Use DynamoDB for Data Persistence with Your Alexa-hosted Skill

Note: Sign in to the developer console to build or publish your skill.

When you create an Alexa-hosted skill, Alexa stores your code and resources on AWS for you. For an overview of hosted skills, see About Alexa-hosted Skills.

When you create an Alexa-hosted skill, you get access to an Amazon DynamoDB table for persisting data. Your DynamoDB table is part of the AWS free tier that provides storage free of charge within the usage limits. All user data stored in your DynamoDB table is fully encrypted at rest with encryption keys managed by AWS Key Management Service (KMS). For details, see DynamoDB Encryption at Rest.

The ASK SDK for Node.js and the ASK SDK for Python each include an adapter to persist data to DynamoDB.

Important: If you already use S3 for data persistence, Amazon recommends that you update your skill to use DynamoDB for data persistence instead.

View your Amazon DynamoDB table

Each Alexa-hosted skill gets one DynamoDB table for persisting data.

To see the Amazon DynamoDB table for your Alexa-hosted skill

Open the Alexa developer console and log in.
In the list of your skills, click the name of the skill that you want to view.
Click the Code tab.
In the toolbar, click the Database icon to open the AWS DynamoDB console.
Your Amazon DynamoDB table appears.

Persist data with Node.js

To persist data with Node.js

First add the following dependency in the dependencies section of your package.json file:

"ask-sdk": "^2.6.0"
"aws-sdk": "2.637.0"
"ask-sdk-dynamodb-persistence-adapter": "^2.9.0"

Then, in your index.js file, add the code. Import the ask persistence adapter.

const AWS = require("aws-sdk");
const ddbAdapter = require('ask-sdk-dynamodb-persistence-adapter');

Add the SessionEndedRequestHandler request handler to your skill builder request handlers. Don't overwrite other request handlers.

exports.handler = Alexa.SkillBuilders.custom()
    .addRequestHandlers(
        LaunchRequestHandler,
        //other request handlers,
        SessionEndedRequestHandler
    )
    .addErrorHandlers(ErrorHandler)
    .withPersistenceAdapter(
        new ddbAdapter.DynamoDbPersistenceAdapter({
            tableName: process.env.DYNAMODB_PERSISTENCE_TABLE_NAME,
            createTable: false,
            dynamoDBClient: new AWS.DynamoDB({apiVersion: 'latest', region: process.env.DYNAMODB_PERSISTENCE_REGION})
        })
    )
    .lambda();

Add a handler to save attributes.

async handle(handlerInput)
{
    const attributesManager = handlerInput.attributesManager;
    let attributes = {"counter":10};

    attributesManager.setPersistentAttributes(attributes);
    await attributesManager.savePersistentAttributes();

    let speechOutput = `Hi there, Hello World! Your saved counter is ${attributes.counter}`;

    return handlerInput.responseBuilder
        .speak(speechOutput)
        .getResponse();
}

Add a handler to read attributes.

async handle(handlerInput){

    const attributesManager = handlerInput.attributesManager;
    const attributes = await attributesManager.getPersistentAttributes() || {};
    console.log('attributes is: ', attributes);

    const counter = attributes.hasOwnProperty('counter')? attributes.counter : 0;

    let speechOutput = `Hi there, Hello World! Your counter is ${counter}`;

    return handlerInput.responseBuilder
        .speak(speechOutput)
        .getResponse();
}

Persist data with Python

To persist data with Python

First add the following dependency in the dependencies section of your requirements.txt file:
```
boto3==1.9.216
ask-sdk-core==1.11.0
ask-sdk-dynamodb-persistence-adapter==1.15.0
```

Then, in your lambda_function.py file, add the code. Import the ask persistence adapter.

import os
import boto3

from ask_sdk_core.skill_builder import CustomSkillBuilder
from ask_sdk_dynamodb.adapter import DynamoDbAdapter

Initialize the persistence adapter.

ddb_region = os.environ.get('DYNAMODB_PERSISTENCE_REGION')
ddb_table_name = os.environ.get('DYNAMODB_PERSISTENCE_TABLE_NAME')

ddb_resource = boto3.resource('dynamodb', region_name=ddb_region)
dynamodb_adapter = DynamoDbAdapter(table_name=ddb_table_name, create_table=False, dynamodb_resource=ddb_resource)