[ENHANCEMENT] StatChart: improve Grafana migration

statchart/schemas/migrate/migrate.cue

@@ -14,9 +14,10 @@
 package migrate
 
 import (
+	"list"
+	"strings"
 	commonMigrate "github.com/perses/perses/cue/common/migrate"
 )
-import "list"
 
 #grafanaType: "stat"
 #panel:       _
@@ -34,10 +35,21 @@ import "list"
 kind: "StatChart"
 spec: {
 	calculation: *commonMigrate.#mapping.calc[#panel.options.reduceOptions.calcs[0]] | commonMigrate.#defaultCalc // only consider [0] here as Perses's GaugeChart doesn't support individual calcs
-    #metricLabel: *#panel.options.reduceOptions.fields | null
-	if #metricLabel != null {
-		metricLabel: #metricLabel
+
+	// metricLabel
+	#textMode: *#panel.options.textMode | null
+    if #textMode == "name" && (*#panel.targets[0].legendFormat | null) != null {
+		// /!\ best effort logic
+		// - if legendFormat contains a more complex expression than {{label}}, the result will be broken (but manually fixable afterwards still)
+		// - Perses's metricLabel is a single setting at panel level, hence the [0], so the result wont fit in case of multiple queries using different legendFormat
+        metricLabel: strings.Trim(#panel.targets[0].legendFormat, "{}")
+    }
+	// /!\ here too using [0] thus not perfect, even though the field getting remapped is unique to the whole panel in that case
+	if #textMode == "auto" && (*#panel.targets[0].format | null) == "table" && (*#panel.options.reduceOptions.fields | null) != null {
+		metricLabel: strings.Trim(#panel.options.reduceOptions.fields, "/^$")
 	}
+
+	// format
 	#unit: *commonMigrate.#mapping.unit[#panel.fieldConfig.defaults.unit] | null
 	if #unit != null {
 		format: unit: #unit
@@ -52,11 +64,13 @@ spec: {
 		}
 	}
 
+	// valueFontSize
 	#fontsize: *#panel.options.text.valueSize | null
-		if #fontsize != null {
-			valueFontSize: #fontsize
-		}
+	if #fontsize != null {
+		valueFontSize: #fontsize
+	}
 
+	// thresholds
 	#steps: *#panel.fieldConfig.defaults.thresholds.steps | null
 	if #steps != null {
 		thresholds: {
@@ -71,79 +85,107 @@ spec: {
 		}
 	}
 
+	// sparkline
 	#sparkline: *#panel.options.graphMode | "none"
 	if #sparkline == "area" {
 		sparkline: {}
 	}
 
-	// Using flatten to avoid having an array of arrays with "value" mappings
-	// (https://cuelang.org/docs/howto/use-list-flattenn-to-flatten-lists/)
-	let x = list.FlattenN([
-		if (*#panel.fieldConfig.defaults.mappings | null) != null for mapping in #panel.fieldConfig.defaults.mappings {
-			if mapping.type == "value" {
-				[for key, option in mapping.options {
-					{
-						kind: "Value"
-						spec: {
-							value: key
-							result: {
-								if option.text != _|_ {
-									value: option.text
-								}
-								if option.color != _|_ {
-									color: *commonMigrate.#mapping.color[option.color] | option.color
+	// mappings
+	#mappings: list.Concat([
+		// Using flatten to get rid of the nested array for "value" mappings
+		// (https://cuelang.org/docs/howto/use-list-flattenn-to-flatten-lists/)
+		list.FlattenN([
+			for mapping in (*#panel.fieldConfig.defaults.mappings | []) {
+				if mapping.type == "value" {
+					[for key, option in mapping.options {
+						{
+							kind: "Value"
+							spec: {
+								value: key
+								result: {
+									if option.text != _|_ {
+										value: option.text
+									}
+									if option.color != _|_ {
+										color: *commonMigrate.#mapping.color[option.color] | option.color
+									}
 								}
 							}
 						}
-					}
-
-				}]
-			}
 
