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Merge pull request #256 from java-operator-sdk/tomcat-sample
update Tomcat sample to use EventSources
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‎samples/tomcat/README.md

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Creates a Tomcat deployment from a Custom Resource, while keeping the WAR separated with another Custom Resource.
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This sample demonstrates the following capabilities of the Java Operator SDK:
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* Multiple Controllers in a single Operator. The Tomcat resource is managed by the TomcatController while the Webapp
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resource is managed by the WebappController.
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* Reacting to events about resources created by the controller. The TomcatController will receive events about the
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Deployment resources it created. See EventSource section below for more detail.
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## Example input for creating a Tomcat instance
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```
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apiVersion: "tomcatoperator.io/v1"
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## Getting started / Testing
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The quickest way to try the operator is to run it on your local machine, while it connects to a local or remote Kubernetes cluster. When you start it it will use the current kubectl context on your machine to connect to the cluster.
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The quickest way to try the operator is to run it on your local machine, while it connects to a local or remote
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Kubernetes cluster. When you start it, it will use the current kubectl context on your machine to connect to the cluster.
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Before you run it you have to install the CRD on your cluster by running `kubectl apply -f k8s/crd.yaml`.
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When the Operator is running you can create some Tomcat Custom Resources. You can find a sample custom resources in the k8s folder.
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When the Operator is running you can create some Tomcat Custom Resources. You can find a sample custom resources
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in the k8s folder.
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If you want the Operator to be running as a deployment in your cluster, follow the below steps.
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## Build
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You can build the sample using `mvn install jib:dockerBuild` this will produce a Docker image you can push to the registry of your choice. The jar file is built using your local Maven and JDK and then copied into the Docker image.
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You can build the sample using `mvn install jib:dockerBuild` this will produce a Docker image you can push to the
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registry of your choice. The jar file is built using your local Maven and JDK and then copied into the Docker image.
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## Install Operator into cluster
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Run `kubectl apply -f k8s/crd.yaml` if you haven't already, then run `kubectl apply -f k8s/operator.yaml`.
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Now you can create Tomcat instances with CRs (see examples above).
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## EventSources
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The TomcatController is listening to events about Deployments created by the TomcatOperator by registering a
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DeploymentEventSource with the EventSourceManager. The DeploymentEventSource will in turn register a watch on
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all Deployments managed by the Controller (identified by the `managed-by` label).
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When an event from a Deployment is received we have to identify which Tomcat object does the Deployment
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belong to. This is done when the DeploymentEventSource creates the DeploymentEvent.
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## Install Operator into cluster
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The TomcatController has to take care of setting the `managed-by` label on the Deployment so the
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DeploymentEventSource can watch the right Deployments.
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The TomcatController also has to set `ownerReference` on the Deployment so later the DeploymentEventSource can
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identify which Tomcat does the Deployment belong to. This is necessary so the frameowork can call the Controller
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`createOrUpdate` method correctly.
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Run `kubectl apply -f k8s/crd.yaml` if you haven't already, then run `kubectl apply -f k8s/operator.yaml`. Now you can create Tomcat instances with CRs (see examples above).

‎samples/tomcat/pom.xml

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<artifactId>tomcat-sample</artifactId>
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<name>Operator SDK - Samples - Tomcat</name>
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<description>Provisions a Tomcat server based on CRDs</description>
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<description>Provisions Tomcat Pods and deploys Webapplications in them</description>
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<packaging>jar</packaging>
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<properties>
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<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
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<java-operator-sdk.version>1.3.0</java-operator-sdk.version>
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<java.version>11</java.version>
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<maven.compiler.source>11</maven.compiler.source>
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<maven.compiler.target>11</maven.compiler.target>
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<jib-maven-plugin.version>2.5.2</jib-maven-plugin.version>
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<dependency>
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<groupId>commons-io</groupId>
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<artifactId>commons-io</artifactId>
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<version>2.8.0</version>
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</dependency>
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<dependency>
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<groupId>io.fabric8</groupId>
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<artifactId>kubernetes-client</artifactId>
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<version>4.12.0</version>
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<version>2.6</version>
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</dependency>
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</dependencies>
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<build>
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<plugins>
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<plugin>
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<groupId>org.apache.maven.plugins</groupId>
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<artifactId>maven-compiler-plugin</artifactId>
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<version>3.8.1</version>
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</plugin>
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<plugin>
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<groupId>com.spotify</groupId>
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<artifactId>dockerfile-maven-plugin</artifactId>
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<version>1.4.13</version>
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<groupId>com.google.cloud.tools</groupId>
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<artifactId>jib-maven-plugin</artifactId>
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<version>${jib-maven-plugin.version}</version>
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<configuration>
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<repository>tomcat-operator</repository>
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<tag>latest</tag>
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<buildArgs>
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<JAR_FILE>${project.build.finalName}.jar</JAR_FILE>
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</buildArgs>
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<from>
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<image>gcr.io/distroless/java:11</image>
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</from>
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<to>
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<image>eu.gcr.io/adamsandor-test/tomcat-operator</image>
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</to>
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</configuration>
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</plugin>
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<plugin>
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<groupId>org.apache.maven.plugins</groupId>
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<artifactId>maven-shade-plugin</artifactId>
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<version>3.2.4</version>
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<executions>
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<execution>
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<phase>package</phase>
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<goals>
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<goal>shade</goal>
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</goals>
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<configuration>
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<createDependencyReducedPom>false</createDependencyReducedPom>
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<transformers>
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<transformer implementation="org.apache.maven.plugins.shade.resource.ServicesResourceTransformer" />
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<transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
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<manifestEntries>
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<Main-Class>io.javaoperatorsdk.operator.sample.TomcatOperator</Main-Class>
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<Build-Number>1.0</Build-Number>
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<Multi-Release>true</Multi-Release>
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</manifestEntries>
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</transformer>
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</transformers>
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<filters>
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<filter>
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<artifact>io.fabric8:openshift-client</artifact>
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<excludes>
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<exclude>io/fabric8/kubernetes/client/Config*</exclude>
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</excludes>
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</filter>
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</filters>
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</configuration>
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</execution>
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</executions>
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<artifactId>maven-compiler-plugin</artifactId>
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<version>3.8.1</version>
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</plugin>
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</plugins>
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</build>
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</project>
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</project>

