extract metric usage from panel in grafana collector

Signed-off-by: Augustin Husson <[email protected]>

source/grafana/grafana.go

@@ -3,6 +3,8 @@ package grafana
 import (
 	"context"
 	"encoding/json"
+	"fmt"
+	"strings"
 
 	"github.com/go-openapi/strfmt"
 	grafanaapi "github.com/grafana/grafana-openapi-client-go/client"
@@ -12,9 +14,22 @@ import (
 	"github.com/perses/metrics-usage/config"
 	"github.com/perses/metrics-usage/database"
 	modelAPIV1 "github.com/perses/metrics-usage/pkg/api/v1"
+	"github.com/perses/metrics-usage/utils"
+	"github.com/perses/metrics-usage/utils/prometheus"
 	"github.com/sirupsen/logrus"
 )
 
+var variableReplacer = strings.NewReplacer(
+	"$__interval", "5m",
+	"$interval", "5m",
+	"$resolution", "5m",
+	"$__rate_interval", "15s",
+	"$rate_interval", "15s",
+	"$__range", "1d",
+	"${__range_s:glob}", "15",
+	"${__range_s}", "15",
+)
+
 func NewCollector(db database.Database, cfg config.GrafanaCollector) (async.SimpleTask, error) {
 	httpClient, err := config.NewHTTPClient(cfg.HTTPClient)
 	url := cfg.HTTPClient.URL.URL
@@ -63,6 +78,29 @@ func (c *grafanaCollector) Execute(ctx context.Context, _ context.CancelFunc) er
 	return nil
 }
 
+func (c *grafanaCollector) extractMetricUsage(metricUsage map[string]*modelAPIV1.MetricUsage, dashboard *simplifiedDashboard) {
+	c.extractMetricUsageFromPanels(metricUsage, dashboard.Panels, dashboard)
+	for _, r := range dashboard.Rows {
+		c.extractMetricUsageFromPanels(metricUsage, r.Panels, dashboard)
+		// TODO extract metric usage from variable
+	}
+}
+
+func (c *grafanaCollector) extractMetricUsageFromPanels(metricUsage map[string]*modelAPIV1.MetricUsage, panels []panel, dashboard *simplifiedDashboard) {
+	for _, p := range panels {
+		for _, t := range extractTarget(p) {
+			if len(t.Expr) == 0 {
+				continue
+			}
+			metrics, err := prometheus.ExtractMetricNamesFromPromQL(replaceVariables(t.Expr))
+			if err != nil {
+				logrus.WithError(err).Errorf("failed to extract metric names from PromQL expression in the panel %q for the dashboard %s/%s", p.Title, dashboard.Title, dashboard.UID)
+			}
+			c.populateUsage(metricUsage, metrics, dashboard)
+		}
+	}
+}
+
 func (c *grafanaCollector) getDashboard(uid string) (*simplifiedDashboard, error) {
 	response, err := c.client.Dashboards.GetDashboardByUID(uid)
 	if err != nil {
@@ -101,6 +139,23 @@ func (c *grafanaCollector) collectAllDashboardUID(ctx context.Context) ([]*grafa
 	return result, nil
 }
 
+func (c *grafanaCollector) populateUsage(metricUsage map[string]*modelAPIV1.MetricUsage, metricNames []string, currentDashboard *simplifiedDashboard) {
+	dashboardURL := fmt.Sprintf("%s/d/%s", c.grafanaURL, currentDashboard.UID)
+	for _, metricName := range metricNames {
+		if usage, ok := metricUsage[metricName]; ok {
+			usage.Dashboards = utils.InsertIfNotPresent(usage.Dashboards, dashboardURL)
+		} else {
+			metricUsage[metricName] = &modelAPIV1.MetricUsage{
+				Dashboards: []string{dashboardURL},
+			}
+		}
+	}
+}
+
 func (c *grafanaCollector) String() string {
 	return "grafana collector"
 }
+
+func replaceVariables(expr string) string {
+	return variableReplacer.Replace(expr)
+}

source/grafana/model.go

@@ -15,13 +15,6 @@ type row struct {
 	Panels []panel `json:"panels"`
 }
 
-type annotation struct {
-	Name  string `json:"name"`
-	Query string `json:"query"`
-	Expr  string `json:"expr"`
-	Type  string `json:"type"`
-}
-
 type templateVar struct {
 	Name  string      `json:"name"`
 	Type  string      `json:"type"`
@@ -36,7 +29,12 @@ type simplifiedDashboard struct {
 	Templating struct {
 		List []templateVar `json:"list"`
 	} `json:"templating"`
-	Annotations struct {
-		List []annotation `json:"list"`
-	} `json:"annotations"`
+}
+
+func extractTarget(panel panel) []target {
+	var targets []target
+	for _, p := range panel.Panels {
+		targets = append(targets, extractTarget(p)...)
+	}
+	return append(targets, panel.Targets...)
 }

source/perses/perses.go

@@ -40,18 +40,18 @@ func NewCollector(db database.Database, cfg config.PersesCollector) (async.Simpl
 		return nil, err
 	}
 	return &persesCollector{
-		SimpleTask:   nil,
-		client:       persesClientV1.NewWithClient(restClient).Dashboard(""),
-		db:           db,
-		DashboardURL: cfg.HTTPClient.URL.String(),
+		SimpleTask: nil,
+		client:     persesClientV1.NewWithClient(restClient).Dashboard(""),
+		db:         db,
+		persesURL:  cfg.HTTPClient.URL.String(),
 	}, nil
 }
 
 type persesCollector struct {
 	async.SimpleTask
-	client       persesClientV1.DashboardInterface
-	db           database.Database
-	DashboardURL string
+	client    persesClientV1.DashboardInterface
+	db        database.Database
+	persesURL string
 }
 
 func (c *persesCollector) Execute(_ context.Context, _ context.CancelFunc) error {
@@ -128,7 +128,7 @@ func (c *persesCollector) extractMetricUsageFromVariables(metricUsage map[string
 }
 
 func (c *persesCollector) populateUsage(metricUsage map[string]*modelAPIV1.MetricUsage, metricNames []string, currentDashboard *v1.Dashboard) {
-	dashboardURL := fmt.Sprintf("%s/api/v1/projects/%s/dashboards/%s", c.DashboardURL, currentDashboard.Metadata.Project, currentDashboard.Metadata.Name)
+	dashboardURL := fmt.Sprintf("%s/api/v1/projects/%s/dashboards/%s", c.persesURL, currentDashboard.Metadata.Project, currentDashboard.Metadata.Name)
 	for _, metricName := range metricNames {
 		if usage, ok := metricUsage[metricName]; ok {
 			usage.Dashboards = utils.InsertIfNotPresent(usage.Dashboards, dashboardURL)