added media fixes, search, push updates, pwa, metrics. preparing release 1.0

server/internal/platform/metrics/metrics.go

@@ -0,0 +1,107 @@
+// Package metrics exposes Prometheus instrumentation for the HTTP API
+// and the realtime hub.
+package metrics
+
+import (
+	"net/http"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
+)
+
+var (
+	requestsTotal = prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Name: "messenger_http_requests_total",
+			Help: "HTTP requests handled, partitioned by method, normalized path and status.",
+		},
+		[]string{"method", "path", "status"},
+	)
+	requestDuration = prometheus.NewHistogramVec(
+		prometheus.HistogramOpts{
+			Name:    "messenger_http_request_duration_seconds",
+			Help:    "HTTP request latency.",
+			Buckets: prometheus.DefBuckets,
+		},
+		[]string{"method", "path"},
+	)
+	wsConnections = prometheus.NewGauge(
+		prometheus.GaugeOpts{
+			Name: "messenger_ws_connections",
+			Help: "Current number of open WebSocket connections.",
+		},
+	)
+	buildInfo = prometheus.NewGaugeVec(
+		prometheus.GaugeOpts{
+			Name: "messenger_build_info",
+			Help: "Build information.",
+		},
+		[]string{"version"},
+	)
+)
+
+// Init registers all custom metrics. The default registry already carries
+// the standard Go and process collectors.
+func Init(version string) {
+	prometheus.MustRegister(requestsTotal, requestDuration, wsConnections, buildInfo)
+	buildInfo.WithLabelValues(version).Set(1)
+}
+
+// Handler returns the Prometheus scrape endpoint.
+func Handler() http.Handler {
+	return promhttp.Handler()
+}
+
+// RecordWS increments or decrements the WebSocket connection gauge.
+func RecordWS(delta float64) {
+	wsConnections.Add(delta)
+}
+
+// Middleware instruments every request with counters and a latency histogram.
+func Middleware(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		start := time.Now()
+		rec := &recorder{ResponseWriter: w, status: http.StatusOK}
+		next.ServeHTTP(rec, r)
+		path := NormalizePath(r.URL.Path)
+		requestsTotal.WithLabelValues(r.Method, path, strconv.Itoa(rec.status)).Inc()
+		requestDuration.WithLabelValues(r.Method, path).Observe(time.Since(start).Seconds())
+	})
+}
+
+type recorder struct {
+	http.ResponseWriter
+	status int
+}
+
+func (r *recorder) WriteHeader(code int) {
+	r.status = code
+	r.ResponseWriter.WriteHeader(code)
+}
+
+// NormalizePath replaces numeric path segments with a placeholder so that
+// per-route cardinality stays bounded regardless of resource IDs.
+func NormalizePath(p string) string {
+	parts := strings.Split(p, "/")
+	for i, part := range parts {
+		if part != "" && isNumeric(part) {
+			parts[i] = "{id}"
+		}
+	}
+	return strings.Join(parts, "/")
+}
+
+func isNumeric(s string) bool {
+	if s == "" {
+		return false
+	}
+	for _, r := range s {
+		if r < '0' || r > '9' {
+			return false
+		}
+	}
+	return true
+}