Add Chatbot Example

.tools/run_node_tests.sh

@@ -25,3 +25,4 @@ npm_install_check $PROJECT_ROOT/patterns-use-cases/ticket-reservation/ticket-res
 
 npm_install_check $PROJECT_ROOT/end-to-end-applications/typescript/ai-image-workflows
 npm_install_check $PROJECT_ROOT/end-to-end-applications/typescript/food-ordering/app
+npm_install_check $PROJECT_ROOT/end-to-end-applications/typescript/chat-bot

.tools/update_node_examples.sh

@@ -39,3 +39,4 @@ bump_ts_sdk $PROJECT_ROOT/patterns-use-cases/ticket-reservation/ticket-reservati
 bump_ts_sdk $PROJECT_ROOT/end-to-end-applications/typescript/ai-image-workflows
 bump_ts_sdk $PROJECT_ROOT/end-to-end-applications/typescript/food-ordering/app
 bump_ts_sdk_clients $PROJECT_ROOT/end-to-end-applications/typescript/food-ordering/webui
+bump_ts_sdk $PROJECT_ROOT/end-to-end-applications/typescript/chat-bot

README.md

@@ -39,6 +39,7 @@ challenges.
 | Use Cases  | [Async Tasks - Payments](patterns-use-cases/async-signals-payment/async-signals-payment-typescript/) |
 | End-to-End | [Food Ordering App](end-to-end-applications/typescript/food-ordering)                                |
 | End-to-End | [AI Image Processing Workflow](end-to-end-applications/typescript/ai-image-workflows)                |
+| End-to-End | [LLM-powered Chat Bot / Task Agent](end-to-end-applications/typescript/chat-bot)                     |
 | Tutorial   | [Tour of Restate](tutorials/tour-of-restate-typescript)                                              |
 | Templates  | [Restate Node/TS Template](templates/typescript)                                                     |
 | Templates  | [Restate Bun/TS Template](templates/bun)                                                             |

end-to-end-applications/typescript/README.md

@@ -17,3 +17,15 @@ relaying the calls to services implementing the steps.
 
 The example shows how to build a dynamic workflow interpreter and use workflows to drive work in
 other services.
+
+
+### Chatbot - LLM / Agents
+
+The [Chat Bot](chat-bot) example implements an LLM-powered chat bot with Slack integration that can be asked to
+handle tasks, like watching flight prices, or sending reminders.
+
+It illustrates how to
+* Use restate for stateful LLM interactions (state holds the chat history and active tasks)
+* Create and interact the async tasks running the respective activities
+
+

