pprof support for Node.js.

1. Your application will need to be using Node.js 18 or greater.

2. The pprof module has a native component that is used to collect profiles with v8's CPU and Heap profilers. You may need to install additional dependencies to build this module.

   • pprof has prebuilt binaries available for Linux arm64/x64, Alpine Linux x64, macOS arm64/x64, and Windows x64 for Node 18/20/22/24. No additional dependencies are required.
   • For other environments: on environments that pprof does not have prebuilt binaries for, the module node-gyp will be used to build binaries. See node-gyp's documentation for information on dependencies required to build binaries with node-gyp.

3. The pprof CLI can be used to view profiles collected with this module. Instructions for installing the pprof CLI can be found here.

Install pprof with npm or add to your package.json.

# Install through npm while saving to the local 'package.json'
npm install --save @datadog/pprof

1. Update code to collect and save a profile:

   const profile = await pprof.time.profile({
     durationMillis: 10000,    // time in milliseconds for which to
                               // collect profile.
   });
   const buf = await pprof.encode(profile);
   fs.writeFile('wall.pb.gz', buf, (err) => {
     if (err) throw err;
   });

2. View the profile with command line pprof:

   pprof -http=: wall.pb.gz

1. Start program from the command line:

   node --require @datadog/pprof app.js

2. A wall time profile for the job will be saved in pprof-profile-${process.pid}.pb.gz. View the profile with command line pprof:

   pprof -http=: pprof-profile-${process.pid}.pb.gz

1. Enable heap profiling at the start of the application:

   // The average number of bytes between samples.
   const intervalBytes = 512 * 1024;
   // The maximum stack depth for samples collected.
   const stackDepth = 64;
   heap.start(intervalBytes, stackDepth);

2. Collect heap profiles:

   • Collecting and saving a profile in profile.proto format:

     const profile = await pprof.heap.profile();
     const buf = await pprof.encode(profile);
     fs.writeFile('heap.pb.gz', buf, (err) => {
       if (err) throw err;
     })

   • View the profile with command line pprof.

     pprof -http=: heap.pb.gz

   • Collecting a heap profile with V8 allocation profile format:

       const profile = await pprof.heap.v8Profile();