chore: add examples for reusing workers

Author: nyannyacha

examples/main-session/index.ts

@@ -0,0 +1,136 @@
+// @ts-ignore
+import { STATUS_CODE } from 'https://deno.land/std/http/status.ts';
+
+const SESSION_HEADER_NAME = 'X-Edge-Runtime-Session-Id';
+const WORKERS = new Map<string, EdgeRuntime.UserWorker>();
+
+setInterval(() => {
+	const shouldBeRemoved: string[] = [];
+
+	for (const [uuid, worker] of WORKERS) {
+		if (!worker.active) {
+			shouldBeRemoved.push(uuid);
+		}
+	}
+
+	for (const uuid of shouldBeRemoved) {
+		console.log("deleted: ", uuid);
+		WORKERS.delete(uuid);
+	}
+}, 2500);
+
+console.log('main function started (session mode)');
+
+Deno.serve(async (req: Request) => {
+	const headers = new Headers({
+		'Content-Type': 'application/json',
+	});
+
+	const url = new URL(req.url);
+	const { pathname } = url;
+
+	// handle health checks
+	if (pathname === '/_internal/health') {
+		return new Response(
+			JSON.stringify({ 'message': 'ok' }),
+			{
+				status: STATUS_CODE.OK,
+				headers,
+			},
+		);
+	}
+
+	if (pathname === '/_internal/metric') {
+		const metric = await EdgeRuntime.getRuntimeMetrics();
+		return Response.json(metric);
+	}
+
+	const path_parts = pathname.split('/');
+	const service_name = path_parts[1];
+
+	if (!service_name || service_name === '') {
+		const error = { msg: 'missing function name in request' };
+		return new Response(
+			JSON.stringify(error),
+			{ status: STATUS_CODE.BadRequest, headers: { 'Content-Type': 'application/json' } },
+		);
+	}
+
+	const servicePath = `./examples/${service_name}`;
+	const createWorker = async (): Promise<EdgeRuntime.UserWorker> => {
+		const memoryLimitMb = 150;
+		const workerTimeoutMs = 30 * 1000;
+		const noModuleCache = false;
+
+		const importMapPath = null;
+		const envVarsObj = Deno.env.toObject();
+		const envVars = Object.keys(envVarsObj).map((k) => [k, envVarsObj[k]]);
+		const forceCreate = false;
+		const netAccessDisabled = false;
+		const cpuTimeSoftLimitMs = 10000;
+		const cpuTimeHardLimitMs = 20000;
+
+		return await EdgeRuntime.userWorkers.create({
+			servicePath,
+			memoryLimitMb,
+			workerTimeoutMs,
+			noModuleCache,
+			importMapPath,
+			envVars,
+			forceCreate,
+			netAccessDisabled,
+			cpuTimeSoftLimitMs,
+			cpuTimeHardLimitMs,
+		});
+	};
+
+	const callWorker = async () => {
+
+		try {
+			let worker: EdgeRuntime.UserWorker | null = null;
+
+			if (req.headers.get(SESSION_HEADER_NAME)) {
+				const sessionId = req.headers.get(SESSION_HEADER_NAME)!;
+				const complexSessionId = `${servicePath}/${sessionId}`;
+
+				const maybeWorker = WORKERS.get(complexSessionId);
+
+				if (maybeWorker && maybeWorker.active) {
+					worker = maybeWorker;
+				}
+			}
+
+			if (!worker) {
+				worker = await createWorker();
+			}
+
+			const resp = await worker.fetch(req);
+
+			if (resp.headers.has(SESSION_HEADER_NAME)) {
+				const sessionIdFromWorker = resp.headers.get(SESSION_HEADER_NAME)!;
+				const complexSessionId = `${servicePath}/${sessionIdFromWorker}`;
+
+				WORKERS.set(complexSessionId, worker);
+			}
+
+			return resp;
+		} catch (e) {
+			console.error(e);
+
+			if (e instanceof Deno.errors.WorkerRequestCancelled) {
+				headers.append('Connection', 'close');
+			}
+
+			const error = { msg: e.toString() };
+			return new Response(
+				JSON.stringify(error),
+				{
+					status: STATUS_CODE.InternalServerError,
+					headers,
+				},
+			);
+		}
+	};
+
+	return callWorker();
+});

examples/serve-session/index.ts

@@ -0,0 +1,63 @@
+// @ts-ignore
+import { STATUS_CODE } from "https://deno.land/std/http/status.ts";
+
+type SessionStroage = { [key: string]: unknown };
+
+const SESSION_HEADER_NAME = "X-Edge-Runtime-Session-Id";
+const SESSIONS = new Map<string, SessionStroage>();
+
+function makeNewSession(): [string, SessionStroage] {
+    const uuid = crypto.randomUUID();
+    const storage = {};
+
+    SESSIONS.set(uuid, storage);
+    return [uuid, storage];
+}
+
+function getSessionStorageFromRequest(req: Request): SessionStroage | void {
+    const maybeSessionId = req.headers.get(SESSION_HEADER_NAME);
+
+    if (typeof maybeSessionId === "string" && SESSIONS.has(maybeSessionId)) {
+        return SESSIONS.get(maybeSessionId);
+    }
+}
+
+export default {
+    fetch(req: Request) {
+        const headers = new Headers();
+        let storage: SessionStroage;
+
+        if (req.headers.get(SESSION_HEADER_NAME)) {
+            const maybeStorage = getSessionStorageFromRequest(req);
+
+            if (!maybeStorage) {
+                return new Response(null, {
+                    status: STATUS_CODE.BadRequest
+                });
+            }
+
+            storage = maybeStorage;
+        } else {
+            const [sessionId, newStorage] = makeNewSession();
+
+            headers.set(SESSION_HEADER_NAME, sessionId);
+
+            storage = newStorage;
+        }
+
+        if (!("count" in storage)) {
+            storage["count"] = 0;
+        } else {
+            (storage["count"] as number)++;
+        }
+
+        const count = storage["count"] as number;
+
+        return new Response(
+            JSON.stringify({ count }),
+            {
+                headers
+            }
+        );
+    }
+}