Make Handler API more concise for ticket reservation app

restatedev · Feb 1, 2024 · 7d4e879 · 7d4e879
1 parent 1cd4f30
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diff --git a/typescript/ticket-reservation/README.md b/typescript/ticket-reservation/README.md
@@ -81,26 +81,11 @@ Here is an incomplete list of simplifications to the application that are possib
 - Latest stable version of [NodeJS](https://nodejs.org/en/) >= v18.17.1 and [npm CLI](https://docs.npmjs.com/downloading-and-installing-node-js-and-npm) >= 9.6.7 installed.
 - [Docker Engine](https://docs.docker.com/engine/install/) to launch the Restate runtime (not needed for the app implementation itself).
 
-### Setup
-
-Clone this GitHub repository and navigate to the `ticket-reservation` folder:
-
-```shell
-git clone [email protected]:restatedev/examples.git
-cd ticket-reservation
-```
-
-Next, install the dependencies:
+### Run the example
+Install the dependencies, build the app and run it:
 
 ```shell
 npm install
-```
-
-### Run the service
-
-Once you are done with the implementation, build/run the example app with:
-
-```shell
 npm run build
 npm run app
 ```

diff --git a/typescript/ticket-reservation/src/checkout.ts b/typescript/ticket-reservation/src/checkout.ts
@@ -14,40 +14,39 @@ import { v4 as uuid } from "uuid";
 import { StripeClient } from "./auxiliary/stripe_client";
 import { EmailClient } from "./auxiliary/email_client";
 
-const doCheckout = async (
-  ctx: restate.RpcContext,
-  request: { userId: string; tickets: string[] }
-) => {
-  // We are a uniform shop where everything costs 40 USD
-  const totalPrice = request.tickets.length * 40;
-
-  // Generate idempotency key for the stripe client
-  const idempotencyKey = await ctx.sideEffect(async () => uuid());
-  const stripe = StripeClient.get();
-
-  const doPayment = async () => stripe.call(idempotencyKey, totalPrice);
-  const success = await ctx.sideEffect(doPayment);
-
-  const email = EmailClient.get();
-
-  if (success) {
-    console.info("Payment successful. Notifying user about shipment.");
-    await ctx.sideEffect(async () =>
-      email.notifyUserOfPaymentSuccess(request.userId)
-    );
-  } else {
-    console.info("Payment failure. Notifying user about it.");
-    await ctx.sideEffect(async () =>
-      email.notifyUserOfPaymentFailure(request.userId)
-    );
+export const checkoutRouter = restate.router({
+  checkout: async (
+      ctx: restate.RpcContext,
+      request: { userId: string; tickets: string[] }
+  ) => {
+    // We are a uniform shop where everything costs 40 USD
+    const totalPrice = request.tickets.length * 40;
+
+    // Generate idempotency key for the stripe client
+    const idempotencyKey = await ctx.sideEffect(async () => uuid());
+    const stripe = StripeClient.get();
+
+    const doPayment = async () => stripe.call(idempotencyKey, totalPrice);
+    const success = await ctx.sideEffect(doPayment);
+
+    const email = EmailClient.get();
+
+    if (success) {
+      console.info("Payment successful. Notifying user about shipment.");
+      await ctx.sideEffect(async () =>
+          email.notifyUserOfPaymentSuccess(request.userId)
+      );
+    } else {
+      console.info("Payment failure. Notifying user about it.");
+      await ctx.sideEffect(async () =>
+          email.notifyUserOfPaymentFailure(request.userId)
+      );
+    }
+
+    return success;
   }
-
-  return success;
-};
+});
 
 export const checkoutApi: restate.ServiceApi<typeof checkoutRouter> = {
   path: "CheckoutProcess",
-};
-export const checkoutRouter = restate.router({
-  checkout: doCheckout,
-});
+};
diff --git a/typescript/ticket-reservation/src/ticket_db.ts b/typescript/ticket-reservation/src/ticket_db.ts
@@ -17,47 +17,43 @@ enum TicketStatus {
   Sold,
 }
 
-const doReserveTicket = async (ctx: restate.RpcContext) => {
-  const status =
-    (await ctx.get<TicketStatus>("status")) ?? TicketStatus.Available;
-
-  if (status === TicketStatus.Available) {
-    ctx.set("status", TicketStatus.Reserved);
-    return true;
-  } else {
-    return false;
-  }
-};
-
-const doUnreserveTicket = async (ctx: restate.RpcContext) => {
-  const status =
-    (await ctx.get<TicketStatus>("status")) ?? TicketStatus.Available;
-
-  if (status === TicketStatus.Sold) {
-    return false;
-  } else {
-    ctx.clear("status");
-    return true;
-  }
-};
-
-const doMarkAsSold = async (ctx: restate.RpcContext) => {
-  const status =
-    (await ctx.get<TicketStatus>("status")) ?? TicketStatus.Available;
+export const ticketDbRouter = restate.keyedRouter({
+  reserve: async (ctx: restate.RpcContext) => {
+    const status =
+        (await ctx.get<TicketStatus>("status")) ?? TicketStatus.Available;
+
+    if (status === TicketStatus.Available) {
+      ctx.set("status", TicketStatus.Reserved);
+      return true;
+    } else {
+      return false;
+    }
+  },
+  unreserve: async (ctx: restate.RpcContext) => {
+    const status =
+        (await ctx.get<TicketStatus>("status")) ?? TicketStatus.Available;
+
+    if (status === TicketStatus.Sold) {
+      return false;
+    } else {
+      ctx.clear("status");
+      return true;
+    }
+  },
+  markAsSold: async (ctx: restate.RpcContext) => {
+    const status =
+        (await ctx.get<TicketStatus>("status")) ?? TicketStatus.Available;
+
+    if (status === TicketStatus.Reserved) {
+      ctx.set("status", TicketStatus.Sold);
+      return true;
+    } else {
+      return false;
+    }
+  },
+});
 
