Added quickstart demonstrating dapr.io integration with jkube (#2035)

quickstarts/gradle/dapr-hello-world/README.md

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+---
+name: "Gradle :: dapr-hello-world"
+
+description: 
+
+  Dapr hello world application deployed in Kubernetes using Eclipse JKube.
+
+  The application contains a single controller HelloWorldController.java that prints 'Hello World'.
+
+---
+
+# Eclipse JKube Dapr Gradle Quickstart
+
+This is a demo gradle application based on Dapr framework which can be deployed to 
+Kubernetes with the help of Kubernetes JKube Gradle Plugin.
+
+## How to Build?
+In order to build,you will need to install Dapr in kubernetes
+
+- Install Dapr in kubernetes
+  ```shell script
+  $ dapr init -k
+  ```
+
+- Verify installation
+  ```shell script
+  $ dapr status -k
+  ```
+
+- If required, update installation
+  ```shell script
+  $ dapr upgrade -k --runtime-version=x.x.x
+  ```
+
+## Deploying to Kubernetes
+Kubernetes Gradle Plugin is already added to the project plugins section.
+You can deploy it using the usual Kubernetes Gradle Plugin tasks, just make sure you are logged into
+a Kubernetes cluster:
+
+For the Dapr application to work in a Kubernetes cluster it needs following annotation in the `deployment.yaml` file under spec, template metadata section 
+
+```yaml
+annotations:
+  dapr.io/enabled: "true"
+  dapr.io/app-id: "dapr-hello-world"
+  dapr.io/app-port: "8085"
+  dapr.io/config: "appconfig"
+```
+
+In order to deploy the application, you need to run the Kubernetes Gradle Plugin build, resource, and apply goals:
+
+```shell script
+# Kubernetes
+$ gradle clean build k8sBuild k8sResource k8sApply
+# OpenShift
+$ gradle clean build ocBuild ocResource ocApply
+```
+
+If you are working with slow internet connection then readiness and liveness probe may timeout uncomment timeout and delay related annotation from above
+
+If you need time observability in your application you can use zipkin and Dapr appconfig, installation instruction for zipkin with appconfig is given in zipkininstallation.sh
+

quickstarts/gradle/dapr-hello-world/appconfig.yaml

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+#
+# Copyright (c) 2019 Red Hat, Inc.
+# This program and the accompanying materials are made
+# available under the terms of the Eclipse Public License 2.0
+# which is available at:
+#
+#     https://www.eclipse.org/legal/epl-2.0/
+#
+# SPDX-License-Identifier: EPL-2.0
+#
+# Contributors:
+#   Red Hat, Inc. - initial API and implementation
+#
+
+apiVersion: dapr.io/v1alpha1
+kind: Configuration
+metadata:
+  name: appconfig
+spec:
+  tracing:
+    samplingRate: "1"
+    zipkin:
+      endpointAddress: "http://zipkin.default.svc.cluster.local:9411/api/v2/spans"

quickstarts/gradle/dapr-hello-world/build.gradle

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+buildscript {
+  repositories {
+    mavenCentral()
+    mavenLocal()
+  }
+  dependencies {
+    classpath 'io.fabric8:kubernetes-client'
+  }
+}
+
+plugins {
+  id 'java'
+  id 'org.springframework.boot' version '2.7.8'
+  id 'io.spring.dependency-management' version '1.0.15.RELEASE'
+  id 'org.eclipse.jkube.kubernetes' version '1.11.0'
+  id 'org.eclipse.jkube.openshift' version '1.11.0'
+}
+
+group = 'org.eclipse.jkube.quickstart.gradle.dapr'
+version = '0.0.1-SNAPSHOT'
+sourceCompatibility = '11'
+
+repositories {
+  mavenCentral()
+}
+
+dependencies {
+  implementation 'org.springframework.boot:spring-boot-starter-web'
+  implementation 'io.dapr:dapr-sdk-springboot:1.7.1'
+}
+
+tasks.named('test') {
+  useJUnitPlatform()
+}
+
+tasks.register('zipkinInstall') {
+  doLast {
+    new io.fabric8.kubernetes.client.KubernetesClientBuilder().build().withCloseable { kc ->
+      kc.load(new FileInputStream(new File('./zipkin.yaml'))).withGracePeriod(0).delete()
+      kc.load(new FileInputStream(new File('./appconfig.yaml'))).withGracePeriod(0).delete()
+      kc.load(new FileInputStream(new File('./zipkin.yaml'))).create()
+      kc.load(new FileInputStream(new File('./appconfig.yaml'))).create()
+    }
+  }
+}
+
+tasks.register('zipkinUninstall') {
+  doLast {
+    new io.fabric8.kubernetes.client.KubernetesClientBuilder().build().withCloseable { kc ->
+      kc.load(new FileInputStream(new File('./zipkin.yaml'))).withGracePeriod(0).delete()
+      kc.load(new FileInputStream(new File('./appconfig.yaml'))).withGracePeriod(0).delete()
+    }
+  }
+}
+
+kubernetes {
+  resources {
+    annotations {
+      pod = [
+          'dapr.io/enabled' : true,
+          'dapr.io/app-id'  : "dapr-hello-world",
+          'dapr.io/app-port': "8085",
+          // if you want to trace application then run gradle zipkinInstall
+          'dapr.io/config' : "appconfig"
+      ]
+    }
+  }
+}
+
+openshift {
+  resources {
+    annotations {
+      pod = [
+          'dapr.io/enabled' : true,
+          'dapr.io/app-id'  : "dapr-hello-world",
+          'dapr.io/app-port': "8085",
+          // if you want to trace application then run gradle zipkinInstall
+          'dapr.io/config' : "appconfig"
+      ]
+    }
+  }
+}

