New serverless pattern - lambda-df-slack

lambda-df-slack/README.md

@@ -0,0 +1,166 @@
+# AWS Lambda Durable Functions to Slack via Bedrock AgentCore
+
+This pattern demonstrates a Slack chatbot that uses AWS Lambda Durable Functions for stateful, multi-turn conversations with human-in-the-loop interactions. The bot collects travel preferences from users via Slack, generates personalized itineraries using Amazon Bedrock (Claude) through AgentCore, and delivers results back to the user — all with automatic state persistence across invocations.
+
+Learn more about this pattern at Serverless Land Patterns: https://serverlessland.com/patterns/lambda-df-slack
+
+Important: this application uses various AWS services and there are costs associated with these services after the Free Tier usage - please see the [AWS Pricing page](https://aws.amazon.com/pricing/) for details. You are responsible for any AWS costs incurred. No warranty is implied in this example.
+
+## Requirements
+
+* [Create an AWS account](https://portal.aws.amazon.com/gp/aws/developer/registration/index.html) if you do not already have one and log in. The IAM user that you use must have sufficient permissions to make necessary AWS service calls and manage AWS resources.
+* [AWS CLI](https://docs.aws.amazon.com/cli/latest/userguide/install-cliv2.html) installed and configured
+* [Git Installed](https://git-scm.com/book/en/v2/Getting-Started-Installing-Git)
+* [Terraform](https://developer.hashicorp.com/terraform/downloads) >= 1.5.0 installed
+* [Docker](https://docs.docker.com/get-docker/) or [Finch](https://github.com/runfinch/finch) installed (for building the AgentCore agent container)
+* Amazon Bedrock access enabled for **Anthropic Claude 3.5 Sonnet v2** in us-east-2
+* A Slack workspace where you can create apps
+
+## Slack Bot Setup
+
+Follow these steps to create a Slack bot and obtain the required credentials.
+
+### Create Slack App
+
+1. Go to https://api.slack.com/apps
+2. Click **"Create New App"** → **"From scratch"**
+3. App Name: `Travel Assistant` (or your choice)
+4. Select your workspace → Click **"Create App"**
+
+### Add Bot Token Scopes
+
+1. In the left sidebar, click **"OAuth & Permissions"**
+2. Scroll to **"Scopes"** → **"Bot Token Scopes"**
+3. Add these scopes:
+   - `app_mentions:read`
+   - `channels:history`
+   - `chat:write`
+   - `chat:write.public`
+   - `im:history`
+   - `im:read`
+   - `im:write`
+   - `users:read`
+
+### Install App to Workspace
+
+1. Scroll up to **"OAuth Tokens"** → Click **"Install to Workspace"**
+2. Review permissions → Click **"Allow"**
+3. Copy the **Bot User OAuth Token** (starts with `xoxb-`)
+
+### Get Signing Secret
+
+1. Go to **"Basic Information"** in the left sidebar
+2. Under **"App Credentials"**, copy the **Signing Secret**
+
+Save both values — you'll need them during deployment.
+
+## Deployment Instructions
+
+1. Clone the repository and navigate to the project directory:
+    ```bash
+    git clone https://github.com/aws-samples/serverless-patterns
+    cd serverless-patterns/lambda-df-slack
+    cd terraform
+    ```
+
+2. Initialize and deploy:
+    ```bash
+    terraform init
+    terraform apply -auto-approve
+    ```
+   When prompted, enter:
+    - **prefix** - this will be the prefix for all resource names
+    - **slack_bot_token** - **Bot User OAuth Token** (starts with `xoxb-`)