-  if (status === TicketStatus.Reserved) {
-    ctx.set("status", TicketStatus.Sold);
-    return true;
-  } else {
-    return false;
-  }
-};
 
 export const ticketDbApi: restate.ServiceApi<typeof ticketDbRouter> = {
   path: "TicketDb",
 };
-export const ticketDbRouter = restate.keyedRouter({
-  reserve: doReserveTicket,
-  unreserve: doUnreserveTicket,
-  markAsSold: doMarkAsSold,
-});
diff --git a/typescript/ticket-reservation/src/user_session.ts b/typescript/ticket-reservation/src/user_session.ts
@@ -13,76 +13,71 @@ import * as restate from "@restatedev/restate-sdk";
 import { ticketDbApi } from "./ticket_db";
 import { checkoutApi } from "./checkout";
 
-const doAddTicket = async (
-  ctx: restate.RpcContext,
-  userId: string,
-  ticketId: string
-) => {
-  // try to reserve ticket
-  const reservation_response = await ctx.rpc(ticketDbApi).reserve(ticketId);
-
-  if (reservation_response) {
-    // add ticket to user session items
-    const tickets = (await ctx.get<string[]>("items")) ?? [];
-    tickets.push(ticketId);
-    ctx.set("items", tickets);
-
-    // Schedule expiry timer
-    ctx
-      .sendDelayed(userSessionApi, 15 * 60 * 1000)
-      .expireTicket(userId, ticketId);
-  }
-
-  return reservation_response;
-};
+export const userSessionRouter = restate.keyedRouter({
+  addTicket: async (
+      ctx: restate.RpcContext,
+      userId: string,
+      ticketId: string
+  ) => {
+    // try to reserve ticket
+    const reservation_response = await ctx.rpc(ticketDbApi).reserve(ticketId);
 
-const doExpireTicket = async (
-  ctx: restate.RpcContext,
-  userId: string,
-  ticketId: string
-) => {
-  ctx.send(ticketDbApi).unreserve(ticketId);
-  const tickets = (await ctx.get<string[]>("items")) ?? [];
+    if (reservation_response) {
+      // add ticket to user session items
+      const tickets = (await ctx.get<string[]>("items")) ?? [];
+      tickets.push(ticketId);
+      ctx.set("items", tickets);
 
-  const index = tickets.findIndex((id) => id === ticketId);
+      // Schedule expiry timer
+      ctx
+          .sendDelayed(userSessionApi, 15 * 60 * 1000)
+          .expireTicket(userId, ticketId);
+    }
 
-  // try removing ticket
-  if (index != -1) {
-    tickets.splice(index, 1);
-    ctx.set("items", tickets);
-    // unreserve if ticket was reserved before
+    return reservation_response;
+  },
+  expireTicket: async (
+      ctx: restate.RpcContext,
+      userId: string,
+      ticketId: string
+  ) => {
     ctx.send(ticketDbApi).unreserve(ticketId);
-  }
-};
+    const tickets = (await ctx.get<string[]>("items")) ?? [];
 
-const doCheckout = async (ctx: restate.RpcContext, userId: string) => {
-  const tickets = await ctx.get<string[]>("items");
+    const index = tickets.findIndex((id) => id === ticketId);
 
-  if (tickets && tickets.length > 0) {
-    const checkout_success = await ctx
-      .rpc(checkoutApi)
-      .checkout({ userId: userId, tickets: tickets! });
+    // try removing ticket
+    if (index != -1) {
+      tickets.splice(index, 1);
+      ctx.set("items", tickets);
+      // unreserve if ticket was reserved before
+      ctx.send(ticketDbApi).unreserve(ticketId);
+    }
+  },
+  checkout: async (ctx: restate.RpcContext, userId: string) => {
+    const tickets = await ctx.get<string[]>("items");
+
+    if (tickets && tickets.length > 0) {
+      const checkout_success = await ctx
+          .rpc(checkoutApi)
+          .checkout({ userId: userId, tickets: tickets! });
 
-    if (checkout_success) {
-      // mark items as sold if checkout was successful
-      for (const ticket_id of tickets) {
-        ctx.send(ticketDbApi).markAsSold(ticket_id);
+      if (checkout_success) {
+        // mark items as sold if checkout was successful
+        for (const ticket_id of tickets) {
+          ctx.send(ticketDbApi).markAsSold(ticket_id);
+        }
+        ctx.clear("items");
       }
-      ctx.clear("items");
-    }
 
-    return checkout_success;
-  } else {
-    // no tickets reserved
-    return false;
-  }
-};
+      return checkout_success;
+    } else {
+      // no tickets reserved
+      return false;
+    }
+  },
+});
 
 export const userSessionApi: restate.ServiceApi<typeof userSessionRouter> = {
   path: "UserSession",
 };
-export const userSessionRouter = restate.keyedRouter({
-  addTicket: doAddTicket,
-  expireTicket: doExpireTicket,
-  checkout: doCheckout,
-});