Java Applications

Even though not strictly a module, this library contains a lot of utility functions to help you deploy Java applications. This page contains some ways these functions can be used.

All-in-one

This example contains the deployment of a simple spring boot based application. It should be located somewhere like lib/my-application.libsonnet.

jsonnetyaml

local k = (import 'cloudflight-libsonnet/prelude.libsonnet');
{
  _config+:: {
    myApplication: {
      name: 'my-application',
      image: error '$._config.myApplication.image must be defined',
    },
  },
  myApplication: {
    deployment: k.util.java.deployment.new(
      name=$._config.myApplication.name,
      image=$._config.myApplication.image,
      containerMixin=k.core.v1.container.livenessProbe.withInitialDelaySeconds(60),
    ),
    service: k.util.serviceFor(self.deployment),
    route: k.util.routeFor(self.service, 'hello.example.com'),
  },
}

apiVersion: v1
kind: Service
metadata:
labels:
    name: my-application
name: my-application
namespace: test-java
spec:
ports:
- name: my-application-http
    port: 8080
    targetPort: 8080
- name: my-application-actuator
    port: 9080
    targetPort: 9080
selector:
    name: my-application
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: my-application
namespace: test-java
spec:
minReadySeconds: 10
replicas: 1
revisionHistoryLimit: 10
selector:
    matchLabels:
    name: my-application
template:
    metadata:
    labels:
        name: my-application
    spec:
    containers:
    - env:
        - name: SPRING_PROFILES_ACTIVE
        value: kubernetes
        image: helloworld:latest
        imagePullPolicy: IfNotPresent
        livenessProbe:
        failureThreshold: 5
        initialDelaySeconds: 30
        periodSeconds: 10
        successThreshold: 1
        tcpSocket:
            port: 8080
        timeoutSeconds: 1
        name: my-application
        ports:
        - containerPort: 8080
        name: http
        - containerPort: 9080
        name: actuator
        readinessProbe:
        failureThreshold: 5
        httpGet:
            path: /actuator/health
            port: 18080
        initialDelaySeconds: 30
        periodSeconds: 10
        successThreshold: 1
        timeoutSeconds: 1
        resources:
        limits:
            cpu: 500m
            memory: 1Gi
        requests:
            cpu: 100m
            memory: 1Gi
---
apiVersion: route.openshift.io/v1
kind: Route
metadata:
name: my-application
namespace: test-java
spec:
host: hello.example.com
path: /
port:
    targetPort: 8080
tls:
    insecureEdgeTerminationPolicy: Redirect
    termination: Edge
to:
    kind: Service
    name: my-application

Switch between the tabs to see the rendered output

DIY

If you have the need for further customization, you can pick and choose parts of the library you would like to use.

In this example, we want to modify the container so we use the util.java.container.new() to get a base structure and extend it. This way, we still have the defaults set, but are able to customize them to our hearts content.

jsonnetyaml

local k = (import 'cloudflight-libsonnet/prelude.libsonnet');
{
  _config+:: {
    myApplication: {
      name: 'my-application',
      image: error '$._config.myApplication.image must be defined',
    },
  },
  myApplication: {
    deployment: k.apps.v1.deployment.new(
                  name=$._config.myApplication.name,
                  replicas=2,
                  containers=[
                    k.util.java.container.new($._config.myApplication.name, $._config.myApplication.image)
                    + k.core.v1.container.withVolumeMounts([
                      k.core.v1.volumeMount.new(name='temp', mountPath='/opt/cache'),
                    ]),
                  ]
                )
                + k.apps.v1.deployment.spec.template.spec.withVolumes([
                  k.core.v1.volume.fromEmptyDir(name='temp'),
                ]),
    service: k.util.serviceFor(self.deployment),
    route: k.util.routeFor(self.service, 'hello.example.com'),
  },
}

apiVersion: v1
kind: Service
metadata:
  labels:
    name: my-application
  name: my-application
  namespace: test-java-diy
spec:
  ports:
  - name: my-application-http
    port: 8080
    targetPort: 8080
  - name: my-application-actuator
    port: 9080
    targetPort: 9080
  selector:
    name: my-application
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: my-application
  namespace: test-java-diy
spec:
  minReadySeconds: 10
  replicas: 2
  revisionHistoryLimit: 10
  selector:
    matchLabels:
      name: my-application
  template:
    metadata:
      labels:
        name: my-application
    spec:
      containers:
      - env:
        - name: SPRING_PROFILES_ACTIVE
          value: kubernetes
        image: helloworld:latest
        imagePullPolicy: IfNotPresent
        livenessProbe:
          failureThreshold: 5
          initialDelaySeconds: 30
          periodSeconds: 10
          successThreshold: 1
          tcpSocket:
            port: 8080
          timeoutSeconds: 1
        name: my-application
        ports:
        - containerPort: 8080
          name: http
        - containerPort: 9080
          name: actuator
        readinessProbe:
          failureThreshold: 5
          httpGet:
            path: /actuator/health
            port: 18080
          initialDelaySeconds: 30
          periodSeconds: 10
          successThreshold: 1
          timeoutSeconds: 1
        resources:
          limits:
            cpu: 500m
            memory: 1Gi
          requests:
            cpu: 100m
            memory: 1Gi
        volumeMounts:
        - mountPath: /opt/cache
          name: temp
      volumes:
      - emptyDir: {}
        name: temp
---
apiVersion: route.openshift.io/v1
kind: Route
metadata:
  name: my-application
  namespace: test-java-diy
spec:
  host: hello.example.com
  path: /
  port:
    targetPort: 8080
  tls:
    insecureEdgeTerminationPolicy: Redirect
    termination: Edge
  to:
    kind: Service
    name: my-application

---

Last update: 2022-07-08