debug nstat

Signed-off-by: bwplotka <bwplotka@gmail.com>

Author: bwplotka

examples/debug_netstat/main.go

@@ -0,0 +1,112 @@
+// Copyright The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// A debugging script using client_golang process collector code to reproduce and inspect
+// process_network_receive_bytes_total and process_network_transmit_bytes_total metrics,
+// specifically helping debug why network bytes may evaluate to 0 on macOS (darwin).
+package main
+
+import (
+	"fmt"
+	"io"
+	"log"
+	"net"
+	"net/http"
+	"os"
+	"runtime"
+	"time"
+
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/collectors"
+)
+
+func main() {
+	pid := os.Getpid()
+	fmt.Printf("=== Process Collector Network Bytes Debugger ===\n")
+	fmt.Printf("OS: %s, Architecture: %s, PID: %d\n\n", runtime.GOOS, runtime.GOARCH, pid)
+
+	// 1. Initial collection using client_golang ProcessCollector
+	reg := prometheus.NewRegistry()
+	collector := collectors.NewProcessCollector(collectors.ProcessCollectorOpts{})
+	reg.MustRegister(collector)
+
+	fmt.Println("--- 1. Initial Gathering from client_golang ProcessCollector ---")
+	gatherAndPrintNetworkMetrics(reg)
+
+	// 2. Generate active HTTP and TCP network traffic
+	fmt.Println("\n--- 2. Generating Active Network Traffic ---")
+	bytesSent, bytesRecv := generateNetworkTraffic()
+	fmt.Printf("Generated traffic: ~%d bytes sent, ~%d bytes received\n", bytesSent, bytesRecv)
+
+	// 3. Gathering from client_golang ProcessCollector after traffic
+	fmt.Println("\n--- 3. Post-Traffic Gathering from client_golang ProcessCollector ---")
+	gatherAndPrintNetworkMetrics(reg)
+
+	// 4. Low-level platform diagnostics
+	runPlatformDiagnostics(pid)
+}
+
+func gatherAndPrintNetworkMetrics(reg *prometheus.Registry) {
+	mfs, err := reg.Gather()
+	if err != nil {
+		log.Fatalf("Gather failed: %v", err)
+	}
+
+	foundMetrics := false
+	for _, mf := range mfs {
+		name := mf.GetName()
+		if name == "process_network_receive_bytes_total" || name == "process_network_transmit_bytes_total" {
+			foundMetrics = true
+			for _, m := range mf.GetMetric() {
+				if m.Counter != nil {
+					fmt.Printf("  %s: %.0f bytes\n", name, m.Counter.GetValue())
+				}
+			}
+		}
+	}
+	if !foundMetrics {
+		fmt.Println("  (network metrics not exposed on this platform)")
+	}
+}
+
+func generateNetworkTraffic() (int, int) {
+	handler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusOK)
+		w.Write([]byte("DEBUG_NETWORK_BYTES_RESPONSE"))
+	})
+	listener, err := net.Listen("tcp", "127.0.0.1:0")
+	if err != nil {
+		log.Printf("Failed to listen on local interface: %v", err)
+		return 0, 0
+	}
+	defer listener.Close()
+
+	server := &http.Server{Handler: handler}
+	go server.Serve(listener)
+	defer server.Close()
+
+	var sent, recv int
+	for i := 0; i < 10; i++ {
+		resp, err := http.Get("http://" + listener.Addr().String())
+		if err != nil {
+			log.Printf("HTTP request error: %v", err)
+			continue
+		}
+		body, _ := io.ReadAll(resp.Body)
+		resp.Body.Close()
+		recv += len(body)
+		sent += 50 // approximate request size
+	}
+	time.Sleep(100 * time.Millisecond)
+	return sent, recv
+}