Deploying a Node.js application with DynamoDB to Elastic Beanstalk - AWS Elastic Beanstalk
PrerequisitesCreate an Elastic Beanstalk environmentAdd permissions to your environment's instancesDeploy the example applicationCreate a DynamoDB tableUpdate the application's configuration filesConfigure your environment for high availabilityCleanupNext steps

Deploying a Node.js application with DynamoDB to Elastic Beanstalk

This tutorial and its example application nodejs-example-dynamo.zip walks you through the process of deploying a Node.js application that uses the AWS SDK for JavaScript in Node.js to interact with the Amazon DynamoDB service. You'll create a DynamoDB table that's in a database that's decoupled, or external, from the AWS Elastic Beanstalk environment. You'll also configure the application to use a decoupled database. In a production environment, it's best practice to use a database that's decoupled from the Elastic Beanstalk environment so that it's independent from the environment's life cycle. This practice also enables you to perform blue/green deployments.

The example application illustrates the following:

  • A DynamoDB table that stores user-provided text data.

  • The configuration files to create the table.

  • An Amazon Simple Notification Service topic.

  • Use of a package.json file to install packages during deployment.

Prerequisites

This tutorial requires the following prerequisites:

  • The Node.js runtimes

  • The default Node.js package manager software, npm

  • The Express command line generator

  • The Elastic Beanstalk Command Line Interface (EB CLI)

For details about installing the first three listed components and setting up your local development environment, see Setting up your Node.js development environment. For this tutorial, you don't need to install the AWS SDK for Node.js, which is also mentioned in the referenced topic.

For details about installing and configuring the EB CLI, see Install the EB CLI and Configure the EB CLI.

Create an Elastic Beanstalk environment

Your application directory

This tutorial uses a directory called nodejs-example-dynamo for the application source bundle. Create the nodejs-example-dynamo directory for this tutorial.

~$ mkdir nodejs-example-dynamo
Note

Each tutorial in this chapter uses it's own directory for the application source bundle. The directory name matches the name of the sample application used by the tutorial.

Change your current working directory to nodejs-example-dynamo.

~$ cd nodejs-example-dynamo

Now, let's set up an Elastic Beanstalk environment running the Node.js platform and the sample application. We'll use the Elastic Beanstalk command line interface (EB CLI).

To configure an EB CLI repository for your application and create an Elastic Beanstalk environment running the Node.js platform

  1. Create a repository with the eb init command.

    ~/nodejs-example-dynamo$ eb init --platform node.js --region <region>

    This command creates a configuration file in a folder named .elasticbeanstalk that specifies settings for creating environments for your application, and creates an Elastic Beanstalk application named after the current folder.

  2. Create an environment running a sample application with the eb create command.

    ~/nodejs-example-dynamo$ eb create --sample nodejs-example-dynamo

    This command creates a load-balanced environment with the default settings for the Node.js platform and the following resources:

    • EC2 instance – An Amazon Elastic Compute Cloud (Amazon EC2) virtual machine configured to run web apps on the platform that you choose.

      Each platform runs a specific set of software, configuration files, and scripts to support a specific language version, framework, web container, or combination of these. Most platforms use either Apache or NGINX as a reverse proxy that sits in front of your web app, forwards requests to it, serves static assets, and generates access and error logs.

    • Instance security group – An Amazon EC2 security group configured to allow inbound traffic on port 80. This resource lets HTTP traffic from the load balancer reach the EC2 instance running your web app. By default, traffic isn't allowed on other ports.

    • Load balancer – An Elastic Load Balancing load balancer configured to distribute requests to the instances running your application. A load balancer also eliminates the need to expose your instances directly to the internet.

    • Load balancer security group – An Amazon EC2 security group configured to allow inbound traffic on port 80. This resource lets HTTP traffic from the internet reach the load balancer. By default, traffic isn't allowed on other ports.

    • Auto Scaling group – An Auto Scaling group configured to replace an instance if it is terminated or becomes unavailable.

    • Amazon S3 bucket – A storage location for your source code, logs, and other artifacts that are created when you use Elastic Beanstalk.

    • Amazon CloudWatch alarms – Two CloudWatch alarms that monitor the load on the instances in your environment and that are triggered if the load is too high or too low. When an alarm is triggered, your Auto Scaling group scales up or down in response.

    • AWS CloudFormation stack – Elastic Beanstalk uses AWS CloudFormation to launch the resources in your environment and propagate configuration changes. The resources are defined in a template that you can view in the AWS CloudFormation console.

    • Domain name – A domain name that routes to your web app in the form subdomain.region.elasticbeanstalk.com.

