Fix Node DEP0152 GC deprecation warning in SystemMetricsCollector

CHANGELOG.md

@@ -1,6 +1,10 @@
 
 # Changelog
 
+### v1.1.1 (GC Deprecation Fix)
+
+- **Fix Node DEP0152 deprecation warning in GC monitoring** - `SystemMetricsCollector._startGCMonitoring()` now reads GC kind from `entry.detail.kind` (with fallback to `entry.kind` for older Node versions) instead of the deprecated `entry.kind` accessor. Also fixes GC pause-time accounting: kinds are numeric constants (`NODE_PERFORMANCE_GC_MAJOR`, etc.), not string labels like `'major'` / `'minor'`.
+
 ### v1.1.0 (Mergebox RAM Residency Collector)
 
 - **New `MergeboxCollector`** - Measures Meteor's MERGEBOX RAM residency (the per-session, server-side cache of published documents) and posts per-(publication, collection) rollups to `POST /api/v1/metrics/mergebox`. The collector walks `Meteor.server.sessions` read-only, estimates the resident bytes each session's mergebox holds per published collection (sizing each `SessionDocumentView.dataByKey` field value directly), reads the publication strategy via `Meteor.server.getPublicationStrategy()` (reverse-mapped to all four Meteor strategies — `SERVER_MERGE` / `NO_MERGE` / `NO_MERGE_NO_HISTORY` / `NO_MERGE_MULTI`; `unknown` only when the strategy genuinely can't be read), and attributes residency to subscriptions via a pure even-split across `existsIn`. The even-split is sum-preserving: the rows for a collection sum back to that collection's true residency. `connectionCount` is a count of distinct DDP sessions (never a list of connection ids).

lib/collectors/SystemMetricsCollector.js

@@ -3,14 +3,20 @@ import os from "os";
 import fs from "fs/promises";
 import { exec } from "child_process";
 import { promisify } from "util";
-import { PerformanceObserver, performance } from "perf_hooks";
+import { PerformanceObserver, performance, constants } from "perf_hooks";
 import v8 from "v8";
 
 // Promisified exec for non-blocking command execution
 const execAsync = promisify(exec);
 
+const {
+  NODE_PERFORMANCE_GC_MAJOR,
+  NODE_PERFORMANCE_GC_MINOR,
+  NODE_PERFORMANCE_GC_INCREMENTAL,
+} = constants;
+
 // Agent version - must be updated alongside package.js on each release
-const AGENT_VERSION = '1.1.0';
+const AGENT_VERSION = '1.1.1';
 
 // cgroup v1 "unlimited" sentinel: values >= 2^62 mean no limit is set
 const CGROUP_V1_UNLIMITED = 2 ** 62;
@@ -937,6 +943,36 @@ export default class SystemMetricsCollector {
     return null;
   }
 
+  /**
+   * Resolve GC kind from a performance entry (Node DEP0152: use detail.kind).
+   * @param {PerformanceEntry} entry
+   * @returns {number|undefined}
+   * @private
+   */
+  _getGcKind(entry) {
+    return entry.detail?.kind ?? entry.kind;
+  }
+
+  /**
+   * Accumulate GC stats from a single performance entry.
+   * @param {PerformanceEntry} entry
+   * @private
+   */
+  _processGcEntry(entry) {
+    const kind = this._getGcKind(entry);
+
+    this.gcStats.count++;
+    this.gcStats.totalDuration += entry.duration;
+
+    if (kind === NODE_PERFORMANCE_GC_MAJOR || kind === NODE_PERFORMANCE_GC_MINOR) {
+      this.gcStats.totalPauseTime += entry.duration;
+    } else if (kind === NODE_PERFORMANCE_GC_INCREMENTAL) {
+      this.gcStats.totalPauseTime += entry.duration * 0.15;
+    } else {
+      this.gcStats.totalPauseTime += entry.duration * 0.5;
+    }
+  }
+
   /**
    * Start monitoring garbage collection events
    * Uses Node.js PerformanceObserver to track GC activity
@@ -947,26 +983,7 @@ export default class SystemMetricsCollector {
       // Create a PerformanceObserver to watch for GC events
       this.gcObserver = new PerformanceObserver((list) => {
         const entries = list.getEntries();
-
-        entries.forEach((entry) => {
-          // entry.kind: 'major', 'minor', 'incremental', 'weakcb', etc.
-          // entry.duration: Duration in milliseconds
-
-          this.gcStats.count++;
-          this.gcStats.totalDuration += entry.duration;
-
-          // For pause time, we use the duration since GC pauses the main thread
-          // Some GC types are incremental and have lower pause times
-          if (entry.kind === 'major' || entry.kind === 'minor') {
-            this.gcStats.totalPauseTime += entry.duration;
-          } else if (entry.kind === 'incremental') {
-            // Incremental GC has lower pause times (typically 10-20% of duration)
-            this.gcStats.totalPauseTime += entry.duration * 0.15;
-          } else {
-            // For other types, use half the duration as an estimate
-            this.gcStats.totalPauseTime += entry.duration * 0.5;
-          }
-        });
+        entries.forEach((entry) => this._processGcEntry(entry));
       });
 
