PMM-14431 Lint, refactor, improvements.

Author: JiriCtvrtka

exporter/collstats_collector_test.go

@@ -33,7 +33,7 @@ import (
 )
 
 func TestCollStatsCollectorAccountIndexes(t *testing.T) {
-	ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
+	ctx, cancel := context.WithTimeout(t.Context(), 3*time.Second)
 	defer cancel()
 
 	client := tu.DefaultTestClient(ctx, t)

exporter/metrics.go

@@ -213,24 +213,24 @@ func allReservedNames(client *mongo.Client) ([]string, error) {
 	reservedNames := []string{}
 	dbs, err := client.ListDatabaseNames(ctx, struct{}{})
 	if err != nil {
-		return reservedNames, err
+		return reservedNames, errors.Wrap(err, "ListDatabaseNames failed")
 	}
 
 	for _, dbName := range dbs {
 		fmt.Printf("Database: %s\n", dbName)
 		db := client.Database(dbName)
 		collCursor, err := db.ListCollections(ctx, struct{}{})
 		if err != nil {
-			return reservedNames, err
+			return reservedNames, errors.Wrapf(err, "ListCollections failed for db %s", dbName)
 		}
-		defer collCursor.Close(ctx)
+		defer collCursor.Close(ctx) //nolint:errcheck
 		for collCursor.Next(ctx) {
 			var collInfo struct {
 				Name string `bson:"name"`
 				Type string `bson:"type"`
 			}
 			if err := collCursor.Decode(&collInfo); err != nil {
-				return reservedNames, err
+				return reservedNames, errors.Wrapf(err, "Decode failed for collection in db %s", dbName)
 			}
 			reservedNames = append(reservedNames, collInfo.Name)
 			if collInfo.Type == "view" {
@@ -241,7 +241,7 @@ func allReservedNames(client *mongo.Client) ([]string, error) {
 			if err != nil {
 				continue // skip if cannot list indexes
 			}
-			defer cursor.Close(ctx)
+			defer cursor.Close(ctx) //nolint:errcheck
 			for cursor.Next(ctx) {
 				var indexDoc map[string]interface{}
 				if err := cursor.Decode(&indexDoc); err != nil {
@@ -380,58 +380,64 @@ func makeMetrics(client *mongo.Client, prefix string, m bson.M, labels map[strin
 		} else {
 			l = labels
 		}
-		switch v := val.(type) {
-		case bson.M:
-			res = append(res, makeMetrics(client, nextPrefix, v, l, compatibleMode)...)
-		case map[string]interface{}:
-			res = append(res, makeMetrics(client, nextPrefix, v, l, compatibleMode)...)
-		case primitive.A:
-			res = append(res, processSlice(client, nextPrefix, v, l, compatibleMode)...)
-		case []interface{}:
-			continue
-		default:
-			reservedNames, err := allReservedNames(client)
-			if err != nil {
-				fmt.Printf("\n\n\n cannot get reserved names: %v \n\n\n", err)
-				continue
-			}
+		res = append(res, handleMetric(client, prefix, nextPrefix, k, val, l, compatibleMode)...)
+	}
+
+	return res
+}
+
+func handleMetric(client *mongo.Client, prefix, nextPrefix, k string, val interface{}, l map[string]string, compatibleMode bool) []prometheus.Metric {
+	var res []prometheus.Metric
+	switch v := val.(type) {
+	case bson.M:
+		res = append(res, makeMetrics(client, nextPrefix, v, l, compatibleMode)...)
+	case map[string]interface{}:
+		res = append(res, makeMetrics(client, nextPrefix, v, l, compatibleMode)...)
+	case primitive.A:
+		res = append(res, processSlice(client, nextPrefix, v, l, compatibleMode)...)
+	case []interface{}:
+		// skip
+	default:
+		reservedNames, err := allReservedNames(client)
+		if err != nil {
+			fmt.Printf("\n\n\n cannot get reserved names: %v \n\n\n", err)
+			return res
+		}
+
+		rm, err := makeRawMetric(reservedNames, prefix, k, v, l)
+		if err != nil {
+			invalidMetric := prometheus.NewInvalidMetric(prometheus.NewInvalidDesc(err), err)
+			res = append(res, invalidMetric)
+			return res
+		}
+
+		// makeRawMetric returns a nil metric for some data types like strings
+		// because we cannot extract data from all types
+		if rm == nil {
+			return res
+		}
 
-			rm, err := makeRawMetric(reservedNames, prefix, k, v, l)
+		metrics := []*rawMetric{rm}
+
+		if renamedMetrics := metricRenameAndLabel(rm, specialConversions); renamedMetrics != nil {
+			metrics = renamedMetrics
+		}
+
+		for _, m := range metrics {
+			metric, err := rawToPrometheusMetric(m)
 			if err != nil {
 				invalidMetric := prometheus.NewInvalidMetric(prometheus.NewInvalidDesc(err), err)
 				res = append(res, invalidMetric)
 				continue
 			}
 
-			// makeRawMetric returns a nil metric for some data types like strings
-			// because we cannot extract data from all types
-			if rm == nil {
-				continue
-			}
-
-			metrics := []*rawMetric{rm}
+			res = append(res, metric)
 
-			if renamedMetrics := metricRenameAndLabel(rm, specialConversions); renamedMetrics != nil {
-				metrics = renamedMetrics
-			}
-
-			for _, m := range metrics {
-				metric, err := rawToPrometheusMetric(m)
-				if err != nil {
-					invalidMetric := prometheus.NewInvalidMetric(prometheus.NewInvalidDesc(err), err)
-					res = append(res, invalidMetric)
-					continue
-				}
-
-				res = append(res, metric)
-
-				if compatibleMode {
-					res = appendCompatibleMetric(res, m)
-				}
+			if compatibleMode {
+				res = appendCompatibleMetric(res, m)
 			}
 		}
 	}
-
 	return res
 }