Pyroscope nodejs package

Running Pyroscope server

In order to send data from your node application to Pyroscope, you'll first need to run the Pyroscope server. If on a mac you can simply do this with

# install pyroscope
brew install pyroscope-io/brew/pyroscope

# start pyroscope server:
pyroscope server

or if not then see the documentation for more info on how to start the server.

Configuration

| env var | default | description | | ----------------------------- | ----------------------- | -------------------------------------------------------------------- | | PYROSCOPE_SAMPLING_INTERVAL | 10 | The interval in milliseconds between samples. | | PYROSCOPE_SAMPLING_DURATION | 10000 (10s) | The duration in milliseconds for which you want to collect a sample. | | PYROSCOPE_SERVER_ADDRESS | http://localhost:4040 | The address of the Pyroscope server. | | PYROSCOPE_APPLICATION_NAME | "" | The application name used when uploading profiling data. | | PYROSCOPE_AUTH_TOKEN | N/A | The authorization token used to upload profiling data. |

Modes

Pyroscope supports two main operation modes:

• Push mode
• Pull mode

Push mode means the package itself uploads profile data to a pyroscope server, when pull mode means you provide pyroscope server with an endponts to scrape profile data

NodeJS Pyroscope module supports collecting wall-time and heap. More details you may find here

Push mode

Usage is differs for first you need to import and init pyroscope module. Module is available for both CommonJS and ESM variants, so you can use it the way it fits your project.

Javascript

const Pyroscope = require('pyroscope');

Pyroscope.init({serverAddress: 'http://pyroscope:4040', appName: 'nodejs'});
Pyroscope.start()

Typescript:

import Pyroscope from 'pyroscope';

Pyroscope.init({serverAddress: 'http://pyroscope:4040', appName: 'nodejs'});
Pyroscope.start()

Both params appName and serverAddress are mandatory. Once you init you may startCpuProfiling() and/or startHeapProfiling(). start() starts both memory and CPU profiling

Pull Mode

In order to enable pull mode you need to implement follwing endpoints:

• /debug/pprof/profile -- for wall-time profiling
• /debug/pprof/heap -- for heap profiling

You may implement your own enpoints with Pyroscope API, like in the example:

Pyroscope.init()

app.get('/debug/pprof/profile', async function handler(req, res) {
  console.log('Collecting Cpu for', req.query.seconds);
  try {
    const p = await Pyroscope.collectCpu(req.query.seconds);
    res.send(p);
  } catch (e) {
    console.error('Error collecting cpu', e);
    res.sendStatus(500);
  }
});

Parameter appName is mandatory in pull mode.

Pull Mode

In order to enable pull mode you need to implement follwing endpoints:

• /debug/pprof/profile -- for wall-time profiling
• /debug/pprof/heap -- for heap profiling

You may implement your own enpoints with Pyroscope API, like in the example:

app.get('/debug/pprof/profile', async function handler(req, res) {
  console.log('Collecting Cpu for', req.query.seconds);
  try {
    const p = await Pyroscope.collectCpu(req.query.seconds);
    res.send(p);
  } catch (e) {
    console.error('Error collecting cpu', e);
    res.sendStatus(500);
  }
});

or you may use express middleware.

import Pyroscope, { expressMiddleware } from '@pyroscope/nodejs'

Pyroscope.init()
const app = express()
app.use(expressMiddleware());

then you also need to configure your pyroscope server by providing config file

---
log-level: debug
scrape-configs:
  - job-name: testing            # any name 
    enabled-profiles: [cpu, mem] # cpu and mem for wall and heap
    static-configs:
      - application: rideshare
        spy-name: nodespy        # make pyroscope know it's node profiles
        targets:
          - localhost:3000       # address of your scrape target
        labels:     
          env: dev               # labels

Debugging

Use DEBUG env var set to pyroscope to enable debugging messages. Otherwise all messages will be suppressed.

DEBUG=pyroscope node index.js

API

Configuration

init(c : PyroscopeConfig)

Configuration options

interface PyroscopeConfig {
    serverAddress?: string;          // Server address for push mode
    sourceMapPath?: string[];       // Sourcemaps directories (optional)
    appName?: string;                // Application name
    tags?: Record<string, any>;     // Tags 
    authToken?: string              // Auth token for cloud version
}

Both serverAddress and appName are mandatory for push mode.

CPU Profiling

// Start collecting for 10s and push to server
Pyroscope.startCpuProfiling()
Pyroscope.stopCpuProfiling()

// Or do it manually
Pyroscope.collectCpu(seconds?:number);

Heap Profiling

// Start heap profiling and upload to server
Pyroscope.startHeapProfiling()
Pyroscope.stopHeapProfiling()

// Or do it manually
Pyroscope.startHeapCollecting()
Pyroscope.collectHeap();
Pyroscope.stopHeapCollecting()