https://github.com/Tapppi/async-exit-hook
Run some code when the process exits
https://github.com/Tapppi/async-exit-hook
async es6 exit node process sigint signal sigterm
Last synced: 12 months ago
JSON representation
Run some code when the process exits
- Host: GitHub
- URL: https://github.com/Tapppi/async-exit-hook
- Owner: Tapppi
- License: mit
- Fork: true (sindresorhus/exit-hook)
- Created: 2016-03-07T11:18:27.000Z (about 10 years ago)
- Default Branch: master
- Last Pushed: 2021-06-15T13:34:48.000Z (almost 5 years ago)
- Last Synced: 2024-10-31T00:50:35.876Z (over 1 year ago)
- Topics: async, es6, exit, node, process, sigint, signal, sigterm
- Language: JavaScript
- Size: 87.9 KB
- Stars: 118
- Watchers: 5
- Forks: 15
- Open Issues: 11
-
Metadata Files:
- Readme: readme.md
- Changelog: CHANGELOG.md
- License: license
Awesome Lists containing this project
README
# async-exit-hook
[](https://travis-ci.org/Tapppi/async-exit-hook)
[](https://coveralls.io/github/Tapppi/async-exit-hook?branch=master)
> Run some code when the process exits
The `process.on('exit')` event doesn't catch all the ways a process can exit. This module catches:
* process SIGINT, SIGTERM and SIGHUP, SIGBREAK signals
* process beforeExit and exit events
* PM2 clustering process shutdown message ([PM2 graceful reload](http://pm2.keymetrics.io/docs/usage/cluster-mode/#graceful-reload))
Useful for cleaning up. You can also include async handlers, and add custom events to hook and exit on.
Forked and pretty much rewritten from [exit-hook](https://npmjs.com/package/exit-hook).
## Install
```
$ npm install --save async-exit-hook
```
## Usage
### Considerations and warning
#### On `process.exit()` and asynchronous code
**If you use asynchronous exit hooks, DO NOT use `process.exit()` to exit.
The `exit` event DOES NOT support asynchronous code.**
>['beforeExit' is not emitted for conditions causing explicit termination, such as process.exit()]
(https://nodejs.org/api/process.html#process_event_beforeexit)
#### Windows and `process.kill(signal)`
On windows `process.kill(signal)` immediately kills the process, and does not fire signal events,
and as such, cannot be used to gracefully exit. See *Clustering and child processes* for a
workaround when killing child processes. I'm planning to support gracefully exiting
with async support on windows soon.
### Clustering and child processes
If you use custom clustering / child processes, you can gracefully shutdown your child process
by sending a shutdown message (`childProc.send('shutdown')`).
### Example
```js
const exitHook = require('async-exit-hook');
exitHook(() => {
console.log('exiting');
});
// you can add multiple hooks, even across files
exitHook(() => {
console.log('exiting 2');
});
// you can add async hooks by accepting a callback
exitHook(callback => {
setTimeout(() => {
console.log('exiting 3');
callback();
}, 1000);
});
// You can hook uncaught errors with uncaughtExceptionHandler(), consequently adding
// async support to uncaught errors (normally uncaught errors result in a synchronous exit).
exitHook.uncaughtExceptionHandler(err => {
console.error(err);
});
// You can hook unhandled rejections with unhandledRejectionHandler()
exitHook.unhandledRejectionHandler(err => {
console.error(err);
});
// You can add multiple uncaught error handlers
// Add the second parameter (callback) to indicate async hooks
exitHook.uncaughtExceptionHandler((err, callback) => {
sendErrorToCloudOrWhatever(err) // Returns promise
.then(() => {
console.log('Sent err to cloud');
})
.catch(sendError => {
console.error('Error sending to cloud: ', err.stack);
})
.then(() => callback);
});
// Add exit hooks for a signal or custom message:
// Custom signal
// Arguments are `signal, exitCode` (SIGBREAK is already handled, this is an example)
exitHook.hookEvent('SIGBREAK', 21);
// process event: `message` with a filter
// filter gets all arguments passed to *handler*: `process.on(message, *handler*)`
// Exits on process event `message` with msg `customShutdownMessage` only
exitHook.hookEvent('message', 0, msg => msg !== 'customShutdownMessage');
// All async hooks will work with uncaught errors when you have specified an uncaughtExceptionHandler
throw new Error('awesome');
//=> // Sync uncaughtExcpetion hooks called and retun
//=> '[Error: awesome]'
//=> // Sync hooks called and retun
//=> 'exiting'
//=> 'exiting 2'
//=> // Async uncaughtException hooks return
//=> 'Sent error to cloud'
//=> // Sync uncaughtException hooks return
//=> 'exiting 3'
```
## License
MIT © Tapani Moilanen
MIT © [Sindre Sorhus](http://sindresorhus.com)