-			if mapping.type == "range" || mapping.type == "regex" || mapping.type == "special" {
-				#result: {
-					value: *mapping.options.result.text | ""
-					if mapping.options.result.color != _|_ {
-						color: *commonMigrate.#mapping.color[mapping.options.result.color] | mapping.options.result.color
-					}
+					}]
 				}
-				[//switch
-					if mapping.type == "range" {
-						kind: "Range"
-						spec: {
-							if mapping.options.from != _|_ {
-								from: mapping.options.from
+				if mapping.type != "value" { // else
+					#result: {
+						value: *mapping.options.result.text | ""
+						if mapping.options.result.color != _|_ {
+							color: *commonMigrate.#mapping.color[mapping.options.result.color] | mapping.options.result.color
+						}
+					}
+					[//switch
+						if mapping.type == "range" {
+							kind: "Range"
+							spec: {
+								if mapping.options.from != _|_ {
+									from: mapping.options.from
+								}
+								if mapping.options.to != _|_ {
+									to: mapping.options.to
+								}
+								result: #result
 							}
-							if mapping.options.to != _|_ {
-								to: mapping.options.to
+						},
+						if mapping.type == "regex" {
+							kind: "Regex"
+							spec: {
+								pattern: mapping.options.pattern
+								result:  #result
 							}
-							result: #result
-						}
-					},
-					if mapping.type == "regex" {
-						kind: "Regex"
-						spec: {
-							pattern: mapping.options.pattern
-							result:  #result
-						}
-					},
-					if mapping.type == "special" {
-						kind: "Misc"
+						},
+						if mapping.type == "special" {
+							kind: "Misc"
+							spec: {
+								value: [//switch
+									if mapping.options.match == "nan" {"NaN"},
+									if mapping.options.match == "null+nan" {"null"},
+									mapping.options.match,
+								][0]
+								result: #result
+							}
+						},
+					][0]
+				}
+			}
+		], 1),
+		for override in (*#panel.fieldConfig.overrides | [])
+		if override.matcher.id == "byName" && override.matcher.options == "Value"
+		for property in override.properties
+		if property.id == "mappings" {
+			list.FlattenN([
+				for v in property.value {
+					if v.type == "value" {
+						[for oK, oV in v.options {
+							kind: "Value"
+							spec: {
+								result: value: oV.text
+								value: oK
+							}
+						}]
+					}
+					if v.type == "range" {
+						kind: "Range"
 						spec: {
-							value: [//switch
-								if mapping.options.match == "nan" {"NaN"},
-								if mapping.options.match == "null+nan" {"null"},
-								mapping.options.match,
-							][0]
-							result: #result
+							result: value: v.options.result.text
+							from: v.options.from
+							to: v.options.to
 						}
-					},
-				][0]
-			}
-		},
-	], 1)
-
-	if len(x) > 0 {
-		mappings: x
+					}
+				}
+			], 1),
+		}
+	])
+	if len(#mappings) > 0 {
+		mappings: #mappings
 	}
 }

statchart/schemas/migrate/tests/basic/expected.json

@@ -6,7 +6,6 @@
       "decimalPlaces": 2,
       "unit": "bytes/sec"
     },
-    "metricLabel": "",
     "sparkline": {},
     "thresholds": {
       "steps": [

statchart/schemas/migrate/tests/label-display-from-legend/expected.json

@@ -0,0 +1,10 @@
+{
+  "kind": "StatChart",
+  "spec": {
+    "metricLabel": "version",
+    "format": {
+      "unit": "decimal"
+    },
+    "calculation": "mean"
+  }
+}

