perf: bound runtime memory and storage usage

back/services/metrics.ts

@@ -8,16 +8,19 @@ interface Metric {
   tags?: Record<string, string>;
 }
 
-class MetricsService {
-  private metrics: Metric[] = [];
+export const MAX_METRIC_SAMPLES = 1000;
+const METRIC_RETENTION_MS = 60 * 60 * 1000;
+
+export class MetricsService {
+  private metrics: Array<Metric | undefined> = new Array(MAX_METRIC_SAMPLES);
+  private metricCount = 0;
+  private nextMetricIndex = 0;
   private static instance: MetricsService;
 
   private constructor() {
     // 定期清理旧数据
-    setInterval(() => {
-      const oneHourAgo = Date.now() - 3600000;
-      this.metrics = this.metrics.filter(m => m.timestamp > oneHourAgo);
-    }, 60000);
+    const cleanupTimer = setInterval(() => this.removeExpiredMetrics(), 60000);
+    cleanupTimer.unref();
   }
 
   static getInstance(): MetricsService {
@@ -28,12 +31,14 @@ class MetricsService {
   }
 
   record(name: string, value: number, tags?: Record<string, string>) {
-    this.metrics.push({
+    this.metrics[this.nextMetricIndex] = {
       name,
       value,
       timestamp: Date.now(),
       tags,
-    });
+    };
+    this.nextMetricIndex = (this.nextMetricIndex + 1) % MAX_METRIC_SAMPLES;
+    this.metricCount = Math.min(this.metricCount + 1, MAX_METRIC_SAMPLES);
   }
 
   measure(name: string, fn: () => void, tags?: Record<string, string>) {
@@ -46,7 +51,11 @@ class MetricsService {
     }
   }
 
-  async measureAsync(name: string, fn: () => Promise<void>, tags?: Record<string, string>) {
+  async measureAsync(
+    name: string,
+    fn: () => Promise<void>,
+    tags?: Record<string, string>,
+  ) {
     const start = performance.now();
     try {
       await fn();
@@ -57,28 +66,61 @@ class MetricsService {
   }
 
   getMetrics(name?: string, tags?: Record<string, string>) {
-    let filtered = this.metrics;
-    
+    this.removeExpiredMetrics();
+    let filtered = this.getMetricSnapshot();
+
     if (name) {
-      filtered = filtered.filter(m => m.name === name);
+      filtered = filtered.filter((m) => m.name === name);
     }
-    
+
     if (tags) {
-      filtered = filtered.filter(m => {
+      filtered = filtered.filter((m) => {
         if (!m.tags) return false;
-        return Object.entries(tags).every(([key, value]) => m.tags![key] === value);
+        return Object.entries(tags).every(
+          ([key, value]) => m.tags![key] === value,
+        );
       });
     }
 
+    const values = filtered.map((metric) => metric.value);
     return {
       count: filtered.length,
-      average: filtered.reduce((acc, curr) => acc + curr.value, 0) / filtered.length,
-      min: Math.min(...filtered.map(m => m.value)),
-      max: Math.max(...filtered.map(m => m.value)),
+      average: values.length
+        ? values.reduce((acc, value) => acc + value, 0) / values.length
+        : 0,
+      min: values.length ? Math.min(...values) : 0,
+      max: values.length ? Math.max(...values) : 0,
       metrics: filtered,
     };
   }
 
+  private getMetricSnapshot(): Metric[] {
+    if (this.metricCount < MAX_METRIC_SAMPLES) {
+      return this.metrics.slice(0, this.metricCount) as Metric[];
+    }
+    return [
+      ...this.metrics.slice(this.nextMetricIndex),
+      ...this.metrics.slice(0, this.nextMetricIndex),
+    ] as Metric[];
+  }
+
+  private removeExpiredMetrics() {
+    const oldestTimestamp = Date.now() - METRIC_RETENTION_MS;
+    const retained = this.getMetricSnapshot().filter(
+      (metric) => metric.timestamp > oldestTimestamp,
+    );
+    if (retained.length === this.metricCount) return;
+
+    this.metrics = new Array(MAX_METRIC_SAMPLES);
+    this.metricCount = 0;
+    this.nextMetricIndex = 0;
+    for (const metric of retained) {
+      this.metrics[this.nextMetricIndex] = metric;
+      this.nextMetricIndex = (this.nextMetricIndex + 1) % MAX_METRIC_SAMPLES;
+      this.metricCount++;
+    }
+  }
+
   report() {
     const report = {
       timestamp: Date.now(),
@@ -89,4 +131,4 @@ class MetricsService {
   }
 }
 
-export const metricsService = MetricsService.getInstance(); 
+export const metricsService = MetricsService.getInstance();