Capture CPU and memory metrics (#188)

* Capture CPU/memory metrics

* Fix

Author: itssimon

src/common/client.ts

@@ -6,6 +6,7 @@ import { Logger, getLogger } from "./logging.js";
 import { isValidClientId, isValidEnv } from "./paramValidation.js";
 import RequestCounter from "./requestCounter.js";
 import RequestLogger from "./requestLogger.js";
+import { getCpuMemoryUsage } from "./resources.js";
 import ServerErrorCounter from "./serverErrorCounter.js";
 import {
   ApitallyConfig,
@@ -225,6 +226,7 @@ export class ApitallyClient {
         this.validationErrorCounter.getAndResetValidationErrors(),
       server_errors: this.serverErrorCounter.getAndResetServerErrors(),
       consumers: this.consumerRegistry.getAndResetUpdatedConsumers(),
+      resources: getCpuMemoryUsage(),
     };
     this.syncDataQueue.push(newPayload);
 

src/common/resources.ts

@@ -0,0 +1,35 @@
+let lastCpuUsage: { user: number; system: number } | null = null;
+let lastCpuTime: number | null = null;
+
+export function getCpuMemoryUsage() {
+  const currentCpuUsage = process.cpuUsage();
+  const currentTime = performance.now();
+  const memoryRss = process.memoryUsage().rss;
+
+  let cpuPercent = null;
+
+  if (lastCpuUsage !== null && lastCpuTime !== null) {
+    // Calculate elapsed time in microseconds
+    const elapsedTime = (currentTime - lastCpuTime) * 1000;
+
+    // Calculate CPU time used (user + system) in microseconds
+    const cpuTime =
+      currentCpuUsage.user -
+      lastCpuUsage.user +
+      (currentCpuUsage.system - lastCpuUsage.system);
+
+    // Calculate percentage
+    cpuPercent = (cpuTime / elapsedTime) * 100;
+  }
+
+  // Update last values for next call
+  lastCpuUsage = currentCpuUsage;
+  lastCpuTime = currentTime;
+
+  return cpuPercent !== null
+    ? {
+        cpu_percent: cpuPercent,
+        memory_rss: memoryRss,
+      }
+    : null;
+}

src/common/types.ts

@@ -94,4 +94,8 @@ export type SyncPayload = {
   validation_errors: Array<ValidationErrorsItem>;
   server_errors: Array<ServerErrorsItem>;
   consumers: Array<ConsumerItem>;
+  resources: {
+    cpu_percent: number;
+    memory_rss: number;
+  } | null;
 };