Makes healthcheck data a server polling thing.

src/lib/server/serviceDataPolling.ts

@@ -0,0 +1,65 @@
+import type { Config, ServiceConfig } from '$lib/config';
+import type { AsyncServiceHandler, ServiceData, ServiceHandler } from '$lib/services/service';
+import { getServiceHandler } from '$lib/services/services';
+import { serverConfig } from './config';
+
+export const serviceData: Array<Array<unknown>> = [];
+
+function isPromise(p: any): boolean {
+	return typeof p === 'object' && typeof p.then === 'function';
+}
+
+async function pollGeneric(upstream: ServiceData, url: string): Promise<ServiceData> {
+	upstream.status = undefined;
+	return fetch(url).then((resp: Response): ServiceData => {
+		upstream.status = resp.ok ? 'online' : 'offline';
+		return upstream;
+	});
+}
+
+function wrapHandler(handler: ServiceHandler): AsyncServiceHandler {
+	return async (config: ServiceConfig): Promise<ServiceData> => {
+		const value = handler(config);
+		if (isPromise(value) === true) {
+			return (value as Promise<ServiceData>).then((data: ServiceData) => {
+				if (data.status != undefined) {
+					return data;
+				}
+				return pollGeneric(data, config.url);
+			});
+		}
+		return pollGeneric(value as ServiceData, config.url);
+	};
+}
+
+function pollServices() {
+	const config: Config = serverConfig();
+
+	for (const [i, group] of config.services.entries()) {
+		for (const [j, service] of group.items.entries()) {
+			const handler: ServiceHandler =
+				getServiceHandler(service.type || '') ||
+				(() => {
+					return {} as ServiceData;
+				});
+
+			wrapHandler(handler)(service).then((data: ServiceData) => {
+				serviceData[i][j] = data;
+			});
+		}
+	}
+}
+
+export function initializeServiceData() {
+	const config = serverConfig();
+	serviceData.length = config.services.length;
+	for (let i = 0; i < serviceData.length; i++) {
+		serviceData[i] = [];
+	}
+}
+
+export function initServicePolling() {
+	initializeServiceData();
+	pollServices();
+	setInterval(pollServices, 30000);
+}