statchart/schemas/migrate/tests/label-display-from-legend/input.json

@@ -0,0 +1,61 @@
+{
+  "id": 9,
+  "type": "stat",
+  "title": "Exporter version [$application - $environment - $nodename]",
+  "description": " - {{version}}: Node Exporter version used",
+  "gridPos": {
+    "x": 6,
+    "y": 5,
+    "h": 3,
+    "w": 3
+  },
+  "fieldConfig": {
+    "defaults": {
+      "mappings": [],
+      "color": {
+        "mode": "thresholds"
+      },
+      "links": [],
+      "unit": "none"
+    },
+    "overrides": []
+  },
+  "pluginVersion": "11.6.3",
+  "targets": [
+    {
+      "exemplar": false,
+      "expr": "node_exporter_build_info{osname=~\".*Linux.*\", application=~\"$application\", environment=~\"$environment\", nodename=~\"$nodename\", instance=~\".*:50700\"}",
+      "format": "time_series",
+      "hide": false,
+      "instant": true,
+      "interval": "$sampling",
+      "intervalFactor": 1,
+      "legendFormat": "{{version}}",
+      "refId": "version_linux",
+      "datasource": {
+        "uid": "$datasource"
+      },
+      "editorMode": "code"
+    }
+  ],
+  "datasource": {
+    "uid": "$datasource"
+  },
+  "options": {
+    "reduceOptions": {
+      "values": false,
+      "calcs": [
+        "mean"
+      ],
+      "fields": ""
+    },
+    "orientation": "auto",
+    "textMode": "name",
+    "wideLayout": true,
+    "colorMode": "background",
+    "graphMode": "none",
+    "justifyMode": "auto",
+    "showPercentChange": false,
+    "percentChangeColorMode": "standard"
+  }
+}

statchart/schemas/migrate/tests/label-display-from-options/expected.json

@@ -0,0 +1,10 @@
+{
+  "kind": "StatChart",
+  "spec": {
+    "metricLabel": "version",
+    "format": {
+      "unit": "decimal"
+    },
+    "calculation": "last-number"
+  }
+}

statchart/schemas/migrate/tests/label-display-from-options/input.json

@@ -0,0 +1,61 @@
+{
+  "id": 9,
+  "type": "stat",
+  "title": "Exporter version [$application - $environment - $nodename]",
+  "description": " - {{version}}: Node Exporter version used",
+  "gridPos": {
+    "x": 6,
+    "y": 5,
+    "h": 3,
+    "w": 3
+  },
+  "fieldConfig": {
+    "defaults": {
+      "mappings": [],
+      "color": {
+        "mode": "thresholds"
+      },
+      "links": [],
+      "unit": "none"
+    },
+    "overrides": []
+  },
+  "pluginVersion": "11.6.3",
+  "targets": [
+    {
+      "exemplar": false,
+      "expr": "node_exporter_build_info{osname=~\".*Linux.*\", application=~\"$application\", environment=~\"$environment\", nodename=~\"$nodename\", instance=~\".*:50700\"}",
+      "format": "table",
+      "hide": false,
+      "instant": true,
+      "interval": "$sampling",
+      "intervalFactor": 1,
+      "legendFormat": "DO NOT USE ME",
+      "refId": "version_linux",
+      "datasource": {
+        "uid": "$datasource"
+      },
+      "editorMode": "code"
+    }
+  ],
+  "datasource": {
+    "uid": "$datasource"
+  },
+  "options": {
+    "reduceOptions": {
+      "values": false,
+      "calcs": [
+        "lastNotNull"
+      ],
+      "fields": "/^version$/"
+    },
+    "orientation": "auto",
+    "textMode": "auto",
+    "wideLayout": true,
+    "colorMode": "background",
+    "graphMode": "none",
+    "justifyMode": "auto",
+    "showPercentChange": false,
+    "percentChangeColorMode": "standard"
+  }
+}

statchart/schemas/migrate/tests/mappings/input.json

@@ -1,6 +1,6 @@
 {
   "datasource": "$datasource",
-  "description": "Just displaying some metrics with Stat panel",
+  "description": "Test the migration of Grafana mappings to Perses mappings",
   "fieldConfig": {
     "defaults": {
       "mappings": [