Access Windows performance counters through Node.js.

1. Install cWinPerfCounter via NPM.

npm install cwinperfcounter

Optionally: rename cwinperfcounter to cWinPerfCounter: npm is unable to handle the complexity of uppercase characters in a module name. Node.js on Windows does not have this problem, so renaming the folder is not required for you to use the module.

2. Require cWinPerfCounter in your project.

var cWinPerfCounter=require("cWinPerfCounter");

3. Instantiate cWinPerfCounter for the performance counter you want to read.

var oPerfCounter = new cWinPerfCounter("\\Processor(_Total)\\% Processor Time");

4. Read values for the requested performance counter.

setInterval(function() {
  try {
    console.log(oPerfCounter.fnGetValue());
  } catch (oError) {
    console.log(oError);
  }
}, 1000);

This particular performance counter will return the average total CPU usage on your machine since the last time it was read. This means it will not return a value the first time you call it, but only after you have called it twice. The try ... catch will handle the error on the first read.

cWinPerfCounter comes with pre-build binaries for all supported processor architectures and Node.js versions (ia32 and x64, Node.js v0.9.0 - v0.12.0). These files are stored in separate sub-folders of the bin folder. The index.js attempts to load each .node file for the user's processor architecture until one works. This means it may attempt to load various versions that fail before it will eventually load the right version and return.

Future Node.js versions may be supported, if they can load the addon for the latest version included in this package. If the requirements for compiled addons change in a future version, an additional build of cWinPerfCounter.node will be required.

The build.cmd script will read a list of combinations of processor architecture and Node.js version from "build-targets.txt". It will build a cWinPerfCounter.node file for each of them and store it in its own sub-folder under the "bin" folder. You can also build a .node file for a single processor architecture and Node.js version by providing them as arguments to build.cmd, eg build.cmd x64 0.10.10.

You can either search the web, or you can run "perfmon.exe" on your machine and follow these steps:

• open Performance -> Monitoring Tools -> Performance Monitor,
• right-click on the graph and select "Add Counters...",
• select and add the counters you are interested in, then click "Ok".
• right-click the graph again and select "Properties...",
• in the "Data" tab, you will see a list of the names of the performance counters you have selected. You should be able to use these names with cWinPerfCounter.

This code is licensed under CC0 v1.0 Universal.