‎samples/tomcat/src/main/java/META-INF/MANIFEST.MF

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This file was deleted.

‎samples/tomcat/src/main/java/io/javaoperatorsdk/operator/sample/DeploymentEvent.java

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package io.javaoperatorsdk.operator.sample;
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import io.fabric8.kubernetes.api.model.apps.Deployment;
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import io.fabric8.kubernetes.client.Watcher;
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import io.javaoperatorsdk.operator.processing.event.AbstractEvent;
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public class DeploymentEvent extends AbstractEvent {
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private final Watcher.Action action;
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private final Deployment deployment;
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public DeploymentEvent(
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Watcher.Action action, Deployment resource, DeploymentEventSource deploymentEventSource) {
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// TODO: this mapping is really critical and should be made more explicit
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super(resource.getMetadata().getOwnerReferences().get(0).getUid(), deploymentEventSource);
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this.action = action;
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this.deployment = resource;
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}
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public Watcher.Action getAction() {
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return action;
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}
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public String resourceUid() {
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return getDeployment().getMetadata().getUid();
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}
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@Override
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public String toString() {
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return "CustomResourceEvent{"
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+ "action="
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+ action
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+ ", resource=[ name="
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+ getDeployment().getMetadata().getName()
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+ ", kind="
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+ getDeployment().getKind()
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+ ", apiVersion="
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+ getDeployment().getApiVersion()
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+ " ,resourceVersion="
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+ getDeployment().getMetadata().getResourceVersion()
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+ ", markedForDeletion: "
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+ (getDeployment().getMetadata().getDeletionTimestamp() != null
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&& !getDeployment().getMetadata().getDeletionTimestamp().isEmpty())
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+ " ]"
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+ '}';
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}
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public Deployment getDeployment() {
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return deployment;
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}
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}

‎samples/tomcat/src/main/java/io/javaoperatorsdk/operator/sample/DeploymentEventSource.java

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package io.javaoperatorsdk.operator.sample;
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import static io.javaoperatorsdk.operator.processing.KubernetesResourceUtils.getUID;
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import static io.javaoperatorsdk.operator.processing.KubernetesResourceUtils.getVersion;
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import static java.net.HttpURLConnection.HTTP_GONE;
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import io.fabric8.kubernetes.api.model.apps.Deployment;
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import io.fabric8.kubernetes.client.KubernetesClient;
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import io.fabric8.kubernetes.client.KubernetesClientException;
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import io.fabric8.kubernetes.client.Watcher;
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import io.javaoperatorsdk.operator.processing.event.AbstractEventSource;
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import org.slf4j.Logger;
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import org.slf4j.LoggerFactory;
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public class DeploymentEventSource extends AbstractEventSource implements Watcher<Deployment> {
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private static final Logger log = LoggerFactory.getLogger(DeploymentEventSource.class);
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private final KubernetesClient client;
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public static DeploymentEventSource createAndRegisterWatch(KubernetesClient client) {
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DeploymentEventSource deploymentEventSource = new DeploymentEventSource(client);
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deploymentEventSource.registerWatch();
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return deploymentEventSource;
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}
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private DeploymentEventSource(KubernetesClient client) {
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this.client = client;
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}
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private void registerWatch() {
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client
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.apps()
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.deployments()
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.inAnyNamespace()
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.withLabel("managed-by", "tomcat-operator")
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.watch(this);
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}
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@Override
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public void eventReceived(Action action, Deployment deployment) {
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log.info(
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"Event received for action: {}, Deployment: {} (rr={})",
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action.name(),
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deployment.getMetadata().getName(),
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deployment.getStatus().getReadyReplicas());
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if (action == Action.ERROR) {
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log.warn(
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"Skipping {} event for custom resource uid: {}, version: {}",
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action,
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getUID(deployment),
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getVersion(deployment));
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return;
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}
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eventHandler.handleEvent(new DeploymentEvent(action, deployment, this));
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}
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@Override
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public void onClose(KubernetesClientException e) {
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if (e == null) {
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return;
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}
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if (e.getCode() == HTTP_GONE) {
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log.warn("Received error for watch, will try to reconnect.", e);
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registerWatch();
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} else {
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// Note that this should not happen normally, since fabric8 client handles reconnect.
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// In case it tries to reconnect this method is not called.
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log.error("Unexpected error happened with watch. Will exit.", e);
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System.exit(1);
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}
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}
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}

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