new node.js impl., removed old stuff

email-worker-nodejs/metrics.ts

@@ -0,0 +1,155 @@
+/**
+ * Prometheus metrics collection
+ *
+ * Uses prom-client. Falls back gracefully if not available.
+ */
+
+import { log } from './logger.js';
+import type * as PromClientTypes from 'prom-client';
+
+// prom-client is optional — import dynamically
+let promClient: typeof PromClientTypes | null = null;
+try {
+  promClient = require('prom-client') as typeof PromClientTypes;
+} catch {
+  // not installed
+}
+
+// ---------------------------------------------------------------------------
+// Metric instances (created lazily if prom-client is available)
+// ---------------------------------------------------------------------------
+let emailsProcessed: any;
+let emailsInFlight: any;
+let processingTime: any;
+let queueSize: any;
+let bouncesProcessed: any;
+let autorepliesSent: any;
+let forwardsSent: any;
+let blockedSenders: any;
+
+function initMetrics(): void {
+  if (!promClient) return;
+  const { Counter, Gauge, Histogram } = promClient;
+
+  emailsProcessed = new Counter({
+    name: 'emails_processed_total',
+    help: 'Total emails processed',
+    labelNames: ['domain', 'status'],
+  });
+  emailsInFlight = new Gauge({
+    name: 'emails_in_flight',
+    help: 'Emails currently being processed',
+  });
+  processingTime = new Histogram({
+    name: 'email_processing_seconds',
+    help: 'Time to process email',
+    labelNames: ['domain'],
+  });
+  queueSize = new Gauge({
+    name: 'queue_messages_available',
+    help: 'Messages in queue',
+    labelNames: ['domain'],
+  });
+  bouncesProcessed = new Counter({
+    name: 'bounces_processed_total',
+    help: 'Bounce notifications processed',
+    labelNames: ['domain', 'type'],
+  });
+  autorepliesSent = new Counter({
+    name: 'autoreplies_sent_total',
+    help: 'Auto-replies sent',
+    labelNames: ['domain'],
+  });
+  forwardsSent = new Counter({
+    name: 'forwards_sent_total',
+    help: 'Forwards sent',
+    labelNames: ['domain'],
+  });
+  blockedSenders = new Counter({
+    name: 'blocked_senders_total',
+    help: 'Emails blocked by blacklist',
+    labelNames: ['domain'],
+  });
+}
+
+// ---------------------------------------------------------------------------
+// MetricsCollector
+// ---------------------------------------------------------------------------
+export class MetricsCollector {
+  public readonly enabled: boolean;
+
+  constructor() {
+    this.enabled = !!promClient;
+    if (this.enabled) initMetrics();
+  }
+
+  incrementProcessed(domain: string, status: string): void {
+    emailsProcessed?.labels(domain, status).inc();
+  }
+
+  incrementInFlight(): void {
+    emailsInFlight?.inc();
+  }
+
+  decrementInFlight(): void {
+    emailsInFlight?.dec();
+  }
+
+  observeProcessingTime(domain: string, seconds: number): void {
+    processingTime?.labels(domain).observe(seconds);
+  }
+
+  setQueueSize(domain: string, size: number): void {
+    queueSize?.labels(domain).set(size);
+  }
+
+  incrementBounce(domain: string, bounceType: string): void {
+    bouncesProcessed?.labels(domain, bounceType).inc();
+  }
+
+  incrementAutoreply(domain: string): void {
+    autorepliesSent?.labels(domain).inc();
+  }
+
+  incrementForward(domain: string): void {
+    forwardsSent?.labels(domain).inc();
+  }
+
+  incrementBlocked(domain: string): void {
+    blockedSenders?.labels(domain).inc();
+  }
+}
+
+// ---------------------------------------------------------------------------
+// Start metrics HTTP server
+// ---------------------------------------------------------------------------
+export async function startMetricsServer(port: number): Promise<MetricsCollector | null> {
+  if (!promClient) {
+    log('⚠ Prometheus client not installed, metrics disabled', 'WARNING');
+    return null;
+  }
+
+  try {
+    const { createServer } = await import('node:http');
+    const { register } = promClient;
+
+    const server = createServer(async (_req, res) => {
+      try {
+        res.setHeader('Content-Type', register.contentType);
+        res.end(await register.metrics());
+      } catch {
+        res.statusCode = 500;
+        res.end();
+      }
+    });
+
+    server.listen(port, () => {
+      log(`Prometheus metrics on port ${port}`);
+    });
+
+    return new MetricsCollector();
+  } catch (err: any) {
+    log(`Failed to start metrics server: ${err.message ?? err}`, 'ERROR');
+    return null;
+  }
+}