Add read only replica (#11)

* Improve stats gathering.

monitoring/helpers.go

@@ -3,57 +3,78 @@ package libpack_monitoring
 import (
 	"fmt"
 	"os"
-	"sort"
 	"strings"
+	"unicode"
 
 	libpack_config "github.com/lukaszraczylo/graphql-monitoring-proxy/config"
 )
 
 func (ms *MetricsSetup) get_metrics_name(name string, labels map[string]string) (complete_name string) {
-	var err error
 	if labels == nil {
 		labels = make(map[string]string)
 	}
+
+	// Adding default labels
 	labels["microservice"] = libpack_config.PKG_NAME
-	labels["pod"], err = os.Hostname()
+	if podName, err := os.Hostname(); err == nil {
-	if err != nil {
+		labels["pod"] = podName
+	} else {
 		labels["pod"] = "unknown"
 	}
 
+	var sb strings.Builder
 	if ms.metrics_prefix != "" {
-		complete_name = ms.metrics_prefix + "_" + name
+		sb.WriteString(ms.metrics_prefix)
-	} else {
+		sb.WriteString("_")
-		complete_name = name
 	}
-	if labels != nil {
+	sb.WriteString(name)
-		keys := make([]string, 0, len(labels))
+
-		for k := range labels {
+	if len(labels) > 0 {
-			keys = append(keys, k)
+		sb.WriteString("{")
+		first := true
+		for k, v := range labels {
+			if !first {
+				sb.WriteString(",")
+			}
+			sb.WriteString(k)
+			sb.WriteString("=\"")
+			sb.WriteString(v)
+			sb.WriteString("\"")
+			first = false
 		}
-		sort.Strings(keys)
+		sb.WriteString("}")
-		complete_name += "{"
-		for _, k := range keys {
-			complete_name += k + "=\"" + labels[k] + "\","
-		}
-		complete_name = strings.TrimSuffix(complete_name, ",")
-		complete_name += "}"
 	}
-	return
+
+	return sb.String()
 }
 
 // validate_metrics_name validates the name of the metric to adhere to the Prometheus naming conventions
 // https://prometheus.io/docs/practices/naming/
 func validate_metrics_name(name string) error {
-	// replace all spaces with underscores and remove all other non-alphanumeric characters
+	var sb strings.Builder // Use strings.Builder for efficient string concatenation
-	name_new := strings.ReplaceAll(name, " ", "_")
+
-	name_new = strings.Map(func(r rune) rune {
+	// Track if the last character was an underscore to avoid duplicate underscores
-		if (r >= 'a' && r <= 'z') || (r >= 'A' && r <= 'Z') || (r >= '0' && r <= '9') || r == '_' {
+	lastWasUnderscore := false
-			return r
+
+	for _, r := range name {
+		// Convert spaces to underscores and skip non-alphanumeric characters except underscores
+		if r == ' ' || (unicode.IsLetter(r) || unicode.IsDigit(r) || r == '_') {
+			if r == ' ' || r == '_' {
+				if lastWasUnderscore {
+					continue // Skip if the previous character was also an underscore
+				}
+				r = '_' // Convert spaces to underscores
+				lastWasUnderscore = true
+			} else {
+				lastWasUnderscore = false
+			}
+			sb.WriteRune(r) // Add valid characters to the builder
 		}
-		return -1
+	}
-	}, name_new)
+	// Trim leading and trailing underscores
-	name_new = strings.ReplaceAll(name_new, "__", "_")
+	name_new := strings.Trim(sb.String(), "_")
-	name_new = strings.Trim(name_new, "_")
+
+	// Check if the processed name matches the original input
 	if name_new != name {
 		return fmt.Errorf("Invalid metric name: %s, expected %s", name, name_new)
 	}