feat(cli): add graceful process abort

Using an AbortSignal and Promise.race we abandon running migrations that take longer to complete after the process is aborted than the given abortRespite period

packages/cli/src/exec.ts

@@ -1,22 +1,65 @@
-import { toError } from './errors.js';
+import prettyMs from 'pretty-ms';
+import { ExecutionDesertedError, toError } from './errors.js';
+import { DEFAULT_RESPITE_SECONDS } from './defaults.js';
 
-type Fn<Args extends any[], Result> = (...args: Args) => Result;
 type Result<T> = [value: T, error: undefined] | [value: undefined, error: Error];
 
+type ExecOptions = {
+  abortSignal?: AbortSignal;
+  abortRespite?: number;
+};
+
 /**
  * Execute a function and return a result tuple
  *
  * This is a helper function to make it easier to handle errors without the extra nesting of try/catch
+ * If an abort signal is provided the function will reject with an ExecutionDesertedError if the signal is aborted
+ * and the given function has not yet resolved within the given respite time (or a default of 30 seconds)
+ *
+ * @param fn The function to execute
+ * @param options Options for the execution
  */
-export const exec = async <Args extends any[], Return extends Promise<any>>(
-  fn: Fn<Args, Return>,
-  ...args: Args
+export const exec = async <Return extends Promise<any>>(
+  fn: () => Return,
+  options: ExecOptions = {},
 ): Promise<Result<Awaited<Return>>> => {
   try {
-    const result = await fn(...args);
+    const aborter = options.abortSignal ? getAborter(options.abortSignal, options.abortRespite) : undefined;
+    const result = await Promise.race(aborter ? [aborter, fn()] : [fn()]);
 
     return [result, undefined];
   } catch (error) {
     return [undefined, toError(error)];
   }
 };
+
+/**
+ * Returns a promise that rejects after a given time after the given signal is aborted
+ *
+ * @param signal The abort signal to listen to
+ * @param respite The time in milliseconds to wait before rejecting
+ */
+const getAborter = async (signal: AbortSignal, respite = DEFAULT_RESPITE_SECONDS * 1000): Promise<never> => {
+  return new Promise((_, reject) => {
+    if (signal.aborted) {
+      setTimeout(
+        reject,
+        respite,
+        ExecutionDesertedError.fromReason(`Deserted after ${prettyMs(respite)}`, toError(signal.reason)),
+      ).unref();
+      return;
+    }
+
+    signal.addEventListener(
+      'abort',
+      () => {
+        setTimeout(
+          reject,
+          respite,
+          ExecutionDesertedError.fromReason(`Deserted after ${prettyMs(respite)}`, toError(signal.reason)),
+        ).unref();
+      },
+      { once: true },
+    );
+  });
+};