docs: added spring boot hot reload project

examples/spring-boot-hot-reload/.project

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+<?xml version="1.0" encoding="UTF-8"?>
+<projectDescription>
+	<name>spring-boot-sample-devtools</name>
+	<comment></comment>
+	<projects>
+	</projects>
+	<buildSpec>
+		<buildCommand>
+			<name>org.eclipse.m2e.core.maven2Builder</name>
+			<arguments>
+			</arguments>
+		</buildCommand>
+	</buildSpec>
+	<natures>
+		<nature>org.eclipse.m2e.core.maven2Nature</nature>
+	</natures>
+</projectDescription>

examples/spring-boot-hot-reload/.settings/org.eclipse.m2e.core.prefs

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+activeProfiles=
+eclipse.preferences.version=1
+resolveWorkspaceProjects=true
+version=1

examples/spring-boot-hot-reload/README.md

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+# Spring Boot example project
+
+This example demonstrates Spring Boot running inside a Docker container (managed by a local Kubernetes cluster) with Spring Boot's dev tools enabled. We'll walk through live-restarting a Spring Boot service on compilation via Garden's hot reload functionality.
+
+## Prerequisites
+
+You'll need to have Java and [Maven](https://maven.apache.org/install.html) installed (follow the appropriate installation instructions for your platform).
+
+## Overview
+
+This project consists of a single module (in the `devtools` directory), which is a minimally modified version of the [Spring Boot devtools sample project found here](https://github.com/spring-projects/spring-boot/tree/master/spring-boot-samples/spring-boot-sample-devtools).
+
+We've changed the parent pom from `spring-boot-samples` to `spring-boot-starter-parent`, and added a dependency on `spring-boot-starter-actuator` (to enable the health check endpoint for k8s readiness and liveness probes). We've also removed the artificial 5 second delay that was added by the `slowRestart` method in `MyController`.
+
+## Usage
+
+First, run `mvn compile` in the `devtools` directory. This will download the service's dependencies and compile it. Afterwards, you should see the `target` directory appear (under `devtools`).
+
+Subsequent calls to `mvn compile` will be much faster, since the dependencies will have been cached by Maven.
+
+You can now deploy the service with hot reloading enabled e.g. by running
+
+```
+garden deploy --hot=devtools
+```
+
+This should produce output that's something like this:
+
+```
+Deploy 🚀
+
+✔ devtools                  → Building devtools:v-c6b9091207... → Done (
+took 0.4 sec)
+✔ devtools                  → Deploying version v-c6b9091207... → Done (
+took 67 sec)
+    → Ingress: http://spring-boot-hot-reload.local.app.garden
+🌻  Garden dashboard and API server running on http://localhost:50934
+
+🕑  Waiting for code changes
+```
+Open the ingress URL (http://spring-boot-hot-reload.local.app.garden above) in a web browser.
+
+Now, change the value of the `MESSAGE` constant in `devtools/src/main/java/sample/devtools/Message.java` to something else than `"Message"`, and run `mvn compile` (again in the `devtools` directory).
+
+This should trigger a hot reload. Refresh the the browser tab opened earlier, and you should see the change you made reflected in the header text.

examples/spring-boot-hot-reload/devtools/.gardenignore

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+src/main/java/**/*

examples/spring-boot-hot-reload/devtools/.gitignore

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+target

examples/spring-boot-hot-reload/devtools/Dockerfile

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+FROM maven:3.6.0-jdk-11-slim
+WORKDIR /app
+
+COPY pom.xml /app/pom.xml
+RUN mvn dependency:resolve
+
+RUN mkdir -p /app/target
+COPY src /app/src
+# RUN mvn install
+
+ENV JVM_OPTS "-XX:+UseCGroupMemoryLimitForHeap -XX:MaxRAMFraction=1"
+RUN mvn install
+# RUN mvn compile
+CMD ["mvn", "spring-boot:run"]
+
+EXPOSE 8080

examples/spring-boot-hot-reload/devtools/garden.yml

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+module:
+  description: Spring Boot devtools-sample module
+  type: container
+  name: devtools
+  hotReload:
+    sync:
+      - target: /app/target
+        source: target
+  services:
+    - name: devtools
+      ports:
+        - name: http
+          containerPort: 8080
+          servicePort: 80
+      healthCheck:
+        httpGet:
+          path: /actuator/health
+          port: http
+      ingresses:
+        - path: /
+          port: http

examples/spring-boot-hot-reload/devtools/pom.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<parent>
+		<groupId>org.springframework.boot</groupId>
+		<artifactId>spring-boot-starter-parent</artifactId>
+		<version>2.1.3.RELEASE</version>
+	</parent>
+	<artifactId>spring-boot-sample-devtools</artifactId>
+	<name>Spring Boot Developer Tools Sample</name>
+	<description>Spring Boot Developer Tools Sample</description>
+	<properties>
+		<main.basedir>${basedir}/../..</main.basedir>
+	</properties>
+	<dependencies>
+		<!-- Compile -->
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-web</artifactId>
+		</dependency>
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-thymeleaf</artifactId>
+		</dependency>
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-devtools</artifactId>
+		</dependency>
+		<dependency> <!-- Added for Garden example: For Kubernetes health checks -->
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-actuator</artifactId>
+		</dependency>
+		<!-- Test -->
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-test</artifactId>
+			<scope>test</scope>
+		</dependency>
+	</dependencies>
+	<build>
+		<plugins>
+			<plugin>
+				<groupId>org.springframework.boot</groupId>
+				<artifactId>spring-boot-maven-plugin</artifactId>
+			</plugin>
+		</plugins>
+	</build>
+</project>

examples/spring-boot-hot-reload/devtools/src/main/java/sample/devtools/Message.java

