melienherrera / getting-started-with-astra-java

Example REST API in Java showing how to connect to and query DataStax Astra databases

Getting Started with Apache Cassandra™ and Java using DataStax Astra DB

50 minutes, Intermediate, Start Building

This provides an example REST backend built in Java using Spring Boot for use with the Getting Started with Astra UI.

Objectives

• How to connect to Astra DB via the Secure Connect Bundle
• How to manage a Cassandra Session within a JAVA web application

How this Works

This is an example of a Spring Boot Microservice for use with the Astra Getting Started UI which is found here.

Get Started

To build and play with this app, follow the build instructions that are located here: https://github.com/DataStax-Examples/getting-started-with-astra-java

Prerequisites

Let's do some initial setup by creating a serverless(!) database.

DataStax Astra

1. Create a DataStax Astra account if you don't already have one:

2. On the home page. Locate the button Create Database

3. Locate the Get Started button to continue

4. Define a database name, keyspace name and select a database region, then click create database.

5. Your Astra DB will be ready when the status will change from Pending to Active 💥💥💥

6. After your database is provisioned, we need to generate an Application Token for our App. Go to the Settings tab in the database home screen.

7. Select Admin User for the role for this Sample App and then generate the token. Download the CSV so that we can use the credentials we need later.

8. After you have your Application Token, head to the database connect screen and select the driver connection that we need. Go ahead and download the Secure Bundle for the driver.

9. Make note of where to use the Client Id and Client Secret that is part of the Application Token that we generated earlier.

Github

1. Click Use this template at the top of the GitHub Repository:

2. Enter a repository name and click 'Create repository from template':

3. Clone the repository:

🚀 Getting Started Paths:

Make sure you've completed the prerequisites before starting this step

• Running on your local machine

Running on your local machine

Make sure that you have:

• Java 11+
• An Astra DB compatible Java driver, instructions may be found here to install this locally.
• An Astra database with the CQL schema located in schema.cql already added.
• The username, password, keyspace name, and secure connect bundle downloaded from your Astra DB. For information on how to obtain these credentials please read the documentation found here.

This application is a Spring Boot web application. This sample can be run from the root directory using:

cd getting-started-with-astra-java

mvn spring-boot:run

This will startup the application running on http://localhost:8080

You will know that you are up and working when you get the following in your terminal window:

16:23:01.569 INFO  com.datastax.astra.GettingStartedWithAstra  : Started GettingStartedWithAstra in 1.851 seconds (JVM running for 2.39)

Access the API documentation from a browser

http://localhost:8080

Note: If you want to change the listening port of the application, locate the file src/main/resources/application.yml and change key server.port

Setup the user interface to use this backend

To setup the UI to connect to Java backend define a .env file in the getting-started-with-astra-ui project main directory. Inside the file it should have one entry pointing to this project's API endpoint:

BASE_ADDRESS=http://localhost:8080/api

Once you start that project with a npm run build it will point the UI to the backend API which will then be using Astra DB as a database. When you first connect to the UI, a dialog box will open asking for Astra DB connection information.