+    - **slack_signing_secret** - **Signing Secret** copied earlier from **"App Credentials"**
+
+3. Get the API Gateway URL from the output:
+    ```bash
+    terraform output api_gateway_url
+    ```
+
+4. Configure Slack Event Subscriptions:
+    - Go to https://api.slack.com/apps → Select your app
+    - Click **"Event Subscriptions"** → Toggle **Enable Events** to ON
+    - Set **Request URL** to your API Gateway URL (e.g., `https://abc123.execute-api.us-east-2.amazonaws.com/prod/slack/events`)
+    - Wait for **"Verified ✓"**
+    - Under **"Subscribe to bot events"**, add: `app_mention`,`message.channels`,`message.im` 
+    - Click **"Save Changes"**
+    - Go to **"Install App"** → Click **"Reinstall to Workspace"** → **"Allow"**
+
+## How it works
+
+![Architecture.png]
+
+1. **Slack Handler Lambda** receives webhook events from Slack via API Gateway, verifies the request signature, deduplicates events, and starts a new Durable Function execution for new conversations.
+
+2. **Orchestrator (Durable Function)** manages the multi-turn conversation flow. It uses `wait_for_callback()` to pause execution while waiting for user responses — the Lambda is not running during the wait. When the user replies, the callback resumes the orchestrator exactly where it left off.
+
+3. **DynamoDB Callbacks Table** stores pending callback IDs mapped to execution IDs, enabling the Slack Handler to route incoming user messages back to the correct waiting orchestrator.
+
+4. **AgentCore Agent** receives the collected travel preferences, invokes Amazon Bedrock (Claude) via the Strands framework to generate a personalized itinerary, and sends the result back via a durable execution callback.
+
+5. **Slack Handler** posts the final itinerary back to the user in Slack.
+
+The key innovation is the **wait-for-callback pattern**: the orchestrator suspends (costs nothing while waiting) and automatically resumes when the user responds — enabling multi-turn conversations without managing state manually.
+
+## Testing
+
+### Find Your Bot
+
+1. Open Slack → Go to **"Apps"** in the sidebar
+2. Click **"Travel Assistant"**
+
+### Start a Conversation
+
+Send a DM to your bot:
+```
+Plan a trip for me
+```
+
+**Expected response:**
+```
+Great! I'll help you plan an amazing trip. Let me ask you a few questions...
+📍 Where would you like to go? (e.g., Japan, Paris, New York)
+```
+
+### Complete the Flow
+
+Answer the bot's questions:
+1. **Destination:** `Tokyo`
+2. **Dates:** `June 1-10`
+3. **Budget:** `$3000`
+4. **Interests:** `food`
+
+Wait for a ~2 minutes for Bedrock to generate the itinerary.
+
+### Verify via CLI
+
+```bash
+# Check Slack Handler logs
+aws logs tail /aws/lambda/<project>-<env>-slack-handler --follow --region us-east-2
+
+# Check Orchestrator logs
+aws logs tail /aws/lambda/<project>-<env>-orchestrator --follow --region us-east-2
+
+# Check DynamoDB for conversation state
+aws dynamodb scan --table-name <project>-<env>-callbacks --region us-east-2
+```
+
+## Cleanup
+
+1. Delete all created resources
+    ```bash
+    terraform destroy -auto-approve
+    ```
+
+1. During the prompts, enter all details as entered during creation.
+
+1. Confirm all created resources has been deleted
+    ```
+    terraform show
+    ```
+
+----
+Copyright 2026 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+
+SPDX-License-Identifier: MIT-0

