Java Based microservices¶

This note address simple implementation and deployment detail of the two microservices used in the demonstration.

Tenant Manager¶

This is a Java Quarkus app, with Reactive REST API, persistence to RDS Postgresql via JPA and Panache. We recommend to review the following Quarkus guides to get started on this stack.

• GENERATING JAX-RS RESOURCES WITH PANACHE.
• Reactive messaging.
• Kubernetes extension.

The service supports basic CRUD operation on the Tenant entity. Panache is doing the JPA mapping to JDBC. The OpenAPI extension is added to offer a swagger User interface so it easier to test the component. We use the Repository pattern for the Panache.

The home page of the application from which we can access to the Swagger UI

The Swagger UI with the defined OpenAPI

The Stream processing in Flink application will code the GET /api/v1/tenants/{tenantID} API to get the information about the company doing one of the big data batch processing.

Run locally¶

• Start docker compose for a local postgresql

docker compose up -d

• Start quarkus in dev mode: quarkus dev if you have the CLI, or mvn dev with maven.

• Verify the service works locally with command like:

# Get all tenants in the database
curl -X GET localhost:8080/api/v1/tenants
# Get one tenant
curl -X GET localhost:8080/api/v1/tenants/comp_2

Build docker image and push it to ECR¶

• Create the ECR repository: named jbcodeforce/demo-saas-tenant-mgr

./scripts/createECRrepository.sh
# OR to a new name
./scripts/createECRrepository.sh anothername/demo-saas-tenant-mgr

The result may look like:

{
    "repository": {
        "repositoryArn": "arn:aws:ecr:us-west-2:v..accountnumber:repository/jbcodeforce/demo-saas-tenant-mgr",
        "registryId": "4..accountnumber",
        "repositoryName": "jbcodeforce/demo-saas-tenant-mgr",
        "repositoryUri": "4..accountnumber.dkr.ecr.us-west-2.amazonaws.com/jbcodeforce/demo-saas-tenant-mgr",
        "createdAt": "2022-12-28T09:48:16-08:00",
        "imageTagMutability": "MUTABLE",
        "imageScanningConfiguration": {
            "scanOnPush": false
        },
        "encryptionConfiguration": {
            "encryptionType": "AES256"
        }
    }
}

• Be sure to be logged to the ECR registry with a command like:

aws ecr get-login-password --region us-west-2 | docker login --username AWS --password-stdin 4..accountnumber.dkr.ecr.us-west-2.amazonaws.com

• Build and push the image using the ECR base URL for your region and account:

./scripts/buildAll.sh 40..accountnumber.dkr.ecr.us-west-2.amazonaws.com

# verify
docker images | grep demo-saas-tenant-mgr

The reference documentation for ECR push image

Deploy the app to EKS¶

The following figure illustrates what we are deploying:

• One VPC with 2 Availability zones and one public and private subnet per AZ.
• EKS cluster defined in private subnet with 2 nodes
• One namespace to get the core of AnyCompany services (Control plane components)
• Amazon RDS to persist Tenant data

RDS Postgresql database¶

As a pre-requisite we need one instance of RDS postgresql database. It should have been created with the solution CDK, in setup/saas-solution-cdk.

See CDK python doc

Kubernetes extension for Quarkus¶

We recommend to read the Kubernetes Quarkus guide. The Kubernetes extension was added to the pom.xml and a kubernetes.yml file is created at each build and includes deployment, services, service account YAML definitions. To tune this generated file the following declarations were added to the application.properties:

quarkus.kubernetes.namespace=demo-saas-core
quarkus.container-image.registry=4....dkr.ecr.us-west-2.amazonaws.com/jbcodeforce/demo-saas-tenant-mgr
quarkus.container-image.tag=latest
quarkus.kubernetes.env.secrets=saas-secret

Once EKS cluster is operational, using kubectl can deploy the application:

kubectl apply -f target/kubernetes/kubernetes.yml