Tutorial 4 : Backend Development

Backend Development

Undertake tutorials with tech stack Spring Java backend.

tip

For completing below tutorials:

While building, Select appropriate Project configuration. And Make use of EasyManage: Templates.

Tutorial 4-A

Create Microservice

Note: Create emapi project for order table

• Create e-Commerce Order Microservice

• MySQL table:

CREATE TABLE order (
  order_id int(11) NOT NULL AUTO_INCREMENT,
  customer_id int(11) NOT NULL,
  product_id int(11) NOT NULL,
  order_date DATE NULL,
  order_quantity int(11) DEFAULT 0,
  order_status varchar(50) NULL,
  PRIMARY KEY (order_id)
);

• Customize order model with below:
  • Auto-generate orderId (order_id column)
    • Use @GeneratedValue annotation to automatically generate the primary key value for @Id.
  • Add validation for orderQuantity (order_quantity column) as below:
    • Must have value (not null) and value must be positive non-zero.
    • Min quantity: 1, Max Quantity: 5
    • Use annotations @NotNull, @Positive, @Min(1), @Max(5)

Tutorial 4-B

Microservice Communication and Events

Note: Create separate/new emapi project for shipping tables and use new ports for APIs e.g. 9060/9050

• Create e-Commerce Shipping Microservice

• MySQL tables:

CREATE TABLE product_inventory (
  product_id int(11) NOT NULL,
  available_quantity int(11) DEFAULT 0,
  PRIMARY KEY (product_id)
);

INSERT INTO product_inventory (product_id ,available_quantity)
VALUES (1,50),(2,30),(3,40);

CREATE TABLE shipping (
  shipping_id int(11) NOT NULL AUTO_INCREMENT,
  order_id int(11) NOT NULL AUTO_INCREMENT,
  product_id int(11) NOT NULL,
  shipping_quantity int(11) DEFAULT 0,
  shipping_status varchar(50) NULL,
  PRIMARY KEY (shipping_id)
);

• Then Order Microservice will communicate with Shipping Microservice for checking available product quantities before creating order.

Implement Event Distribution With kafka:

• Then Order Microservice will produce event order_created and Shipping Microservice will comsume this event and create a sihpping record.

Tutorial 4-C

Requirements for API Development

Select Project configurations for below in Builder Studio and Implement/Verify them in generated emapi project:

Testing

• tests UT Unit Tests, IT Integration Tests

• Run Tests: Report Location

• Surefire Report for unit tests

• Failsafe Report for integration tests

Code Coverage - SonarQube

Generating Code Coverage Locally with JaCoCo, Sonar Scanner

• Run Jacoco (Coverage Module)

• Report Location

• Coverage Report

• Coverage Report : dbrest

• Coverage Report : dbgraphql

• Take-home Exercises
  • Increase code coverage to 70-80%
    • Add more UT, IT
  • Migrate Integration Tests from JUnit to TestNG

tests API Tests - TestNG, WebClient

• dbrestTest - Tests Run

• dbrestTest - Report Location

• dbrestTest - Report

• dbrestTest - Emailable Report

• dbgraphqlTest - Tests Run

• dbgraphqlTest - Report

• dbgraphqlTest - Emailable Report

• Aggregate Test report

Tutorial 4-D

Enterprise Requirements for APIs and Microservices

• Take-home Exercises : Implement Enterprise Requirements for below.

Security - OAuth2 with Keycloak

Redis cache

Logging - ELK stack

Integrating - Kafka, Kafka Streams

• Distributed Events Aggregation with Kafka Streams

DevOps - CI/CD - Jenkins

- DevOps CI/CD pipelines for build, verify, deploy - using Jenkins.

Tutorial 4-E

Advanced Self-Learning Topics

• Take-home Exercises : Implement below.

• Testing

  • BDD (Behavior-Driven Development) with
  • Serenity BDD, Cucumber