Update sample

.scripts/list-of-samples.json

@@ -36,6 +36,7 @@
     "state",
     "timer-examples",
     "timer-progress",
+    "update",
     "vscode-debugger",
     "worker-specific-task-queues",
     "worker-versioning"

update/README.md

@@ -0,0 +1,13 @@
+### Update Sample
+
+This workflow represents a counter that can be mutated via an update called
+`fetchAndAdd`. The update adds its argument to the counter and returns the
+previous value of the counter. The update validator is used to reject negative
+arguments (rejected updates are not included in workflow history).
+
+### Running this sample
+
+1. `temporal server start-dev` to start [Temporal Server](https://github.com/temporalio/cli/#installation).
+1. `npm install` to install dependencies.
+1. `npm run start.watch` to start the Worker.
+1. In another shell, `npm run workflow` to run the Workflow Client.

update/package.json

@@ -0,0 +1,47 @@
+{
+  "name": "temporal-update",
+  "version": "0.1.0",
+  "private": true,
+  "scripts": {
+    "build": "tsc --build",
+    "build.watch": "tsc --build --watch",
+    "lint": "eslint .",
+    "start": "ts-node src/worker.ts",
+    "start.watch": "nodemon src/worker.ts",
+    "workflow": "ts-node src/client.ts",
+    "format": "prettier --config .prettierrc 'src/**/*.ts' --write",
+    "test": "mocha --exit --require ts-node/register --require source-map-support/register src/mocha/*.test.ts"
+  },
+  "nodemonConfig": {
+    "execMap": {
+      "ts": "ts-node"
+    },
+    "ext": "ts",
+    "watch": [
+      "src"
+    ]
+  },
+  "dependencies": {
+    "@temporalio/activity": "^1.9.0",
+    "@temporalio/client": "^1.9.0",
+    "@temporalio/worker": "^1.9.0",
+    "@temporalio/workflow": "^1.9.0",
+    "nanoid": "3.x"
+  },
+  "devDependencies": {
+    "@temporalio/testing": "^1.9.0",
+    "@tsconfig/node16": "^1.0.0",
+    "@types/mocha": "8.x",
+    "@types/node": "^16.11.43",
+    "@typescript-eslint/eslint-plugin": "^5.0.0",
+    "@typescript-eslint/parser": "^5.0.0",
+    "eslint": "^7.32.0",
+    "eslint-config-prettier": "^8.3.0",
+    "eslint-plugin-deprecation": "^1.2.1",
+    "mocha": "8.x",
+    "nodemon": "^2.0.12",
+    "prettier": "^2.8.8",
+    "ts-node": "^10.8.1",
+    "typescript": "^4.4.2"
+  }
+}

update/src/client.ts

@@ -0,0 +1,37 @@
+// @@@SNIPSTART typescript-update-client
+import { Connection, Client } from '@temporalio/client';
+import { counter, fetchAndAdd, done } from './workflows';
+import { nanoid } from 'nanoid';
+
+async function run() {
+  const connection = await Connection.connect({ address: 'localhost:7233' });
+  const client = new Client({ connection });
+
+  const handle = await client.workflow.start(counter, {
+    taskQueue: 'my-task-queue',
+    args: [],
+    workflowId: 'workflow-' + nanoid(),
+  });
+  console.log(`Started workflow ${handle.workflowId}`);
+
+  const prevValue = await handle.executeUpdate(fetchAndAdd, { args: [1] });
+  console.log(`incrementing counter; previous value was ${prevValue}`);
+
+  const invalidArg = -1;
+  try {
+    await handle.executeUpdate(fetchAndAdd, { args: [invalidArg] });
+  } catch (error) {
+    console.log(`Update argument ${invalidArg} was rejected: ${error}`);
+  }
+
+  // Use the signal to allow the workflow to complete.
+  await handle.signal(done);
+
+  console.log(`Final counter value is ${await handle.result()}`);
+}
+
+run().catch((err) => {
+  console.error(err);
+  process.exit(1);
+});
+// @@@SNIPEND

update/src/worker.ts

@@ -0,0 +1,21 @@
+// @@@SNIPSTART typescript-hello-worker
+import { NativeConnection, Worker } from '@temporalio/worker';
+
+async function run() {
+  const connection = await NativeConnection.connect({
+    address: 'localhost:7233',
+  });
+  const worker = await Worker.create({
+    connection,
+    namespace: 'default',
+    taskQueue: 'my-task-queue',
+    workflowsPath: require.resolve('./workflows'),
+  });
+  await worker.run();
+}
+
+run().catch((err) => {
+  console.error(err);
+  process.exit(1);
+});
+// @@@SNIPEND

update/src/workflows.ts

@@ -0,0 +1,31 @@
+// @@@SNIPSTART typescript-update-workflow
+import * as wf from '@temporalio/workflow';
+
+export const fetchAndAdd = wf.defineUpdate<number, [number]>('fetchAndAdd');
+export const done = wf.defineSignal('done');
+
+export async function counter(): Promise<number> {
+  let count = 0;
+  let shouldExit = false;
+
+  const validator = (arg: number) => {
+    if (arg < 0) {
+      throw new Error('Argument must not be negative');
+    }
+  };
+
+  const handler = (arg: number) => {
+    const prevCount = count;
+    count += arg;
+    return prevCount;
+  };
+
+  wf.setHandler(fetchAndAdd, handler, { validator });
+  wf.setHandler(done, () => {
+    shouldExit = true;
+  });
+
+  await wf.condition(() => shouldExit);
+  return count;
+}
+// @@@SNIPEND

update/tsconfig.json

@@ -0,0 +1,12 @@
+{
+  "extends": "@tsconfig/node16/tsconfig.json",
+  "version": "4.4.2",
+  "compilerOptions": {
+    "declaration": true,
+    "declarationMap": true,
+    "sourceMap": true,
+    "rootDir": "./src",
+    "outDir": "./lib"
+  },
+  "include": ["src/**/*.ts"]
+}