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# tiny-worker
Tiny WebWorker for Server
`require()` is available for flexible inline Worker scripts. Optional parameters `args` Array & `options` Object; see `child_process.fork()` documentation.
[](http://travis-ci.org/avoidwork/tiny-worker)
## Example
#### Creating a Worker from a file
The worker script:
```javascript
onmessage = function (ev) {
postMessage(ev.data);
};
```
The core script:
```javascript
var Worker = require("tiny-worker");
var worker = new Worker("repeat.js");
worker.onmessage = function (ev) {
console.log(ev.data);
worker.terminate();
};
worker.postMessage("Hello World!");
```
#### Creating a Worker from a Function
```javascript
var Worker = require("tiny-worker");
var worker = new Worker(function () {
self.onmessage = function (ev) {
postMessage(ev.data);
};
});
worker.onmessage = function (ev) {
console.log(ev.data);
worker.terminate();
};
worker.postMessage("Hello World!");
```
# Debugging
To be able to debug a child process, it must have a differnt debug port than the parent.
Tiny worker does this by adding a random port within a range to the parents debug port.
The default Range is `[1, 300]`, it can be changed with the `setRange(min, max)` method.
To disable any automatic port redirection set `options.noDebugRedirection = true`.
### automatic redirection
```javascript
//parent is started with '--debug=1234'
var Worker = require("tiny-worker");
Worker.setRange(2, 20);
var worker = new Worker(function () {
postMessage(process.debugPort);
});
worker.onmessage = function (ev) {
console.log(ev.data); //prints any number between 1236 and 1254
worker.terminate();
}
```
### manual redirection
```javascript
//parent is started with '--debug=1234'
var Worker = require("tiny-worker");
var worker = new Worker(function () {
postMessage(process.debugPort);
}, [], {noDebugRedirection: true, execArgv: ["--debug=1235"]});
worker.onmessage = function (ev) {
console.log(ev.data); //prints 1235
worker.terminate();
}
```
## Properties
#### onmessage
Message handler, accepts an `Event`
#### onerror
Error handler, accepts an `Event`
## API
#### addEventListener(event, fn)
Adds an event listener
#### postMessage()
Broadcasts a message to the `Worker`
#### terminate()
Terminates the `Worker`
#### static setRange(min, max)
Sets range for debug ports, only affects current process.
Returns true if successful.
## FAQ
1. I have an orphaned child process that lives on past the parent process' lifespan
* Most likely a `SIGTERM` or `SIGINT` is not reaching the child process
2. How do I insure all process are terminated?
* In your core script register a listener for `SIGTERM` or `SIGINT` via `process.on()` which terminates (all) worker process(es) and then gracefully shutdowns via `process.exit(0);`
3. Why `SIGTERM` or `SIGINT`?
* Unix/BSD will work with `SIGTERM`, but if you also need to support Windows use `SIGINT`
## License
Copyright (c) 2017 Jason Mulligan
Licensed under the BSD-3 license
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