quickstarts/gradle/dapr-hello-world/gradle.properties

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+#
+# Copyright (c) 2019 Red Hat, Inc.
+# This program and the accompanying materials are made
+# available under the terms of the Eclipse Public License 2.0
+# which is available at:
+#
+#     https://www.eclipse.org/legal/epl-2.0/
+#
+# SPDX-License-Identifier: EPL-2.0
+#
+# Contributors:
+#   Red Hat, Inc. - initial API and implementation
+#
+
+jkube.generator.name = jkube-quickstarts/%a:%l
+jkube.image.name = dapr-hello-world
+jkube.generator.build.imagePullPolicy = Always
+jkube.enricher.jkube-controller.replicaCount = 1
+jkube.enricher.jkube-service.type = LoadBalancer

quickstarts/gradle/dapr-hello-world/gradle/wrapper/gradle-wrapper.properties

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+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-7.6-bin.zip
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists

quickstarts/gradle/dapr-hello-world/gradlew.bat

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+@rem
+@rem Copyright 2015 the original author or authors.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem      https://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+
+@if "%DEBUG%"=="" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%"=="" set DIRNAME=.
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Resolve any "." and ".." in APP_HOME to make it shorter.
+for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if %ERRORLEVEL% equ 0 goto execute
+
+echo.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto execute
+
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %*
+
+:end
+@rem End local scope for the variables with windows NT shell
+if %ERRORLEVEL% equ 0 goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega

quickstarts/gradle/dapr-hello-world/settings.gradle

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+rootProject.name = 'dapr-hello-world'

quickstarts/gradle/dapr-hello-world/src/main/java/com/example/demo/DaprHelloWorldApplication.java

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+/**
+ * Copyright (c) 2019 Red Hat, Inc.
+ * This program and the accompanying materials are made
+ * available under the terms of the Eclipse Public License 2.0
+ * which is available at:
+ *
+ *     https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Contributors:
+ *   Red Hat, Inc. - initial API and implementation
+ */
+package com.example.demo;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class DaprHelloWorldApplication {
+	public static void main(String[] args) {
+		SpringApplication.run(DaprHelloWorldApplication.class, args);
+	}
+}

quickstarts/gradle/dapr-hello-world/src/main/java/com/example/demo/controller/HelloWorldController.java

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+/**
+ * Copyright (c) 2019 Red Hat, Inc.
+ * This program and the accompanying materials are made
+ * available under the terms of the Eclipse Public License 2.0
+ * which is available at:
+ *
+ *     https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Contributors:
+ *   Red Hat, Inc. - initial API and implementation
+ */
+package com.example.demo.controller;
+
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+public class HelloWorldController {
+	@GetMapping("/wish")
+	public String wish() {
+		return "Hello World";
+	}
+}

quickstarts/gradle/dapr-hello-world/src/main/resources/application.properties

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+#
+# Copyright (c) 2019 Red Hat, Inc.
+# This program and the accompanying materials are made
+# available under the terms of the Eclipse Public License 2.0
+# which is available at:
+#
+#     https://www.eclipse.org/legal/epl-2.0/
+#
+# SPDX-License-Identifier: EPL-2.0
+#
+# Contributors:
+#   Red Hat, Inc. - initial API and implementation
+#
+
+spring.application.name=dapr-hello-world
+server.port=8085