Demo app

This repo contain the demo app.

Application source code

For demo app starting point refer to this and with changes explained here.

Further or Mysql compatibility the line is added in application.properties:

spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.MySQL8Dialect

Generate the WAR file by running the mvn package command. The resulting file will be located in target/gs-mysql-data-0.1.0.war.

Docker Build

In the app-docker folder you find the Dockerfile containing:

FROM bitnami/tomcat:9.0
COPY gs-mysql-data-0.1.0.war /opt/bitnami/tomcat/webapps_default/

Build:

docker build -t DOCKER_USERNAME/spring-java-app .

Push:

docker push DOCKER_USERNAME/spring-java-app:latest

Docker compose yaml for testing image:

version: '2'

services:
    myapp:
    image: 'DOCKER_USERNAME/spring-java-app'
    environment:
      - 'SPRING_APPLICATION_JSON={"spring": {"datasource":{"url": "jdbc:mysql://mariadb:3306/db_example", "username": "springuser", "password": "ThePassword"}}}'
      - ALLOW_EMPTY_PASSWORD=yes
    depends_on:
      - mariadb
    ports:
     - '8080:8080

test:

docker compose-up
curl 'localhost:8080/gs-mysql-data-0.1.0/demo/all'
curl 'localhost:8080/gs-mysql-data-0.1.0/demo/add?name=First&[email protected]'
curl 'localhost:8080/gs-mysql-data-0.1.0/demo/all'

Helm chart

The hem chart in this repo is the result of

helm fetch bitnami/tomcat --untar

add the following part in _pod.tpl for allowing the composition of required env variable

  - name: DBENDPOINT
    valueFrom:
      secretKeyRef:
        name: {{ .Values.mariadb.db.secretname }}
        key: endpoint
  - name: DBUSERNAME
    valueFrom:
      secretKeyRef:
        name: {{ .Values.mariadb.db.secretname }}
        key: username
  - name: DBNAME
    value:  {{ .Values.mariadb.db.dbname }}
  - name: DBPASSWD
    valueFrom:
      secretKeyRef:
        name: {{ .Values.mariadb.db.secretname }}
        key: password
  - name: SPRING_APPLICATION_JSON
    value: {{"'{\"spring\": {\"datasource\":{\"url\": \"jdbc:mysql://$(DBENDPOINT):3306/$(DBNAME)?useSSL=false\",\"username\": \"$(DBUSERNAME)\", \"password\": \"$(DBPASSWD)\"}}}'"}}

modify in values:

image:
   registry: docker.io
   repository: DOCKER_USERNAME/spring-java-app
   tag: latest

add to values.yaml:

mariadb:

  enabled: false
  replication:
    enabled: false
  db:
    secretname: mysqldb
    dbname: db_example

NB: secretname refer to crossplane secrets for connection details.

Change in values.yaml for LoadBalancer to NodePort:

service:
  ## @param service.type Kubernetes Service type
  ## For minikube, set this to NodePort, elsewhere use LoadBalancer
  ##
  type: NodePort
  ## @param service.port Service HTTP port
  ##
  port: 80
  ## @param service.nodePort Kubernetes http node port
  ## ref: https://kubernetes.io/docs/concepts/services-networking/service/#type-nodeport
  ##
  nodePort: "30080"

and for setting Kuma ingress with encryption:

ingress:
  ## @param ingress.enabled Enable ingress controller resource
  ##
  enabled: true
  ## @param ingress.certManager Set this to true in order to add the corresponding annotations for cert-manager
  ##
  certManager: true
  ## @param ingress.hostname Default host for the ingress resource
  ##
  hostname: <HOSTNAME>
  ## @param ingress.annotations Ingress annotations
  ## For a full list of possible ingress annotations, please see
  ## ref: https://github.com/kubernetes/ingress-nginx/blob/master/docs/user-guide/nginx-configuration/annotations.md
  ##
  ## If certManager is set to true, annotation kubernetes.io/tls-acme: "true" will automatically be set
  ##
  annotations:
    kubernetes.io/ingress.class: "kong"
    cert-manager.io/cluster-issuer: <CLUSTER-ISSUER NAME>
  ## @param ingress.tls Enable TLS configuration for the hostname defined at `ingress.hostname` parameter
  ## TLS certificates will be retrieved from a TLS secret with name: {{- printf "%s-tls" .Values.ingress.hostname }}
  ## You can use the ingress.secrets parameter to create this TLS secret, relay on cert-manager to create it, or
  ## let the chart create self-signed certificates for you
  ##
  tls: true

For having the pod deployed and Joined to mesh the namespace in which you deploy must have this further annotation, see file kuma-dataplane.yaml in various directory:

  annotations:
    kuma.io/sidecar-injection: enabled
    kuma.io/mesh: default"

run:

helm dependency update .
helm install -n app --create-namespace  spring-java .

test:

https://<HOSTNAME>/gs-mysql-data-0.1.0/demo/add?name=First&[email protected]
https://<HOSTNAME>/gs-mysql-data-0.1.0/demo/all

The result is the app deployed in the cluster using Porworx as storage:

The app has a valid ssl certificate exposed by the Kong ingress and registered in the Kuma mesh:

The application log is further availale in Grafana using Loki source:

Old Notes for using with Mariadb

The add dependency in Chart.yaml (not in requirements fiels since in deprecated, changed to a more recent mariadb image (statesful api version error)):

- name: mariadb
  version: 9.4.2
  repository: https://charts.bitnami.com/bitnami
  condition: mariadb.enabled
  tags:
    - spring-java-app-database

since this mariadb cannot receive values in dependency, untar mariadb under chart, add the required parameter to create the db, the user and passw:

auth:
  database: db_example
  username: "springuser"
  password: "ThePassword"

add to _helpers.tpl

{{/*
Create a default fully qualified app name.
We truncate at 63 chars because some Kubernetes name fields are limited to this (by the DNS naming spec).
*/}}
{{- define "mariadb.fullname" -}}
{{- printf "%s-%s" .Release.Name "mariadb" | trunc 63 | trimSuffix "-" -}}
{{- end -}}

create spring-secret.yaml in template directory:

apiVersion: v1
kind: Secret
metadata:
  name: {{ template "tomcat.fullname" . }}-spring
  labels:
    app: {{ template "tomcat.fullname" . }}
    chart: "{{ .Chart.Name }}-{{ .Chart.Version }}"
    release: "{{ .Release.Name }}"
    heritage: "{{ .Release.Service }}"
type: Opaque
data:
  spring-db: {{ printf "{\"spring\": {\"datasource\":{\"url\": \"jdbc:mysql://%s:3306/%s\", \"username\": \"%s\", \"password\": \"%s\"}}}" (include "mariadb.fullname" .) .Values.mariadb.db.name .Values.mariadb.db.user .Values.mariadb.db.password | b64enc }}

add to _pod.tpl

 - name: SPRING_APPLICATION_JSON
    valueFrom:
      secretKeyRef:
        name: {{ template "common.names.fullname" . }}-spring
        key: spring-db