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83 lines
1.7 KiB
Markdown
83 lines
1.7 KiB
Markdown
# Handle OS Signals
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> This program makes use of an unstable Deno feature. Learn more about
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> [unstable features](../runtime/stability.md).
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## Concepts
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- Use the `--unstable` flag to access new or unstable features in Deno.
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- [Deno.signal](https://doc.deno.land/builtin/unstable#Deno.signal) can be used
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to capture and monitor OS signals.
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- Use the `dispose()` function of the Deno.signal
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[SignalStream](https://doc.deno.land/builtin/unstable#Deno.SignalStream) to
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stop watching the signal.
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## Async iterator example
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You can use `Deno.signal()` function for handling OS signals:
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```ts
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/**
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* async-iterator-signal.ts
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*/
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console.log("Press Ctrl-C to trigger a SIGINT signal");
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for await (const _ of Deno.signal(Deno.Signal.SIGINT)) {
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console.log("interrupted!");
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Deno.exit();
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}
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```
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Run with:
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```shell
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deno run --unstable async-iterator-signal.ts
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```
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## Promise based example
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`Deno.signal()` also works as a promise:
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```ts
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/**
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* promise-signal.ts
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*/
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console.log("Press Ctrl-C to trigger a SIGINT signal");
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await Deno.signal(Deno.Signal.SIGINT);
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console.log("interrupted!");
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Deno.exit();
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```
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Run with:
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```shell
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deno run --unstable promise-signal.ts
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```
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## Stop watching signals
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If you want to stop watching the signal, you can use `dispose()` method of the
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signal object:
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```ts
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/**
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* dispose-signal.ts
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*/
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const sig = Deno.signal(Deno.Signal.SIGINT);
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setTimeout(() => {
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sig.dispose();
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console.log("No longer watching SIGINT signal");
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}, 5000);
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console.log("Watching SIGINT signals");
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for await (const _ of sig) {
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console.log("interrupted");
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}
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```
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Run with:
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```shell
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deno run --unstable dispose-signal.ts
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```
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The above for-await loop exits after 5 seconds when `sig.dispose()` is called.
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