Gateway-service

Microservice that acts as the unique access from the front-ends services to the back-end services.

The purpose to have a unique gateway access is for security purpose that is a common pattern in distributed architectures, used to decouple the internal API from the clients (fornt-end).

Other purposes are for monitor and resilence.

Introduction

We chose Spring Cloud Gateway to build a gateway-service and implement an API gateway. We improve resilence of the system by configuring circuit breaker with Spring Cloud Circuit Breaker, defining rate limiters with Spring Data Redis Reactive (where we store web sessions).

note: Vaadin flow and Hilla has its own mechanism for store web sessions, but in order to include rate limiters as a centralized component (i.e., for several micro-fonts) some how we repeat this functionality.

This microservice can have external access to the application running in a Kubernetes cluster by relying on the Kubernetes Ingress API.

Running on Docker Desktop

Create the image manually

./gradlew bootBuildImage

Publish the image to GitHub manually

./gradlew bootBuildImage \
   --imageName ghcr.io/rlegorreta/gateway-service \
   --publishImage \
   -PregistryUrl=ghcr.io \
   -PregistryUsername=rlegorreta \
   -PregistryToken=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

Publish the image to GitHub from the IntelliJ

To publish the image to GitHub from the IDE IntelliJ a file inside the directory .github/workflows/commit-stage.yml was created.

To validate the manifest file for kubernetes run the following command:

kubeval --strict -d k8s

This file compiles de project, test it (for this project is disabled for some bug), test vulnerabilities running skype, commits the code, sends a report of vulnerabilities, creates the image and lastly push the container image.

For detail information see .github/workflows/commit-stage.yml file.

Run the image inside the Docker desktop

docker run \
    --net ailegorretaNet \
    -p 8071:8071 \
    -e SPRING_PROFILES_ACTIVE=local \
    gateway-service

Or a better method use the docker-compose tool. Go to the directory ailegorreta-deployment/docker-platform and run the command:

docker-compose up

Run inside Kubernetes

Manually

If we do not use the Tilttool nd want to do it manually, first we need to create the image:

Fist step:

./gradlew bootBuildImage

Second step:

Then we have to load the image inside the minikube executing the command:

image load ailegorreta/gateway-service --profile ailegorreta 

To verify that the image has been loaded we can execute the command that lists all minikube images:

kubectl get pods --all-namespaces -o jsonpath="{..image}" | tr -s '[[:space:]]' '\n' | sort | uniq -c\n

Third step:

Then execute the deployment defined in the file k8s/deployment.yml with the command:

kubectl apply -f k8s/deplyment.yml

And after the deployment can be deleted executing:

kubectl apply -f k8s/deplymengt.yml

Fourth step:

For service discovery we need to create a service applying with the file: k8s/service.yml executing the command:

kubectl apply -f k8s/service.yml

And after the process we can delete the service executing:

kubectl deltete -f k8s/service.yml

Fifth step:

If we want to use the project outside kubernetes we have to forward the port as follows:

kubectl port-forward service/config-service 8071:80

Appendix:

If we want to see the logs for this pod we can execute the following command:

kubectl logs deployment/config-service

Using Tilt tool

To avoid all these boilerplate steps is much better and faster to use the Tilt tool as follows: first create see the file located in the root directory of the proyect called TiltFile. This file has the content:

# Tilt file for config-service
# Build
custom_build(
    # Name of the container image
    ref = 'gategay-service',
    # Command to build the container image
    command = './gradlew bootBuildImage --imageName $EXPECTED_REF',
    # Files to watch that trigger a new build
    deps = ['build.gradle', 'src']
)

# Deploy
k8s_yaml(['k8s/deployment.yml', 'k8s/service.yml'])

# Manage
k8s_resource('config-service', port_forwards=['8071'])

To execute all five steps manually we just need to execute the command:

tilt up

In order to see the log of the deployment process please visit the following URL:

http://localhost:10350

Or execute outside Tilt the command:

kubectl logs deployment/gateway-service

In order to undeploy everything just execute the command:

tilt down

To run inside a docker desktop the microservice need to use http://confsrv:8072 path

Reference Documentation

This microservice uses the recent Spring Gateway :

• Spring Boot Gateway
• Official Apache Maven documentation
• Spring Boot Maven Plugin Reference Guide
• Eureka Discovery Client
• Config Client Quick Start
• Spring Boot Actuator

Links to Springboot 3 Observability

https://tanzu.vmware.com/developer/guides/observability-reactive-spring-boot-3/

Baeldung:

https://www.baeldung.com/spring-boot-3-observability

Contact AI Legorreta

Feel free to reach out to AI Legorreta on web page.

Version: 2.0.0 ©LegoSoft Soluciones, S.C., 2023