This library is dedicated for Spring Boot application. Once it is included and enabled it is creating Istio resources on the current Kubernetes cluster basing on the code and annotation fields @EnableIstio.

• Java 17 or higher
• Kubernetes cluster with Istio installed
• kubectl configured to access your cluster

Add the dependency to your Maven pom.xml:

<dependency>
  <groupId>com.github.piomin</groupId>
  <artifactId>istio-spring-boot-starter</artifactId>
  <version>2.0.0</version>
</dependency>

The library provides autoconfigured support for creating Istio resources on Kubernetes basing on annotation @EnableIstio.

@SpringBootApplication
@EnableIstio(version = "v1")
public class CallmeApplication {

	public static void main(String[] args) {
		SpringApplication.run(CallmeApplication.class, args);
	}
	
}

We can enable additional things. For example, we can enable Gateway and VirtualService with fault injection or matches in VirtualService.

@SpringBootApplication
@EnableIstio(enableGateway = true,
        fault = @Fault(type = FaultType.ABORT, percentage = 50),
        matches = { @Match("/hello"), @Match("/hello2") })
public class SampleAppWithIstio {
    public static void main(String[] args) {
        SpringApplication.run(SampleAppWithIstio.class, args);
    }
}

The @EnableIstio annotation provides the following configuration options:

All @EnableIstio fields can be overridden via application.properties / application.yml using the prefix istio.spring. Properties take precedence over annotation values when set.

Example:

istio:
  spring:
    version: v1
    timeout: 3000
    number-of-retries: 2
    enable-gateway: true
    domain: example.com
    fault:
      type: ABORT
      percentage: 10
      http-status: 503

The library automatically creates the following Istio resources during application startup:

DestinationRule: Defines policies for traffic routing, including load balancing and connection pool settings.
VirtualService: Configures request routing, retries, timeouts, matches, and fault injection.
Gateway: Exposes the service to external traffic.

Here's the architecture of a presented solution. Spring Boot Istio Library is included in the target application. It uses Java Istio Client to communication with istiod. During application startup the library is communicating with Istio API to create DestinationRule and VirtualService objects.