heimdalljsheimdall-fs-monitor
file system monitor plugin for heimdalljs
Installation
npm install --save-dev heimdalljs-fs-monitor
Usage
const FSMonitor = require('heimdalljs-fs-monitor');
// create a new file system monitor
const monitor = new FSMonitor();
// start monitoring
monitor.start();
// ... do some file system work ...
var fs = require('fs');
fs.readFileSync('package.json');
// stop monitoring
monitor.stop();
// read file system call stats
const heimdall = require('heimdalljs');
const stats = heimdall.statsFor('fs');
Getting invocation stacks
In order to get more information about where fs calls are coming from, simply adding an environment variable called HEIMDALL_FS_MONITOR_CALL_TRACING and setting that to 1 will add an invocation object to the fs.stats[{fsFunctionName}] object. This could be a potential place where memory backpressure will occur, as this will continue to grow during a build. Since we are not storing every invocation as an entry in an array, and instead just increasing the count for a particular stack trace, this should only be used when needed.
process.env.HEIMDALL_FS_MONITOR_CALL_TRACING = 1;
const FSMonitor = require('heimdalljs-fs-monitor');
// create a new file system monitor
const monitor = new FSMonitor();
// start monitoring
monitor.start();
// ... do some file system work ...
var fs = require('fs');
fs.readFileSync('package.json');
// stop monitoring
monitor.stop();
Accessing heimdall.fs.stats.readFileSync, for example will yeild a Metric object that looks like the following:
{
count: 1,
time: 821855,
invocations: {
' at Object.readFileSync (~/heimdall-fs-monitor/index.js:112:35)\n at Context.<anonymous> (~/heimdall-fs-monitor/tests.js:89:8)\n at callFn (~/heimdall-fs-monitor/node_modules/mocha/lib/runnable.js:370:21)\n at Test.Runnable.run (~/heimdall-fs-monitor/node_modules/mocha/lib/runnable.js:357:7)\n at Runner.runTest (~/heimdall-fs-monitor/node_modules/mocha/lib/runner.js:541:10)\n at ~/heimdall-fs-monitor/node_modules/mocha/lib/runner.js:667:12\n at next (~/heimdall-fs-monitor/node_modules/mocha/lib/runner.js:450:14)\n at ~/heimdall-fs-monitor/node_modules/mocha/lib/runner.js:460:7\n at next (~/heimdall-fs-monitor/node_modules/mocha/lib/runner.js:362:14)\n at Immediate._onImmediate (~/heimdall-fs-monitor/node_modules/mocha/lib/runner.js:428:5)': {
lineNumber: 89,
fileName: '~/heimdall-fs-monitor/tests.js',
count: 1
}
}
}
License
heimdall-fs-monitor is licensed under the ISC License.