Manage custom state data with Azure Cosmos DB for Node.js in the v3 JavaScript SDK

Article
12/13/2017

APPLIES TO: SDK v3

In this article, you’ll implement Cosmos DB storage to store and manage your bot’s state data. The default Connector State Service used by bots is not intended for the production environment. You should either use Azure Extensions available on GitHub or implement a custom state client using data storage platform of your choice. Here are some of the reasons to use custom state storage:

higher state API throughput (more control over performance)
lower-latency for geo-distribution
control over where the data is stored (e.g.: West US vs East US)
access to the actual state data
state data db not shared with other bots
store more than 32kb

Prerequisites

Node.js.
Bot Framework Emulator
Must have a Node.js bot. If you do not have one, go create a bot.

Create Azure account

If you don't have an Azure account, click here to sign up for a free account.

Set up the Azure Cosmos DB database

After you’ve logged into the Azure portal, create a new Azure Cosmos DB database by clicking New.
Click Databases.
Find Azure Cosmos DB and click Create.
Fill in the fields. For the API field, select SQL (DocumentDB). When done filling in all the fields, click the Create button at the bottom of the screen to deploy the new database.
After the new database is deployed, navigate to your new database. Click Access keys to find keys and connection strings. Your bot will use this information to call the storage service to save state data.

Install botbuilder-azure module

To install the botbuilder-azure module from a command prompt, navigate to the bot's directory and run the following npm command:

npm install --save botbuilder-azure

Modify your bot code

To use your Azure Cosmos DB database, add the following lines of code to your bot's app.js file.

Require the newly installed module.

var azure = require('botbuilder-azure');

Configure the connection settings to connect to Azure.
```
var documentDbOptions = {
    host: 'Your-Azure-DocumentDB-URI', 
    masterKey: 'Your-Azure-DocumentDB-Key', 
    database: 'botdocs',   
    collection: 'botdata'
};
```
The host and masterKey values can be found in the Keys menu of your database. If the database and collection entries do not exist in the Azure database, they will be created for you.
Using the botbuilder-azure module, create two new objects to connect to the Azure database. First, create an instance of DocumentDBClient passing in the connection configuration settings (defined as documentDbOptions from above). Next, create an instance of AzureBotStorage passing in the DocumentDBClient object. For example:
```
var docDbClient = new azure.DocumentDbClient(documentDbOptions);

var cosmosStorage = new azure.AzureBotStorage({ gzipData: false }, docDbClient);
```

Specify that you want to use your custom database instead of the in-memory storage. For example:

var bot = new builder.UniversalBot(connector, function (session) {
     // ... Bot code ...
})
.set('storage', cosmosStorage);

Now you are ready to test the bot with the emulator.

Run your bot app

From a command prompt, navigate to your bot's directory and run your bot with the following command:

node app.js

Connect your bot to the emulator

At this point, your bot is running locally. Start the emulator and then connect to your bot from the emulator:

Type http://localhost:port-number/api/messages into the emulator's address bar, where port-number matches the port number shown in the browser where your application is running. You can leave Microsoft App ID and Microsoft App Password fields blank for now. You'll get this information later when you register your bot.
Click Connect.
Test your bot by sending your bot a message. Interact with your bot as you normally would. When you are done, go to Storage Explorer and view your saved state data.

View state data on Azure Portal

To view the state data, sign into your Azure portal and navigate to your database. Click Data Explorer (preview) to verify that the state information from your bot is being saved.

Next step

Now that you have full control over your bot's state data, let's take a look at how you can use it to better manage conversation flow.

Manage conversation flow

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