Kubernetes HostAliases property

Allow the generation of hostAliases property from Deployment

Signed-off-by: Vincent Sourtin <[email protected]>

annotations/kubernetes-annotations/src/main/java/io/dekorate/kubernetes/annotation/KubernetesApplication.java

@@ -210,6 +210,11 @@
    * The image pull secret
    */
   String[] imagePullSecrets() default {};
+
+  /**
+   * The hostAliases
+   */
+  HostAlias[] hostAliases() default {};
 
   /**
    * The liveness probe.

core/src/main/java/io/dekorate/AbstractKubernetesHandler.java

@@ -28,6 +28,7 @@
 import io.dekorate.kubernetes.config.Container;
 import io.dekorate.kubernetes.config.Env;
 import io.dekorate.kubernetes.config.BaseConfig;
+import io.dekorate.kubernetes.config.HostAlias;
 import io.dekorate.kubernetes.config.Label;
 import io.dekorate.kubernetes.config.Mount;
 import io.dekorate.kubernetes.config.PersistentVolumeClaimVolume;
@@ -40,6 +41,7 @@
 import io.dekorate.kubernetes.decorator.AddCommitIdAnnotationDecorator;
 import io.dekorate.kubernetes.decorator.AddConfigMapVolumeDecorator;
 import io.dekorate.kubernetes.decorator.AddEnvVarDecorator;
+import io.dekorate.kubernetes.decorator.AddHostAliasesDecorator;
 import io.dekorate.kubernetes.decorator.AddImagePullSecretDecorator;
 import io.dekorate.kubernetes.decorator.AddLabelDecorator;
 import io.dekorate.kubernetes.decorator.AddLivenessProbeDecorator;
@@ -129,6 +131,10 @@ protected void addDecorators(String group, C config) {
       resources.decorate(group, new AddImagePullSecretDecorator(config.getName(), imagePullSecret));
     }
 
+    for (HostAlias hostAlias : config.getHostAliases()) {
+      resources.decorate(new AddHostAliasesDecorator(config.getName(), hostAlias));
+    }
+
     for (Container container : config.getSidecars()) {
       resources.decorate(group, new AddSidecarDecorator(config.getName(), container));
     }
@@ -200,7 +206,7 @@ protected void addDecorators(String group, C config) {
     if (Strings.isNotNullOrEmpty(config.getRequestResources() .getMemory())) {
       resources.decorate(group, new ApplyRequestsMemoryDecorator(config.getName(), config.getName(), config.getRequestResources() .getMemory()));
     }
- 
+
   }
 
   private static void validateVolume(SecretVolume volume) {

core/src/main/java/io/dekorate/kubernetes/annotation/Base.java

@@ -165,6 +165,13 @@
    * The image pull secret
    */
   String[] imagePullSecrets() default {};
+
+  /**
+   * Host aliases
+   *
+   * @return The host aliases
+   */
+  HostAlias[] hostAliases() default {};
 
   /**
    * The liveness probe.

core/src/main/java/io/dekorate/kubernetes/annotation/HostAlias.java

@@ -0,0 +1,31 @@
+/**
+ * Copyright 2018 The original 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 io.dekorate.kubernetes.annotation;
+
+public @interface HostAlias {
+
+  /**
+   * Ip address to resolve to.
+   * @return the ip address.
+   */
+  String ip() default "";
+
+  /**
+   * List of hostnames (comma separated)
+   * @return the hostnames
+   */
+  String hostnames() default "";
+}

core/src/main/java/io/dekorate/kubernetes/decorator/AddHostAliasesDecorator.java

@@ -0,0 +1,68 @@
+/**
+ * Copyright 2018 The original 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 io.dekorate.kubernetes.decorator;
+
+import io.dekorate.kubernetes.config.HostAlias;
+import io.dekorate.utils.Strings;
+import io.fabric8.kubernetes.api.builder.Predicate;
+import io.fabric8.kubernetes.api.model.HostAliasBuilder;
+import io.fabric8.kubernetes.api.model.ObjectMeta;
+import io.fabric8.kubernetes.api.model.PodSpecFluent;
+
+import java.util.Arrays;
+import java.util.Objects;
+
+public class AddHostAliasesDecorator extends NamedResourceDecorator<PodSpecFluent<?>> {
+
+ private final HostAlias hostAlias;
+
+  public AddHostAliasesDecorator(String deploymentName, HostAlias hostAlias) {
+    super(deploymentName);
+    this.hostAlias = hostAlias;
+  }
+
+  public void andThenVisit(PodSpecFluent<?> podSpec, ObjectMeta resourceMeta) {
+    if (Strings.isNotNullOrEmpty(hostAlias.getIp()) && Strings.isNotNullOrEmpty(hostAlias.getHostnames())) {
+      Predicate<HostAliasBuilder> matchingHostAlias = host -> {
+        if (host.getIp() != null)
+          return host.getIp().equals(hostAlias.getIp());
+        return false;
+      };
+
+      podSpec.removeMatchingFromHostAliases(matchingHostAlias);
+
+      podSpec.addNewHostAlias()
+        .withIp(hostAlias.getIp())
+        .withHostnames(Arrays.asList(hostAlias.getHostnames().split(",")))
+        .endHostAlias();
+    }
+  }
+
+  @Override
+  public boolean equals(Object o) {
+    if (this == o) return true;
+    if (o == null || getClass() != o.getClass()) return false;
+    AddHostAliasesDecorator that = (AddHostAliasesDecorator) o;
+    return Objects.equals(hostAlias, that.hostAlias);
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(hostAlias);
+  }
+}

