Support Grafana 'timeseries' panel type for analyse grafana.

This adds a workaround to parse the 'targets' out of a panel with type
'timeseries', not currently supported upstream. It also improves the
error handling when an unknown panel type is encountered.

When the functionality is merged upstream, this change can be removed.

CHANGELOG.md

@@ -5,6 +5,7 @@ Order should be `CHANGE`, `FEATURE`, `ENHANCEMENT`, and `BUGFIX`
 ## unreleased
 
 * [ENHANCEMENT] Benchtool: add `-bench.write.proxy-url` argument for configuring the Prometheus remote-write client with a HTTP proxy URL. #223
+* [ENHANCEMENT] Analyse: support Grafana 'timeseries' panel type for `cortextool analyse grafana` command. #224
 
 ## v0.10.6
 

pkg/analyse/grafana.go

@@ -1,6 +1,7 @@
 package analyse
 
 import (
+	"encoding/json"
 	"fmt"
 	"regexp"
 	"sort"
@@ -114,14 +115,55 @@ func metricsFromTemplating(templating sdk.Templating, metrics map[string]struct{
 	return parseErrors
 }
 
+// Workaround to support Grafana "timeseries" panel. This should
+// be implemented in grafana/tools-sdk, and removed from here.
+func getCustomPanelTargets(panel sdk.Panel) *[]sdk.Target {
+	if panel.CommonPanel.Type != "timeseries" {
+		return nil
+	}
+
+	// Heavy handed approach to re-marshal the panel and parse it again
+	// so that we can extract the 'targets' field in the right format.
+
+	bytes, err := json.Marshal(panel.CustomPanel)
+	if err != nil {
+		log.Debugln("msg", "panel re-marshalling error", "err", err)
+		return nil
+	}
+
+	type panelType struct {
+		Targets []sdk.Target `json:"targets,omitempty"`
+	}
+
+	var parsedPanel panelType
+	err = json.Unmarshal(bytes, &parsedPanel)
+	if err != nil {
+		log.Debugln("msg", "panel parsing error", "err", err)
+		return nil
+	}
+
+	return &parsedPanel.Targets
+}
+
+func getPanelTargets(panel sdk.Panel) *[]sdk.Target {
+	targets := panel.GetTargets()
+	if targets == nil {
+		targets = getCustomPanelTargets(panel)
+	}
+
+	return targets
+}
+
 func metricsFromPanel(panel sdk.Panel, metrics map[string]struct{}) []error {
 	var parseErrors []error
 
-	if panel.GetTargets() == nil {
+	targets := getPanelTargets(panel)
+	if targets == nil {
+		parseErrors = append(parseErrors, fmt.Errorf("unsupported panel type: %q", panel.CommonPanel.Type))
 		return parseErrors
 	}
 
-	for _, target := range *panel.GetTargets() {
+	for _, target := range *targets {
 		// Prometheus has this set.
 		if target.Expr == "" {
 			continue

pkg/commands/analyse_grafana_test.go

@@ -38,3 +38,22 @@ func TestParseMetricsInBoard(t *testing.T) {
 	analyse.ParseMetricsInBoard(output, board)
 	assert.Equal(t, dashboardMetrics, output.Dashboards[0].Metrics)
 }
+
+var timeseriesPanelMetrics = []string{
+	"my_lovely_metric",
+}
+
+func TestParseMetricsInBoardWithTimeseriesPanel(t *testing.T) {
+	var board sdk.Board
+	output := &analyse.MetricsInGrafana{}
+	output.OverallMetrics = make(map[string]struct{})
+
+	buf, err := loadFile("testdata/timeseries.json")
+	require.NoError(t, err)
+
+	err = json.Unmarshal(buf, &board)
+	require.NoError(t, err)
+
+	analyse.ParseMetricsInBoard(output, board)
+	assert.Equal(t, timeseriesPanelMetrics, output.Dashboards[0].Metrics)
+}

pkg/commands/testdata/timeseries.json

@@ -0,0 +1,147 @@
+{
+  "__inputs": [ ],
+  "__requires": [
+    {
+      "type": "grafana",
+      "id": "grafana",
+      "name": "Grafana",
+      "version": "8.2.3-40566"
+    },
+    {
+      "type": "datasource",
+      "id": "prometheus",
+      "name": "Prometheus",
+      "version": "1.0.0"
+    },
+    {
+      "type": "panel",
+      "id": "timeseries",
+      "name": "Time series",
+      "version": ""
+    }
+  ],
+  "annotations": {
+    "list": [
+      {
+        "builtIn": 1,
+        "datasource": "-- Grafana --",
+        "enable": true,
+        "hide": true,
+        "iconColor": "rgba(0, 211, 255, 1)",
+        "name": "Annotations & Alerts",
+        "target": {
+          "limit": 100,
+          "matchAny": false,
+          "tags": [],
+          "type": "dashboard"
+        },
+        "type": "dashboard"
+      }
+    ]
+  },
+  "editable": true,
+  "fiscalYearStartMonth": 0,
+  "gnetId": null,
+  "graphTooltip": 0,
+  "id": null,
+  "links": [],
+  "liveNow": false,
+  "panels": [
+    {
+      "datasource": "$datasource",
+      "fieldConfig": {
+        "defaults": {
+          "color": {
+            "mode": "palette-classic"
+          },
+          "custom": {
+            "axisLabel": "",
+            "axisPlacement": "auto",
+            "barAlignment": 0,
+            "drawStyle": "line",
+            "fillOpacity": 0,
+            "gradientMode": "none",
+            "hideFrom": {
+              "legend": false,
+              "tooltip": false,
+              "viz": false
+            },
+            "lineInterpolation": "linear",
+            "lineWidth": 1,
+            "pointSize": 5,
+            "scaleDistribution": {
+              "type": "linear"
+            },
+            "showPoints": "auto",
+            "spanNulls": false,
+            "stacking": {
+              "group": "A",
+              "mode": "none"
+            },
+            "thresholdsStyle": {
+              "mode": "off"
+            }
+          },
+          "mappings": [],
+          "thresholds": {
+            "mode": "absolute",
+            "steps": [
+              {
+                "color": "green",
+                "value": null
+              },
+              {
+                "color": "red",
+                "value": 80
+              }
+            ]
+          }
+        },
+        "overrides": []
+      },
+      "gridPos": {
+        "h": 9,
+        "w": 12,
+        "x": 0,
+        "y": 0
+      },
+      "id": 2,
+      "options": {
+        "legend": {
+          "calcs": [],
+          "displayMode": "list",
+          "placement": "bottom"
+        },
+        "tooltip": {
+          "mode": "single"
+        }
+      },
+      "targets": [
+        {
+          "exemplar": true,
+          "expr": "1+2+3+count(my_lovely_metric)",
+          "interval": "",
+          "legendFormat": "",
+          "refId": "A"
+        }
+      ],
+      "title": "Panel Title",
+      "type": "timeseries"
+    }
+  ],
+  "schemaVersion": 32,
+  "style": "dark",
+  "tags": [],
+  "templating": {
+    "list": []
+  },
+  "time": {
+    "from": "now-6h",
+    "to": "now"
+  },
+  "timepicker": {},
+  "timezone": "",
+  "title": "Dashboard with timeseries panel",
+  "uid": "TX7rYEc7k",
+  "version": 2
+}