  3. When environment creation completes, use the eb open command to open the environment's URL in the default browser.

    ~/nodejs-example-dynamo$ eb open

You have now created a Node.js Elastic Beanstalk environment with a sample application. You can update it with your own application. Next, we update the sample application to use the Express framework.

Add permissions to your environment's instances

Your application runs on one or more EC2 instances behind a load balancer, serving HTTP requests from the Internet. When it receives a request that requires it to use AWS services, the application uses the permissions of the instance it runs on to access those services.

The sample application uses instance permissions to write data to a DynamoDB table, and to send notifications to an Amazon SNS topic with the SDK for JavaScript in Node.js. Add the following managed policies to the default instance profile to grant the EC2 instances in your environment permission to access DynamoDB and Amazon SNS:

  • AmazonDynamoDBFullAccess

  • AmazonSNSFullAccess

To add policies to the default instance profile

  1. Open the Roles page in the IAM console.

  2. Choose aws-elasticbeanstalk-ec2-role.

  3. On the Permissions tab, choose Attach policies.

  4. Select the managed policy for the additional services that your application uses. For this tutorial, select AmazonSNSFullAccess and AmazonDynamoDBFullAccess.

  5. Choose Attach policy.

See Managing Elastic Beanstalk instance profiles for more on managing instance profiles.

Deploy the example application

Now your environment is ready for you to deploy and run the example application for this tutorial: nodejs-example-dynamo.zip .

To deploy and run the tutorial example application

  1. Change your current working directory to the application directory nodejs-example-dynamo.

    ~$ cd nodejs-example-dynamo

  2. Download the example application source bundle nodejs-example-dynamo.zip to the application directory nodejs-example-dynamo.

  3. Deploy the example application to your Elastic Beanstalk environment with the eb deploy command.

    ~/nodejs-example-dynamo$ eb deploy

  4. When environment creation completes, use the eb open command to open the environment's URL in the default browser.

    ~/nodejs-example-dynamo$ eb open

The site collects user contact information and uses a DynamoDB table to store the data. To add an entry, choose Sign up today, enter a name and email address, and then choose Sign Up!. The web app writes the form contents to the table and triggers an Amazon SNS email notification.

Right now, the Amazon SNS topic is configured with a placeholder email for notifications. You will update the configuration soon, but in the meantime you can verify the DynamoDB table and Amazon SNS topic in the AWS Management Console.

To view the table

  1. Open the Tables page in the DynamoDB console.

  2. Find the table that the application created. The name starts with awseb and contains StartupSignupsTable.

  3. Select the table, choose Items, and then choose Start search to view all items in the table.

The table contains an entry for every email address submitted on the signup site. In addition to writing to the table, the application sends a message to an Amazon SNS topic that has two subscriptions, one for email notifications to you, and another for an Amazon Simple Queue Service queue that a worker application can read from to process requests and send emails to interested customers.

To view the topic

  1. Open the Topics page in the Amazon SNS console.

  2. Find the topic that the application created. The name starts with awseb and contains NewSignupTopic.

  3. Choose the topic to view its subscriptions.

The application (app.js) defines two routes. The root path (/) returns a webpage rendered from an Embedded JavaScript (EJS) template with a form that the user fills out to register their name and email address. Submitting the form sends a POST request with the form data to the /signup route, which writes an entry to the DynamoDB table and publishes a message to the Amazon SNS topic to notify the owner of the signup.

The sample application includes configuration files that create the DynamoDB table, Amazon SNS topic, and Amazon SQS queue used by the application. This lets you create a new environment and test the functionality immediately, but has the drawback of tying the DynamoDB table to the environment. For a production environment, you should create the DynamoDB table outside of your environment to avoid losing it when you terminate the environment or update its configuration.

Create a DynamoDB table

To use an external DynamoDB table with an application running in Elastic Beanstalk, first create a table in DynamoDB. When you create a table outside of Elastic Beanstalk, it is completely independent of Elastic Beanstalk and your Elastic Beanstalk environments, and will not be terminated by Elastic Beanstalk.

Create a table with the following settings:

  • Table name – nodejs-tutorial

  • Primary key – email

  • Primary key type – String

To create a DynamoDB table

  1. Open the Tables page in the DynamoDB management console.

  2. Choose Create table.

  3. Type a Table name and Primary key.

  4. Choose the primary key type.

  5. Choose Create.

Update the application's configuration files

Update the configuration files in the application source to use the nodejs-tutorial table instead of creating a new one.

To update the example application for production use

  1. Change your current working directory to the application directory nodejs-example-dynamo.

    ~$ cd nodejs-example-dynamo

  2. Open .ebextensions/options.config and change the values of the following settings:

    • NewSignupEmail – Your email address.

