@musicglue/async-hook

#async-hook

Inspect the life of handle objects in node

Documentation

This is high level abstraction of the currently undocumented node API called AsyncWrap. It patches some issues, makes the API more uniform and allows multiply hooks to be created.

I personally hope that most of this will make it into nodecore, but for now it exists as an userland module.

For the details of how AsyncWrap works and by extension how this module works, please see the semi-official AsyncWrap documentation: https://github.com/nodejs/tracing-wg/blob/master/docs/AsyncWrap/README.md

const asyncHook = require('async-hook');

Hooks

The function arguments are:

function init(uid, handle, provider, parentUid, parentHandle) { /* your code */ }
function pre(uid, handle) {  /* your code */ }
function post(uid, handle) {  /* your code */ }
function destroy(uid) {  /* your code */ }

To add hooks:

asyncHook.addHooks({ init, pre, post, destroy });

To remove hooks:

asyncHooks.removeHooks({ init, pre, post, destroy });

All properties in the hooks object that addHooks and removeHooks takes are optional.

Providers

The providers map is exposed as:

asyncHook.providers[provider];

Enable and disable

You can enable and disable all hooks by using asyncHook.enable() and asyncHook.disable(). By default it is disabled.

Be careful about disabling the hooks, this will most likely conflict with other modules that uses async-hook.