added event loop metrics

Author: piotrek98

lib/node/helpers.ts

@@ -21,6 +21,9 @@ export const getOsPlatform = (): Platform => {
   };
 };
 
+export const toDecimalNumber = (val: number, decimal: number = 2) =>
+  Number(val.toFixed(decimal));
+
 // export const sanitizeDsn = (dsn: string) => {
 //   const [secretKey, rest] = dsn
 //     .replace("http://", "")

lib/node/metrics.ts

@@ -5,6 +5,8 @@ import { cpu } from "./metrics/cpu-usage";
 import * as os from "node:os";
 import { memory } from "./metrics/memory-usage";
 import { heap } from "./metrics/heap";
+import { eventLoop } from "./metrics/event-loop";
+import { toDecimalNumber } from "./helpers";
 
 const DEFAULT_INTERVAL = 30; //seconds
 
@@ -18,8 +20,9 @@ const collectMetrics = (options: TraceoOptions) => {
     const metrics: Metrics = {
       cpuUsage: cpu.usage(),
       memory: memory.usage(),
-      loadAvg: Number(os.loadavg()[0].toFixed(2)) || 0,
+      loadAvg: toDecimalNumber(os.loadavg()[0]),
       heap,
+      eventLoopLag: eventLoop.collect(),
     };
 
     const httpModule = new HttpModule("/api/worker/metrics", metrics);

lib/node/metrics/event-loop.ts

@@ -0,0 +1,25 @@
+import * as perf_hooks from "perf_hooks";
+import { Metrics } from "../../transport/metrics";
+import { toDecimalNumber } from "../helpers";
+
+const histogram = perf_hooks.monitorEventLoopDelay({
+  resolution: 10,
+});
+histogram.enable();
+
+const collect = () => {
+  const data: Metrics["eventLoopLag"] = {
+    min: toDecimalNumber(histogram.min / 1e6),
+    max: toDecimalNumber(histogram.max / 1e6),
+    mean: toDecimalNumber(histogram.mean / 1e6),
+    stddev: toDecimalNumber(histogram.stddev / 1e6),
+    p50: toDecimalNumber(histogram.percentile(50) / 1e6),
+    p90: toDecimalNumber(histogram.percentile(90) / 1e6),
+    p99: toDecimalNumber(histogram.percentile(99) / 1e6),
+  };
+  histogram.reset();
+
+  return data;
+};
+
+export const eventLoop = { collect };

lib/node/metrics/heap.ts

@@ -1,4 +1,6 @@
 import * as v8 from "v8";
+import { Metrics } from "../../transport/metrics";
+import { toDecimalNumber } from "../helpers";
 
 /**
  * https://www.geeksforgeeks.org/node-js-v8-getheapstatistics-method/
@@ -14,10 +16,10 @@ const getNumberOfNativeContexts = () =>
 const getNumberOfDetachedContexts = () =>
   getHeapStatistics().number_of_detached_contexts;
 
-export const heap = {
-  used: Number((process.memoryUsage().heapUsed / TO_MB).toFixed(2)),
-  total: Number((process.memoryUsage().heapTotal / TO_MB).toFixed(2)),
-  rss: Number((process.memoryUsage().rss / TO_MB).toFixed(2)),
+export const heap: Metrics['heap'] = {
+  used: toDecimalNumber(process.memoryUsage().heapUsed / TO_MB),
+  total: toDecimalNumber(process.memoryUsage().heapTotal / TO_MB),
+  rss: toDecimalNumber(process.memoryUsage().rss / TO_MB),
   nativeContexts: getNumberOfNativeContexts(),
   detachedContexts: getNumberOfDetachedContexts(),
 };

lib/node/metrics/memory-usage.ts

@@ -1,11 +1,12 @@
 import * as os from "node:os";
+import { toDecimalNumber } from "../helpers";
 
 const usage = () => {
   const freeMemory = Math.round(os.freemem() / 1024 / 1024);
   const totalMemory = Math.round(os.totalmem() / 1024 / 1024);
 
   const usedMemory = Math.round(totalMemory - freeMemory);
-  const percentageUsed = Number(((usedMemory / totalMemory) * 100).toFixed(2));
+  const percentageUsed = toDecimalNumber((usedMemory / totalMemory) * 100);
 
   return {
     mb: usedMemory,

lib/transport/metrics.ts

@@ -12,4 +12,13 @@ export interface Metrics {
     nativeContexts: number;
     detachedContexts: number;
   };
+  eventLoopLag: {
+    min: number;
+    max: number;
+    mean: number;
+    stddev: number;
+    p50: number;
+    p90: number;
+    p99: number;
+  };
 }

package.json

@@ -1,6 +1,6 @@
 {
   "name": "traceo-sdk",
-  "version": "0.3.4-beta",
+  "version": "0.3.6-beta",
   "license": "MIT",
   "main": "dist/index.js",
   "types": "dist/index.d.ts",