end-to-end-applications/typescript/chat-bot/README.md

@@ -0,0 +1,79 @@
+
+# The Chatbot
+
+This example is a chatbot for slack that interfaces with am LLM (GPT-4o) and maintains various tasks,
+like reminders or watching flight prices. The video below (click the image) has a nice intro to the functionality and architecture.
+
+<a href="http://www.youtube.com/watch?feature=player_embedded&v=qsmoHmNUXNg" target="_blank">
+ <img src="http://img.youtube.com/vi/qsmoHmNUXNg/mqdefault.jpg" alt="Watch the video" width="240" height="180" border="10" />
+</a>
+
+## Browing the example
+
+The core chatbot logic is in [chat.ts](./src/chat.ts). This uses Restate's Virtual Objects to
+have a chat session per user, with history and active tasks easily maintained in the object state.
+
+The workflow-as-code execution of handlers ensures strict consistency and the single-writer semantics
+eforce a consistent message history even under concurrent messages or task notifications.
+
+The tasks are simple Restate workflows. See the [flight watch task](./src/tasks/flight_prices.ts) as an example. 
+
+Finally, the [slack integration](./src/slackbot.ts) handles slack webhooks, API calls,
+verification, deduplication, tracking message timestamps, etc.
+
+
+## Running the ChatBot
+
+You need an [OpenAI]() access key to access GPT-4o. Export it as an environment variable like `export OPENAI_API_KEY=sk-proj-...`
+
+Start the Restate Server (see ["Get Restate"](https://restate.dev/get-restate/) if you don't have it downloaded, yet.)
+
+Make sure you install the dependencies via `npm install`.
+
+Start the *reminder* and *flight-watch* tasks via `npm run reminder-task` and `npm run flights-task` respectively
+(e.g., in different shells). In this example, we run them as separate endpoints. Since they are mostly suspending,
+they would be prime candidates to be deployed on a FaaS platform.
+
+Let Restate know about your task services via
+```shell
+restate dep add -y localhost:9081
+restate dep add -y localhost:9082
+```
+
+### Option (1) Without Slack
+
+Start the main chatbot service via `npm run app` and register it at Restate Server `restate dep add -y localhost:9080`.
+
+To chat with the bot, make calls to the chatbot service, like
+```
+curl localhost:8080/chatSession/<session-name>/chatMessage --json '"Hey, I am Malik, what tasks can you do?"'
+curl localhost:8080/chatSession/<session-name>/chatMessage --json '"Create a reminder for in 30 minutes to get a coffee."'
+```
+
+The `<session-name>` path identifies the session - each one separately maintains its tasks and history.
+
+Async notifications from tasks (like that a cheap flight was found) come in the chat bot's log, which is a bit hidden,
+but a result of the fact that this was initially written to be used with a chat app like Slack.
+
+### Option (2): As a Slack Bot
+
+The chat bot can also be used as a [Slack](https://slack.com/) bot, as shown in the video.
+Each slack channel that the bot participates in and each direct message user are separate chat sessions.
+
+The setup is a bit more involved, because you need to create a Slack App as the connection between Slack and
+the bot. [This tutorial](https://slack.com/help/articles/13345326945043-Build-apps-with-Slacks-developer-tools)
+is a starting point.
+
+For those with some experience in building slack apps, the requirements for this bot are:
+* The following *Bot Token OAuth Scopes*: `channels:history`, `chat:write`, `groups:history`, `im:history`, `im:read`, `im:write`, `mpim:history`
+* Event subscription for the following *Bot Events*: `message.channels`, `message.groups`, `message.im`, `message.mpim`. 
+
+After installing the app to your workspace, export the following tokens and IDs as environment variables:
+```shell
+export SLACK_BOT_USER_ID=U...
+export SLACK_BOT_TOKEN=xoxb-...
+export SLACK_SIGNING_SECRET=...
+```
+
+Once all keys are set up, start the app together with the slack adapter: `npm run app -- SLACK`.
+Use a publicly reachable Restate server URL as Slack's event Request URL: `https://my-restate-uri:8080/slackbot/message`

end-to-end-applications/typescript/chat-bot/package.json

@@ -0,0 +1,23 @@
+{
+  "name": "restate-announcement-demo-chatbot",
+  "version": "1.0.0",
+  "description": "ChatBot demo for the Restate 1.0 announcement",
+  "main": "app.js",
+  "type": "commonjs",
+  "scripts": {
+    "build": "tsc --noEmitOnError",
+    "app": "ts-node-dev --watch ./src --transpile-only ./src/app.ts",
+    "reminder-task": "RESTATE_LOGGING=INFO ts-node-dev --watch ./src --transpile-only ./src/tasks/reminder.ts",
+    "flights-task": "RESTATE_LOGGING=INFO ts-node-dev --watch ./src --transpile-only ./src/tasks/flight_prices.ts"
+  },
+  "dependencies": {
+    "@restatedev/restate-sdk": "1.1.0",
+    "@slack/bolt": "^3.19.0",
+    "@slack/web-api": "^7.0.4"
+  },
+  "devDependencies": {
+    "@types/node": "^20.12.7",
+    "ts-node-dev": "^1.1.8",
+    "typescript": "^5.0.2"
+  }
+}

end-to-end-applications/typescript/chat-bot/src/app.ts

@@ -0,0 +1,31 @@
+import * as restate from "@restatedev/restate-sdk"
+import * as tm from "./taskmanager" 
+import * as slackbot from "./slackbot"
+import * as chat from "./chat"
+
+import { reminderTaskDefinition } from "./tasks/reminder";
+import { flightPricesTaskDefinition } from "./tasks/flight_prices";
+
+const mode = process.argv[2];
+
+// (1) register the task types we have at the task manager
+//     so that the task manager knows where to send certain commands to
+
+tm.registerTaskWorkflow(reminderTaskDefinition);
+tm.registerTaskWorkflow(flightPricesTaskDefinition)
+
+// (2) build the endpoint with the core handlers for the chat
+
+const endpoint = restate.endpoint()
+    .bind(chat.chatSessionService)
+    .bind(tm.workflowInvoker)
+
+// (3) add slackbot, if in slack mode
+
+if (mode === "SLACK") {
+    endpoint.bindBundle(slackbot.services)
+    chat.notificationHandler(slackbot.notificationHandler)
+}
+
+// start the defaut http2 server (alternatively export as lambda handler, http handler, ...)
+endpoint.listen(9080);