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aca21dad1b
This commit makes "Worker.deno" option unstable. Added new manual entry "docs/runtime/workers.md". Removed stale workers tests.
54 lines
1.3 KiB
Markdown
54 lines
1.3 KiB
Markdown
## Workers
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Deno supports
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[`Web Worker API`](https://developer.mozilla.org/en-US/docs/Web/API/Worker/Worker).
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Workers can be used to run code on multiple threads. Each instance of `Worker`
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is run on a separate thread, dedicated only to that worker.
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Currently Deno supports only `module` type workers; thus it's essential to pass
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`type: "module"` option when creating new worker:
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```ts
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// Good
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new Worker("./worker.js", { type: "module" });
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// Bad
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new Worker("./worker.js");
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new Worker("./worker.js", { type: "classic" });
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```
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### Using Deno in worker
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**UNSTABLE**: This feature is unstable and requires `--unstable` flag
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By default `Deno` namespace is not available in worker scope.
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To add `Deno` namespace pass `deno: true` option when creating new worker:
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```ts
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// main.js
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const worker = new Worker("./worker.js", { type: "module", deno: true });
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worker.postMessage({ filename: "./log.txt" });
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// worker.js
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self.onmessage = async (e) => {
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const { filename } = e.data;
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const text = await Deno.readTextFile(filename);
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console.log(text);
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self.close();
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};
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// log.txt
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hello world
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```
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```shell
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$ deno run --allow-read --unstable main.js
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hello world
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```
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When `Deno` namespace is available in worker scope; the worker inherits parent
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process permissions (the ones specified using `--allow-*` flags).
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We intend to make permissions configurable for workers.
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