A simple command-line tool to start NetBSD virtual machines using QEMU with sensible defaults.
tsiry-sandratraina.com
Refactor subcommands to use Effect for error handling and asynchronous operations
1import { Data, Effect, pipe } from "effect";
2import type { VirtualMachine } from "../db.ts";
3import { getInstanceState, removeInstanceState } from "../state.ts";
4
5class VmNotFoundError extends Data.TaggedError("VmNotFoundError")<{
6 name: string;
7}> {}
8
9const findVm = (name: string) =>
10 pipe(
11 getInstanceState(name),
12 Effect.flatMap((vm) =>
13 vm ? Effect.succeed(vm) : Effect.fail(new VmNotFoundError({ name }))
14 ),
15 );
16
17const logRemoving = (vm: VirtualMachine) =>
18 Effect.sync(() => {
19 console.log(`Removing virtual machine ${vm.name} (ID: ${vm.id})...`);
20 });
21
22const removeVm = (name: string, vm: VirtualMachine) =>
23 pipe(
24 removeInstanceState(name),
25 Effect.map(() => vm),
26 );
27
28const handleError = (error: VmNotFoundError | Error) =>
29 Effect.sync(() => {
30 if (error instanceof VmNotFoundError) {
31 console.error(
32 `Virtual machine with name or ID ${error.name} not found.`,
33 );
34 } else {
35 console.error(`An error occurred: ${error}`);
36 }
37 Deno.exit(1);
38 });
39
40const removeEffect = (name: string) =>
41 pipe(
42 findVm(name),
43 Effect.tap(logRemoving),
44 Effect.flatMap((vm) => removeVm(name, vm)),
45 Effect.catchAll(handleError),
46 );
47
48export default async function (name: string) {
49 await Effect.runPromise(removeEffect(name));
50}