* first cut at a "dnstapir-cli edm stats" command (#52)

* * first cut at a "dnstapir-cli edm stats" command

* * changed to use an HTTP agent with a timeout to avoid infinite
  hangs if EDM isn't responding

Author: johanix

cmd/edm.go

@@ -0,0 +1,164 @@
+/*
+ * Copyright (c) 2024 Johan Stenstam, johan.stenstam@internetstiftelsen.se
+ */
+
+package cmd
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"log"
+	"net/http"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/ryanuber/columnize"
+	"github.com/spf13/cobra"
+)
+
+var EdmCmd = &cobra.Command{
+	Use:   "edm",
+	Short: "Prefix command for EDM (Edge DNSTAP Minimiser) operations",
+}
+
+var EdmStatsCmd = &cobra.Command{
+	Use:   "stats",
+	Short: "Get statistics from the EDM metrics endpoint",
+	Run: func(cmd *cobra.Command, args []string) {
+		if len(args) != 0 {
+			log.Fatal("stats must have no arguments")
+		}
+
+		// Get the metrics endpoint URL (hardcoded in EDM as 127.0.0.1:2112)
+		metricsURL := "http://127.0.0.1:2112/metrics"
+
+		// Create HTTP client with timeout
+		client := &http.Client{
+			Timeout: time.Second * 4,
+		}
+
+		// Make HTTP GET request
+		resp, err := client.Get(metricsURL)
+		if err != nil {
+			log.Fatalf("Error connecting to EDM metrics endpoint at %s: %v\n"+
+				"Is EDM running?", metricsURL, err)
+		}
+		defer resp.Body.Close()
+
+		if resp.StatusCode != http.StatusOK {
+			log.Fatalf("HTTP error from metrics endpoint: %s", resp.Status)
+		}
+
+		// Parse Prometheus text format
+		metrics, err := parsePrometheusMetrics(resp.Body)
+		if err != nil {
+			log.Fatalf("Error parsing metrics: %v", err)
+		}
+
+		// Display EDM metrics in table format
+		displayEdmMetrics(metrics)
+	},
+}
+
+func init() {
+	EdmCmd.AddCommand(EdmStatsCmd)
+}
+
+// parsePrometheusMetrics parses Prometheus text format and returns a map of metric name to value
+func parsePrometheusMetrics(r io.Reader) (map[string]float64, error) {
+	metrics := make(map[string]float64)
+	scanner := bufio.NewScanner(r)
+
+	for scanner.Scan() {
+		line := strings.TrimSpace(scanner.Text())
+
+		// Skip empty lines and comments
+		if line == "" || strings.HasPrefix(line, "#") {
+			continue
+		}
+
+		// Parse metric line: "metric_name value"
+		// Can also have labels like: metric_name{label="value"} value
+		parts := strings.Fields(line)
+		if len(parts) < 2 {
+			continue
+		}
+
+		metricName := parts[0]
+		// Remove any labels from metric name (everything after {)
+		if idx := strings.Index(metricName, "{"); idx != -1 {
+			metricName = metricName[:idx]
+		}
+
+		value, err := strconv.ParseFloat(parts[1], 64)
+		if err != nil {
+			// Skip lines that can't be parsed
+			continue
+		}
+
+		metrics[metricName] = value
+	}
+
+	if err := scanner.Err(); err != nil {
+		return nil, err
+	}
+
+	return metrics, nil
+}
+
+// displayEdmMetrics displays EDM-specific metrics in a table format
+func displayEdmMetrics(metrics map[string]float64) {
+	// Define the EDM metrics we want to display, in order
+	edmMetrics := []struct {
+		name        string
+		description string
+	}{
+		{"edm_processed_dnstap_total", "DNSTAP packets processed"},
+		{"edm_new_qname_queued_total", "New qname events queued"},
+		{"edm_new_qname_discarded_total", "New qname events discarded"},
+		{"edm_new_qname_ch_len", "New qname channel buffer length"},
+		{"edm_seen_qname_lru_evicted_total", "Qname LRU cache evictions"},
+		{"edm_cryptopan_lru_hit_total", "Crypto-PAn LRU cache hits"},
+		{"edm_cryptopan_lru_evicted_total", "Crypto-PAn LRU cache evictions"},
+		{"edm_ignored_client_ip_total", "Packets ignored (client IP filter)"},
+		{"edm_ignored_client_ip_error_total", "Client IP filter errors"},
+		{"edm_ignored_question_name_total", "Packets ignored (question name filter)"},
+	}
+
+	fmt.Println("EDM Statistics")
+	fmt.Println()
+
+	out := []string{"Metric|Value|Description"}
+
+	for _, metric := range edmMetrics {
+		value, exists := metrics[metric.name]
+		if exists {
+			// Format the metric name to remove "edm_" prefix for display
+			displayName := strings.TrimPrefix(metric.name, "edm_")
+
+			// Format value based on whether it's a counter or gauge
+			var valueStr string
+			if value == float64(int64(value)) {
+				// Integer value
+				valueStr = fmt.Sprintf("%d", int64(value))
+			} else {
+				// Float value
+				valueStr = fmt.Sprintf("%.2f", value)
+			}
+
+			out = append(out, fmt.Sprintf("%s|%s|%s",
+				displayName,
+				valueStr,
+				metric.description))
+		}
+	}
+
+	if len(out) == 1 {
+		fmt.Println("No EDM metrics found")
+		return
+	}
+
+	fmt.Printf("%s\n", columnize.SimpleFormat(out))
+}