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+/*
+ * Copyright 2012-2018 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package sample.devtools;
+
+public final class Message {
+
+	/**
+	 * Sample message.
+	 */
+	public static String MESSAGE = "Message";
+
+	private Message() {
+	}
+
+}

examples/spring-boot-hot-reload/devtools/src/main/java/sample/devtools/MyController.java

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+/*
+ * Copyright 2012-2016 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package sample.devtools;
+
+import java.util.Date;
+
+import javax.annotation.PostConstruct;
+import javax.servlet.http.HttpSession;
+
+import org.springframework.stereotype.Controller;
+import org.springframework.ui.ModelMap;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.servlet.ModelAndView;
+
+@Controller
+public class MyController {
+
+	@GetMapping("/")
+	public ModelAndView get(HttpSession session) {
+		Object sessionVar = session.getAttribute("var");
+		if (sessionVar == null) {
+			sessionVar = new Date();
+			session.setAttribute("var", sessionVar);
+		}
+		ModelMap model = new ModelMap("message", Message.MESSAGE)
+				.addAttribute("sessionVar", sessionVar);
+		return new ModelAndView("hello", model);
+	}
+
+}

examples/spring-boot-hot-reload/devtools/src/main/java/sample/devtools/SampleDevToolsApplication.java

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+/*
+ * Copyright 2012-2016 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package sample.devtools;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class SampleDevToolsApplication {
+
+	public static void main(String[] args) {
+		SpringApplication.run(SampleDevToolsApplication.class, args);
+	}
+
+}

examples/spring-boot-hot-reload/devtools/src/main/resources/application.properties

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+# Enable remote support, for local development you don't need this line
+spring.devtools.remote.secret=secret
+management.endpoint.health.enabled=true
+management.endpoints.web.exposure.include=health
+# management.endpoints.web.exposure.include=health,info 

examples/spring-boot-hot-reload/devtools/src/main/resources/public/public.txt

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+public file

examples/spring-boot-hot-reload/devtools/src/main/resources/static/css/application.css

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+h1 {
+	color: green;
+}
+
+.content {
+	font-family: sans-serif;
+	border-top: 3px solid red;
+	padding-top: 30px;
+}

examples/spring-boot-hot-reload/devtools/src/main/resources/templates/hello.html

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+<!DOCTYPE html>
+<html xmlns:th="http://www.thymeleaf.org">
+	<head>
+		<title>Hello</title>
+	</head>
+	<body>
+		<h1 th:text="${message}">Header</h1>
+		<div class="content">
+			<h2 th:text="${sessionVar}">Session Var</h2>
+			Lorem ipsum dolor sit amet,
+			consectetur adipiscing elit. Cras ut fringilla augue, quis dictum
+			turpis. Sed tincidunt mi vel euismod viverra. Nulla facilisi.
+			Suspendisse mauris dolor, egestas ac leo at, porttitor ullamcorper
+			leo. Suspendisse consequat, justo ut rutrum interdum, nibh massa
+			semper dui, id sagittis tellus lectus at nibh. Etiam at scelerisque
+			nisi. Quisque vel eros tempor, fermentum sapien sed, gravida neque.
+			Fusce interdum sed dolor a semper. Morbi porta mauris a velit laoreet
+			viverra. Praesent et tellus vehicula, sagittis mi quis, faucibus urna.
+			Ut diam tortor, vehicula eget aliquam eget, elementum a odio. Fusce at
+			nisl sapien. Suspendisse potenti.
+		</div>
+	</body>
+</html>

examples/spring-boot-hot-reload/devtools/src/test/java/sample/devtools/SampleDevToolsApplicationIntegrationTests.java

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+/*
+ * Copyright 2012-2018 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package sample.devtools;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.test.context.SpringBootTest.WebEnvironment;
+import org.springframework.boot.test.web.client.TestRestTemplate;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.test.context.junit4.SpringRunner;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Integration tests for {@link SampleDevToolsApplication}.
+ *
+ * @author Andy Wilkinson
+ * @author Phillip Webb
+ */
+@RunWith(SpringRunner.class)
+@SpringBootTest(webEnvironment = WebEnvironment.RANDOM_PORT)
+public class SampleDevToolsApplicationIntegrationTests {
+
+	@Autowired
+	private TestRestTemplate restTemplate;
+
+	@Test
+	public void testStaticResource() {
+		ResponseEntity<String> entity = this.restTemplate
+				.getForEntity("/css/application.css", String.class);
+		assertThat(entity.getStatusCode()).isEqualTo(HttpStatus.OK);
+		assertThat(entity.getBody()).contains("color: green;");
+	}
+
+	@Test
+	public void testPublicResource() {
+		ResponseEntity<String> entity = this.restTemplate.getForEntity("/public.txt",
+				String.class);
+		assertThat(entity.getStatusCode()).isEqualTo(HttpStatus.OK);
+		assertThat(entity.getBody()).contains("public file");
+	}
+
+	@Test
+	public void testClassResource() {
+		ResponseEntity<String> entity = this.restTemplate
+				.getForEntity("/application.properties", String.class);
+		assertThat(entity.getStatusCode()).isEqualTo(HttpStatus.NOT_FOUND);
+	}
+
+}

examples/spring-boot-hot-reload/garden.yml

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+project:
+  name: spring-boot-hot-reload
+  environments:
+    - name: local
+      providers:
+        - name: local-kubernetes