nozombie
Version:
track pocesses and make sure they die when they are supposed to
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Markdown
[](https://www.npmjs.com/package/nozombie)
[](https://github.com/talmobi/nozombie/blob/master/LICENSE)
# nozombie
Easy pid tracking and killing. No more zombie processes left alive!
## Easy to use
#### child_process
```javascript
const nozombie = require( 'nozombie' )
const nz = nozombie()
const spawn = childProcess.spawn( ... )
nz.add( spawn.pid ) // child will be killed when parent (process.pid) dies
```
#### puppeteer
```javascript
const nozombie = require( 'nozombie' )
const nz = nozombie()
const browser = await puppeteer.launch( opts )
const child = browser.process()
nz.add( child.pid ) // child (and descendants) ill be killed when parent (process.pid) dies
```
#### time to live
```javascript
const nozombie = require( 'nozombie' )
const nz = nozombie()
const spawn = childProcess.spawn( ... )
const FIVE_MINUTES_MS = 1000 * 60 * 5
// child will be killed when parent (process.pid) dies or 5 minutes have passed
nz.add( { pid: spawn.pid, ttl: FIVE_MINUTES_MS } )
// to update/refresh the ttl just add the same process pid again with a new ttl
nz.add( { pid: spawn.pid, ttl: FIVE_MINUTES_MS } ) // update ttl
```
#### namespace
```javascript
const nozombie = require( 'nozombie' )
const nz = nozombie()
const SCRAPE_INTERVAL = 1000 * 60 * 3
setTimeout( scapeData, 0 )
function scapeData () {
const browser = await puppeteer.launch( opts )
const child = browser.process()
const namespace = 'scrape-data'
// kill all children with this namespace
nz.kill( namespace )
// won't be killed as it was added after the kill call
nz.add( { pid: child.pid, name: namespace } )
// do something
setTimeout( scapeData, SCRAPE_INTERVAL )
}
```
## About
Track child pid's and kill them off when parent process dies.
## Why
To help keep track of pid's that need to be killed off and not leave running for too long.
## For who?
For those wanting a simple way prevent zombies.
## How
By spawning a detached, stdio ignored, unref'ed subprocess to keep track of
pids.
Once it notices that a parent pid has died, it will go into a killing
rampage of children pid's.
If all children are killed or after ~15 seconds it will suicide. Regardless if some children pid's remain alive.
Killing attempts happen about every ~1second when a children is doomed to death. A children is doomed under the following circumstances:
1. main parent process dies
2. a named parent process dies with the same name as the children
3. ttl expires
4. nz.kill() is called
5. nz.kill( name:string ) of children with that name is called
The subprocess reads the relevent pid's from a shared temporary file the main parent process creates before spawning the subprocess.
The subprocess will clean up this temporary file before it kills itself.
#### NOTE!
Killing children isn't guaranteed. When a child is doomed, it is usually killed within a few seconds.
If a child is not killed by its 10th attempt (within ~10-15 seconds), it will be considered immortal, ignored and removed silently.
## API
```javascript
const nozombie = require( 'nozombie' )
const nz = nozombie()
// spawns (or returns already existing) detached subprocess api
nz.add( pid )
// pid: number
// add pid to be killed when parent process dies
nz.add( opts )
// opts.pid: number
// opts.name: string (optional)
// opts.ttl: number (optional)
// add pid that will be killed when the ttl expires or can be manually
// killed by its name
nz.kill()
// kill all children that were added up until this point (order of add/kill matters)
nz.kill( name )
// name: string
// kill all children that match this name up until this point (order of add/kill matters)
// advanced usecase -- you probably don't need this
nozombie.spawn( { main_parent_pid: number } )
// spawn a new subprocess api and set its main_parent_pid manually
// main_parent_pid defaults to process.pid
```
## Similar
[tree-kill](https://www.npmjs.com/package/tree-kill)
[ps-list](https://www.npmjs.com/package/ps-list).
## Test
```
npm test
```