examples/kubernetes-example-with-hostaliases/Dockerfile

@@ -0,0 +1,4 @@
+FROM openjdk:8u171-alpine3.7
+RUN apk --no-cache add curl
+COPY target/*.jar kubernetes-example-with-hostaliases.jar
+CMD java ${JAVA_OPTS} -jar kubernetes-example-with-hostaliases.jar

examples/kubernetes-example-with-hostaliases/pom.xml

@@ -0,0 +1,78 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+Copyright 2018 The original 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.
+
+-->
+<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">
+  <parent>
+    <artifactId>examples</artifactId>
+    <groupId>io.dekorate</groupId>
+    <version>0.12-SNAPSHOT</version>
+  </parent>
+  <modelVersion>4.0.0</modelVersion>
+
+  <groupId>io.dekorate</groupId>
+  <artifactId>kubernetes-example-with-hostaliases</artifactId>
+  <name>Dekorate :: Examples :: Kubernetes with hostAliases</name>
+
+  <properties>
+    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
+    <java.version>1.8</java.version>
+
+    <version.spring-boot>2.1.13.RELEASE</version.spring-boot>
+  </properties>
+
+  <dependencies>
+    <dependency>
+      <groupId>io.dekorate</groupId>
+      <artifactId>kubernetes-annotations</artifactId>
+      <version>${project.version}</version>
+    </dependency>
+
+    <dependency>
+      <groupId>org.springframework.boot</groupId>
+      <artifactId>spring-boot-starter-web</artifactId>
+      <version>${version.spring-boot}</version>
+    </dependency>
+
+    <!-- Testing -->
+    <dependency>
+      <groupId>io.dekorate</groupId>
+      <artifactId>kubernetes-junit-starter</artifactId>
+      <version>${project.version}</version>
+      <scope>test</scope>
+    </dependency>
+  </dependencies>
+
+  <build>
+    <plugins>
+      <plugin>
+        <groupId>org.springframework.boot</groupId>
+        <artifactId>spring-boot-maven-plugin</artifactId>
+        <version>${version.spring-boot}</version>
+        <executions>
+          <execution>
+            <goals>
+              <goal>repackage</goal>
+            </goals>
+          </execution>
+        </executions>
+      </plugin>
+    </plugins>
+  </build>
+
+
+</project>

examples/kubernetes-example-with-hostaliases/readme.md

@@ -0,0 +1,60 @@
+# Add hostAliases property Example 
+
+An example that demonstrates the use of `@KubernetesApplication` in order to add hostAliases property to a deployment.
+To access the `@KubernetesApplication` annotation you just need to have the following dependency in your
+class path:
+
+    <dependency>
+      <groupId>io.dekorate</groupId>
+      <artifactId>kubernetes-annotations</artifactId>
+      <version>${project.version}</version>
+    </dependency>
+
+So as to add the hostAliases section of the Deployment specification you need pass the `hostAliases` parameter containing the ip address and the list of hostnames (comma separated values) to the `@KubernetesApplication` in the Spring Boot annotated class. The code would look as follow:
+
+```
+@KubernetesApplication(hostAliases = {@HostAlias(ip = "127.0.0.1", hostnames = "foo.org,bar.com")})
+@SpringBootApplication
+public class Main {
+
+  public static void main(String[] args) {
+    SpringApplication.run(Main.class, args);
+  }
+}
+```
+You can pass multiple `@HostAlias` annotation depending of your needs.
+
+Check, if necessary, the [Main.java](src/main/java/io/dekorate/examples/kubernetes/Main.java).
+
+Compile the project using:
+
+    mvn clean install
+
+You can find the generated deployment under: `target/classes/META-INF/dekorate/kubernetes.yml` that should look like:
+```---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  labels:
+    app.kubernetes.io/name: kubernetes-example-with-hostaliases
+    app.kubernetes.io/version: 0.12-SNAPSHOT
+  name: kubernetes-example-with-hostaliases
+spec:
+  replicas: 1
+  template:
+    metadata:
+      labels:
+        app.kubernetes.io/name: kubernetes-example-with-hostaliases
+        app.kubernetes.io/version: 0.12-SNAPSHOT
+    spec:
+      hostAliases:
+      - hostnames:
+        - foo.org
+        - bar.com
+        ip: 127.0.0.1
+      - hostnames:
+        - test.com
+        ip: 10.0.0.1
+```
+
+

examples/kubernetes-example-with-hostaliases/src/main/java/io/dekorate/examples/kubernetes/Controller.java

@@ -0,0 +1,28 @@
+/**
+ * Copyright 2018 The original 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 io.dekorate.examples.kubernetes;
+
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+public class Controller {
+
+  @RequestMapping("/")
+  public String hello() {
+    return "Hello world";
+  }
+}

examples/kubernetes-example-with-hostaliases/src/main/java/io/dekorate/examples/kubernetes/Main.java

@@ -0,0 +1,31 @@
+/**
+ * Copyright 2018 The original 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 io.dekorate.examples.kubernetes;
+
+import io.dekorate.kubernetes.annotation.HostAlias;
+import io.dekorate.kubernetes.annotation.KubernetesApplication;
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@KubernetesApplication(hostAliases = {@HostAlias(ip = "127.0.0.1", hostnames = "foo.org,bar.com"),
+  @HostAlias(ip = "10.0.0.1", hostnames = "test.com")})
+@SpringBootApplication
+public class Main {
+
+  public static void main(String[] args) {
+    SpringApplication.run(Main.class, args);
+  }
+}