lambda-df-slack/agentcore-agent/.dockerignore

@@ -0,0 +1,3 @@
+__pycache__
+*.pyc
+.DS_Store

lambda-df-slack/agentcore-agent/Dockerfile

@@ -0,0 +1,22 @@
+FROM python:3.13-slim
+
+WORKDIR /app
+
+# Create non-root user first
+RUN useradd -m -u 1000 bedrock_agentcore
+
+# Install dependencies as root (system-wide)
+COPY requirements.txt .
+RUN pip install --no-cache-dir -r requirements.txt
+
+# Switch to non-root user
+USER bedrock_agentcore
+
+# Expose ports for AgentCore
+EXPOSE 8080 8000
+
+# Copy application code
+COPY --chown=bedrock_agentcore:bedrock_agentcore . .
+
+# Run the agent as a module
+CMD ["python", "-m", "agent"]

lambda-df-slack/agentcore-agent/__main__.py

@@ -0,0 +1,5 @@
+"""Entry point for AgentCore agent"""
+from agent import app
+
+if __name__ == "__main__":
+    app.run()

lambda-df-slack/agentcore-agent/agent.py

@@ -0,0 +1,143 @@
+"""
+AgentCore Agent for Travel Itinerary Generation.
+Accepts prompt + callback info, processes with Bedrock, and sends result via callback.
+"""
+import os
+import json
+import logging
+import threading
+import time
+
+import boto3
+from strands import Agent
+from strands.models import BedrockModel
+from bedrock_agentcore.runtime import BedrockAgentCoreApp
+
+# Configure CloudWatch Logs
+logger = logging.getLogger(__name__)
+logging.basicConfig(
+    level=logging.INFO,
+    format='%(asctime)s - %(name)s - %(levelname)s - %(message)s'
+)
+
+# CloudWatch logging is handled by the AgentCore runtime itself
+# No need for watchtower - just use standard logging
+LAMBDA_REGION = os.environ.get("AWS_REGION", "us-east-2")
+logger.info("Agent module loaded")
+
+app = BedrockAgentCoreApp()
+
+
+def send_callback_success(callback_id: str, result: dict):
+    """Send the result back to the durable function via callback."""
+    logger.info(f"Sending callback success for {callback_id[:20]}...")
+    lambda_client = boto3.client("lambda", region_name=LAMBDA_REGION)
+    lambda_client.send_durable_execution_callback_success(
+        CallbackId=callback_id,
+        Result=json.dumps(result),
+    )
+    logger.info("Callback sent successfully")
+
+
+def send_callback_failure(callback_id: str, error: str):
+    """Send error back to the durable function."""
+    logger.error(f"Sending callback failure: {error}")
+    lambda_client = boto3.client("lambda", region_name=LAMBDA_REGION)
+    lambda_client.send_durable_execution_callback_failure(
+        CallbackId=callback_id,
+        Error={"errorMessage": error, "errorType": "AgentError"},
+    )
+
+
+def run_agent(prompt: str, model_id: str, callback_id: str, task_id: str, system_prompt: str = None):
+    """Invoke Bedrock via Strands Agent and send result back via durable callback."""
+    try:
+        logger.info(f"Starting agent with model {model_id}")
+
+        model = BedrockModel(
+            model_id=model_id,
+            max_tokens=8192,  # Increased for detailed itineraries
+            temperature=0.8,
+        )
+
+        default_system = """You are a knowledgeable travel advisor who creates detailed,
+personalized travel itineraries. Provide practical, specific recommendations with
+clear day-by-day plans. Be helpful, enthusiastic, and concise."""
+
+        agent = Agent(
+            model=model,
+            system_prompt=system_prompt or default_system,
+        )
+
+        logger.info("Invoking Bedrock model...")
+        result = agent(prompt)
+        answer = str(result)
+
+        logger.info(f"LLM completed, generated {len(answer)} characters")
+        send_callback_success(callback_id, {"itinerary": answer})
+
+    except Exception as e:
+        logger.error(f"Agent failed: {e}", exc_info=True)
+        send_callback_failure(callback_id, str(e))
+    finally:
+        app.complete_async_task(task_id)
+
+
+@app.entrypoint
+def entrypoint(payload):
+    """
+    Main entrypoint invoked by AgentCore Runtime.
+
+    Expects payload:
+      - prompt: travel planning prompt
+      - callbackId: durable execution callback ID
+      - model (optional): { modelId: "..." }
+      - systemPrompt (optional): custom system prompt
+
+    Returns confirmation immediately, then processes in background.
+    """
+    prompt = payload.get("prompt", "")
+    callback_id = payload.get("callbackId")
+    model_config = payload.get("model", {})
+    system_prompt = payload.get("systemPrompt")
+
+    model_id = model_config.get(
+        "modelId",
+        "us.anthropic.claude-sonnet-4-6"
+    )
+
+    if not callback_id:
+        logger.error("Missing callbackId in payload")
+        return {"error": "Missing callbackId in payload"}
+
+    if not prompt:
+        logger.error("Missing prompt in payload")
+        return {"error": "Missing prompt in payload"}
+
+    logger.info(f"Received request with callback {callback_id[:20]}...")
+
+    # Track the async task so /ping reports HealthyBusy
+    task_id = app.add_async_task("itinerary_generation", {
+        "prompt": prompt[:100] + "..." if len(prompt) > 100 else prompt,
+        "callbackId": callback_id[:20] + "...",
+    })
+
+    # Run the LLM work in background thread
+    threading.Thread(
+        target=run_agent,
+        args=(prompt, model_id, callback_id, task_id, system_prompt),
+        daemon=True,
+    ).start()
+
+    logger.info("Request accepted, processing in background")
+
+    # Return confirmation immediately
+    return {
+        "status": "accepted",
+        "message": "Generating itinerary, will callback when complete",
+        "callbackId": callback_id,
+    }
+
+
+if __name__ == "__main__":
+    app.run()

lambda-df-slack/agentcore-agent/requirements.txt

@@ -0,0 +1,4 @@
+strands-agents
+bedrock-agentcore
+boto3
+aws-durable-execution-sdk-python