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