backups: periodically dump heap space info

src/scripts/backupupload.js

@@ -12,7 +12,8 @@ var assert = require('assert'),
     backups = require('../backups.js'),
     database = require('../database.js'),
     debug = require('debug')('box:backupupload'),
-    settings = require('../settings.js');
+    settings = require('../settings.js'),
+    v8 = require('v8');
 
 function initialize(callback) {
     assert.strictEqual(typeof callback, 'function');
@@ -52,13 +53,27 @@ function throttledProgressCallback(msecs) {
     };
 }
 
+// https://github.com/josefzamrzla/gc-heap-stats#readme
+// https://stackoverflow.com/questions/41541843/nodejs-v8-getheapstatistics-method
+function dumpMemoryInfo() {
+    const mu = process.memoryUsage();
+    const hs = v8.getHeapStatistics();
+
+    debug(`v8 heap : used ${hs.used_heap_size} total: ${hs.total_heap_size} max: ${hs.heap_size_limit}`);
+    debug(`process: rss: ${mu.rss} heapTotal: ${mu.heapTotal} heapUsed: ${mu.heapUsed} external: ${mu.external}`);
+}
+
 initialize(function (error) {
     if (error) throw error;
 
+    dumpMemoryInfo();
+    const timerId = setInterval(dumpMemoryInfo, 30000);
+
     backups.upload(backupId, format, dataLayoutString, throttledProgressCallback(5000), function resultHandler(error) {
         debug('upload completed. error: ', error);
 
         process.send({ result: error ? error.message : '' });
+        clearInterval(timerId);
 
         // https://nodejs.org/api/process.html are exit codes used by node. apps.js uses the value below
         // to check apptask crashes