hai

1 files changed, 49 insertions, 0 deletions

diff --git a/lib/process/signals.ts b/lib/process/signals.ts
new file mode 100644
index 0000000..c4feb7a
--- /dev/null
+++ b/lib/process/signals.ts
@@ -0,0 +1,49 @@
+import {
+    Either,
+    IEither,
+    IMetric,
+    ITraceable,
+    LogMetricTrace,
+    LogMetricTraceSupplier,
+    Mapper,
+    Metric,
+    Optional,
+    ResultMetric,
+    SideEffect,
+    TraceUtil,
+} from '@emprespresso/pengueno';
+
+export const SigIntMetric = Metric.fromName('SigInt').asResult();
+export const SigTermMetric = Metric.fromName('SigTerm').asResult();
+
+export interface Closeable<TFailure> {
+    readonly close: SideEffect<SideEffect<TFailure | undefined>>;
+}
+
+export class Signals {
+    public static async awaitClose<E extends Error>(
+        t: ITraceable<Closeable<E>, LogMetricTraceSupplier>,
+    ): Promise<IEither<Error, void>> {
+        const success: IEither<Error, void> = Either.right(<void>undefined);
+        return new Promise<IEither<Error, void>>((res) => {
+            const metricizedInterruptHandler = (metric: ResultMetric) => (err: Error | undefined) =>
+                t
+                    .flatMap(TraceUtil.withMetricTrace(metric))
+                    .peek((_t) => _t.trace.trace('closing'))
+                    .move(
+                        Optional.from(err)
+                            .map((e) => Either.left<Error, void>(e))
+                            .orSome(() => success)
+                            .get(),
+                    )
+                    .flatMap(TraceUtil.traceResultingEither(metric))
+                    .map((e) => res(e.get()))
+                    .peek((_t) => _t.trace.trace('finished'))
+                    .get();
+            const sigintCloser = metricizedInterruptHandler(SigIntMetric);
+            const sigtermCloser = metricizedInterruptHandler(SigTermMetric);
+            process.on('SIGINT', () => t.flatMap(TraceUtil.withTrace('SIGINT')).get().close(sigintCloser));
+            process.on('SIGTERM', () => t.flatMap(TraceUtil.withTrace('SIGTERM')).get().close(sigtermCloser));
+        });
+    }
+}