    • STARTUP_SIGNUP_TABLE – nodejs-tutorial

    Example .ebextensions/options.config
    option_settings:
  aws:elasticbeanstalk:customoption:
    NewSignupEmail: you@example.com
  aws:elasticbeanstalk:application:environment:
    THEME: "flatly"
    AWS_REGION: '`{"Ref" : "AWS::Region"}`'
    STARTUP_SIGNUP_TABLE: nodejs-tutorial
    NEW_SIGNUP_TOPIC: '`{"Ref" : "NewSignupTopic"}`'
  aws:elasticbeanstalk:container:nodejs:
    ProxyServer: nginx
  aws:elasticbeanstalk:container:nodejs:staticfiles:
    /static: /static
  aws:autoscaling:asg:
    Cooldown: "120"
  aws:autoscaling:trigger:
    Unit: "Percent"
    Period: "1"
    BreachDuration: "2"
    UpperThreshold: "75"
    LowerThreshold: "30"
    MeasureName: "CPUUtilization"

    This applies the following configurations for the application:

    • The email address that the Amazon SNS topic uses for notifications is set to your address, or the one you enter in the options.config file.

    • The nodejs-tutorial table will be used instead of the one created by .ebextensions/create-dynamodb-table.config.

  3. Remove .ebextensions/create-dynamodb-table.config.

    ~/nodejs-tutorial$ rm .ebextensions/create-dynamodb-table.config

    The next time you deploy the application, the table created by this configuration file will be deleted.

  4. Deploy the updated application to your Elastic Beanstalk environment with the eb deploy command.

    ~/nodejs-example-dynamo$ eb deploy

  5. When environment creation completes, use the eb open command to open the environment's URL in the default browser.

    ~/nodejs-example-dynamo$ eb open

When you deploy, Elastic Beanstalk updates the configuration of the Amazon SNS topic and deletes the DynamoDB table that it created when you deployed the first version of the application.

Now, when you terminate the environment, the nodejs-tutorial table will not be deleted. This lets you perform blue/green deployments, modify configuration files, or take down your website without risking data loss.

Open your site in a browser and verify that the form works as you expect. Create a few entries, and then check the DynamoDB console to verify the table.

To view the table

  1. Open the Tables page in the DynamoDB console.

  2. Find the nodejs-tutorial table.

  3. Select the table, choose Items, and then choose Start search to view all items in the table.

You can also see that Elastic Beanstalk deleted the table that it created previously.

Configure your environment for high availability

Finally, configure your environment's Auto Scaling group with a higher minimum instance count. Run at least two instances at all times to prevent the web servers in your environment from being a single point of failure, and to allow you to deploy changes without taking your site out of service.

To configure your environment's Auto Scaling group for high availability

  1. Open the Elastic Beanstalk console, and in the Regions list, select your AWS Region.

  2. In the navigation pane, choose Environments, and then choose the name of your environment from the list.

    Note

    If you have many environments, use the search bar to filter the environment list.

  3. In the navigation pane, choose Configuration.

  4. In the Capacity configuration category, choose Edit.

  5. In the Auto Scaling group section, set Min instances to 2.

  6. Choose Apply at the bottom of the page.

Cleanup

When you finish working with Elastic Beanstalk, you can terminate your environment. Elastic Beanstalk terminates all AWS resources associated with your environment, such as Amazon EC2 instances, database instances, load balancers, security groups, and alarms.

To terminate your Elastic Beanstalk environment

  1. Open the Elastic Beanstalk console, and in the Regions list, select your AWS Region.

  2. In the navigation pane, choose Environments, and then choose the name of your environment from the list.

    Note

    If you have many environments, use the search bar to filter the environment list.

  3. Choose Actions, and then choose Terminate environment.

  4. Use the on-screen dialog box to confirm environment termination.

With Elastic Beanstalk, you can easily create a new environment for your application at any time.

You can also delete the external DynamoDB tables that you created.

To delete a DynamoDB table

  1. Open the Tables page in the DynamoDB console.

  2. Select a table.

  3. Choose Actions, and then choose Delete table.

  4. Choose Delete.

Next steps

The example application uses configuration files to configure software settings and create AWS resources as part of your environment. See Advanced environment customization with configuration files (.ebextensions) for more information about configuration files and their use.

The example application for this tutorial uses the Express web framework for Node.js. For more information about Express, see the official documentation at expressjs.com.

Finally, if you plan on using your application in a production environment, configure a custom domain name for your environment and enable HTTPS for secure connections.