       // Start observing GC events

package.js

@@ -1,6 +1,6 @@
 Package.describe({
   name: "skysignal:agent",
-  version: "1.1.0",
+  version: "1.1.1",
   summary:
     "SkySignal APM agent for Meteor applications - monitors performance, errors, and system metrics",
   git: "https://github.com/skysignalapm/agent.git",

tests/unit/collectors/SystemMetricsCollector.test.js

@@ -8,8 +8,15 @@
 
 import { expect } from 'chai';
 import sinon from 'sinon';
+import { constants } from 'perf_hooks';
 import SystemMetricsCollector from '../../../lib/collectors/SystemMetricsCollector.js';
 
+const {
+  NODE_PERFORMANCE_GC_MAJOR,
+  NODE_PERFORMANCE_GC_MINOR,
+  NODE_PERFORMANCE_GC_INCREMENTAL,
+} = constants;
+
 describe('SystemMetricsCollector', function () {
 
   let collector;
@@ -177,6 +184,41 @@ describe('SystemMetricsCollector', function () {
     });
   });
 
+  // ==========================================
+  // _getGcKind
+  // ==========================================
+  describe('_getGcKind', function () {
+
+    it('reads kind from entry.detail when present', function () {
+      const entry = { detail: { kind: NODE_PERFORMANCE_GC_MAJOR } };
+      expect(collector._getGcKind(entry)).to.equal(NODE_PERFORMANCE_GC_MAJOR);
+    });
+
+    it('falls back to entry.kind for older Node entries', function () {
+      const entry = { kind: NODE_PERFORMANCE_GC_MINOR };
+      expect(collector._getGcKind(entry)).to.equal(NODE_PERFORMANCE_GC_MINOR);
+    });
+  });
+
+  // ==========================================
+  // _processGcEntry
+  // ==========================================
+  describe('_processGcEntry', function () {
+
+    it('accumulates pause time using numeric GC kinds from entry.detail', function () {
+      collector.gcStats = { count: 0, totalDuration: 0, totalPauseTime: 0 };
+
+      collector._processGcEntry({ duration: 10, detail: { kind: NODE_PERFORMANCE_GC_MAJOR } });
+      collector._processGcEntry({ duration: 8, detail: { kind: NODE_PERFORMANCE_GC_MINOR } });
+      collector._processGcEntry({ duration: 6, detail: { kind: NODE_PERFORMANCE_GC_INCREMENTAL } });
+      collector._processGcEntry({ duration: 4, detail: { kind: 99 } });
+
+      expect(collector.gcStats.count).to.equal(4);
+      expect(collector.gcStats.totalDuration).to.equal(28);
+      expect(collector.gcStats.totalPauseTime).to.equal(10 + 8 + (6 * 0.15) + (4 * 0.5));
+    });
+  });
+
   // ==========================================
   // start / stop
   // ==========================================