage": 231
+        },
+        {
+          "load": 35,
+          "voltage": 231
+        },
+        {
+          "load": 36,
+          "voltage": 231
+        }
+      ],
+      "ok": true
+    },
+    {
+      "type": "Pump",
+      "hours": 8762,
+      "flow": 3.1414,
+      "ok": true
+    },
+    {
+      "type": "Machine",
+      "throughput": 1026,
+      "phases": [
+        {
+          "load": 341,
+          "voltage": 231
+        },
+        {
+          "load": 352,
+          "voltage": 231
+        },
+        {
+          "load": 363,
+          "voltage": 231
+        }
+      ],
+      "ok": true
+    }
+  ]
+}
\ No newline at end of file