feat: add muxer job queue with SQLite integration and metrics tracking

src/metrics.ts

@@ -0,0 +1,78 @@
+import { Counter, Gauge, Histogram, register } from "prom-client";
+
+// Audio metrics
+export const audioLevelGauge = new Gauge({
+  name: "audio_level_db",
+  help: "Current audio level in dB",
+  labelNames: ["user_id"],
+});
+
+export const recordingDurationCounter = new Counter({
+  name: "recording_duration_seconds_total",
+  help: "Total recording duration in seconds",
+  labelNames: ["user_id"],
+});
+
+export const activeRecordingsGauge = new Gauge({
+  name: "active_recordings",
+  help: "Number of active recordings",
+});
+
+export const recordedSegmentsCounter = new Counter({
+  name: "recorded_segments_total",
+  help: "Total number of recorded segments",
+  labelNames: ["user_id"],
+});
+
+// Connection metrics
+export const voiceConnectionsGauge = new Gauge({
+  name: "voice_connections_active",
+  help: "Number of active voice connections",
+});
+
+export const connectionErrorsCounter = new Counter({
+  name: "connection_errors_total",
+  help: "Total number of connection errors",
+  labelNames: ["error_type"],
+});
+
+export const reconnectAttemptsCounter = new Counter({
+  name: "reconnect_attempts_total",
+  help: "Total number of reconnection attempts",
+});
+
+// WebSocket metrics
+export const wsClientsGauge = new Gauge({
+  name: "websocket_clients_connected",
+  help: "Number of connected WebSocket clients",
+});
+
+export const wsMessagesCounter = new Counter({
+  name: "websocket_messages_total",
+  help: "Total WebSocket messages sent",
+  labelNames: ["message_type"],
+});
+
+// HTTP metrics
+export const httpRequestDurationHistogram = new Histogram({
+  name: "http_request_duration_seconds",
+  help: "HTTP request duration in seconds",
+  labelNames: ["method", "route", "status"],
+  buckets: [0.001, 0.01, 0.1, 0.5, 1, 2, 5],
+});
+
+export const httpRequestsCounter = new Counter({
+  name: "http_requests_total",
+  help: "Total HTTP requests",
+  labelNames: ["method", "route", "status"],
+});
+
+// System metrics
+export const uptimeGauge = new Gauge({
+  name: "process_uptime_seconds",
+  help: "Process uptime in seconds",
+});
+
+export async function getMetrics(): Promise<string> {
+  return register.metrics();
+}