LeaderAutoConfiguration and LeaderProperties

spring-cloud-kubernetes-leader/src/main/java/org/springframework/cloud/kubernetes/leader/LeaderAutoConfiguration.java

@@ -0,0 +1,50 @@
+/*
+ * Copyright 2018 Red Hat, Inc, and individual contributors.
+ *
+ * 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 org.springframework.cloud.kubernetes.leader;
+
+import java.net.Inet4Address;
+import java.net.UnknownHostException;
+
+import io.fabric8.kubernetes.client.KubernetesClient;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
+import org.springframework.boot.context.properties.EnableConfigurationProperties;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.integration.leader.Candidate;
+import org.springframework.integration.leader.DefaultCandidate;
+
+/**
+ * @author <a href="mailto:gytis@redhat.com">Gytis Trikleris</a>
+ */
+@Configuration
+@EnableConfigurationProperties(LeaderProperties.class)
+@ConditionalOnBean(KubernetesClient.class)
+@ConditionalOnProperty(value = "spring.cloud.kubernetes.leader.enabled", matchIfMissing = true)
+public class LeaderAutoConfiguration {
+
+	@Bean
+	public LeaderInitiator leaderInitiator(KubernetesClient kubernetesClient, LeaderProperties leaderProperties)
+		throws UnknownHostException {
+		String candidateId = Inet4Address.getLocalHost().getHostName();
+		Candidate candidate = new DefaultCandidate(candidateId, leaderProperties.getRole());
+		LeaderInitiator leaderInitiator = new LeaderInitiator(kubernetesClient, candidate, leaderProperties);
+		leaderInitiator.start();
+		return leaderInitiator;
+	}
+
+}

spring-cloud-kubernetes-leader/src/main/java/org/springframework/cloud/kubernetes/leader/LeaderInitiator.java

@@ -42,22 +42,21 @@ public class LeaderInitiator implements SmartLifecycle {
 
 	private final Candidate candidate;
 
-	private final LeaderConfiguration leaderConfiguration;
+	private final LeaderProperties leaderProperties;
 
 	private ScheduledExecutorService scheduledExecutorService;
 
 	private String currentLeaderId; // TODO remove once events are implemented
 
-	public LeaderInitiator(KubernetesClient kubernetesClient, Candidate candidate,
-		LeaderConfiguration leaderConfiguration) {
+	public LeaderInitiator(KubernetesClient kubernetesClient, Candidate candidate, LeaderProperties leaderProperties) {
 		this.kubernetesClient = kubernetesClient;
 		this.candidate = candidate;
-		this.leaderConfiguration = leaderConfiguration;
+		this.leaderProperties = leaderProperties;
 	}
 
 	@Override
 	public boolean isAutoStartup() {
-		return leaderConfiguration.isAutoStartup();
+		return leaderProperties.isAutoStartup();
 	}
 
 	@Override
@@ -115,40 +114,40 @@ public class LeaderInitiator implements SmartLifecycle {
 			try {
 				takeLeadership(configMap);
 				currentLeaderId = candidate.getId();
-				scheduleUpdate(leaderConfiguration.getLeaseDuration());
+				scheduleUpdate(leaderProperties.getLeaseDuration());
 			} catch (Exception e) {
 				// Leadership takeover failed, try again later
 				System.out.println("Leadership takeover failed: " + e.getMessage());
-				scheduleUpdate(leaderConfiguration.getRetryPeriod());
+				scheduleUpdate(leaderProperties.getRetryPeriod());
 			}
 		} else if (!isValidLeader(leader)) {
 			System.out.println("Old leader is not valid any more, try to take over");
 			try {
 				takeLeadership(configMap);
 				currentLeaderId = candidate.getId();
-				scheduleUpdate(leaderConfiguration.getLeaseDuration()); // Is this needed?
+				scheduleUpdate(leaderProperties.getLeaseDuration()); // Is this needed?
 			} catch (Exception e) {
 				// Leadership takeover failed, try again later
 				System.out.println("Leadership takeover failed: " + e.getMessage());
-				scheduleUpdate(leaderConfiguration.getRetryPeriod());
+				scheduleUpdate(leaderProperties.getRetryPeriod());
 			}
 		} else if (!isCandidateALeader(leader)) {
 			currentLeaderId = leader.getId();
 			System.out.println(currentLeaderId + " is a leader, check in later");
-			scheduleUpdate(leaderConfiguration.getLeaseDuration());
+			scheduleUpdate(leaderProperties.getLeaseDuration());
 		} else {
 			System.out.println("I am a leader, check in later");
 			currentLeaderId = candidate.getId();
-			scheduleUpdate(leaderConfiguration.getLeaseDuration()); // Is this needed?
+			scheduleUpdate(leaderProperties.getLeaseDuration()); // Is this needed?
 		}
 	}
 
 	private void takeLeadership(ConfigMap oldConfigMap) {
-		String leaderIdKey = leaderConfiguration.getLeaderIdPrefix() + candidate.getRole();
+		String leaderIdKey = leaderProperties.getLeaderIdPrefix() + candidate.getRole();
 
 		if (oldConfigMap == null) {
 			ConfigMap newConfigMap = new ConfigMapBuilder().withNewMetadata()
-				.withName(leaderConfiguration.getConfigMapName())
+				.withName(leaderProperties.getConfigMapName())
 				.addToLabels("provider", "spring-cloud-kubernetes")
 				.addToLabels("kind", "locks")
 				.endMetadata()
@@ -156,7 +155,7 @@ public class LeaderInitiator implements SmartLifecycle {
 				.build();
 
 			kubernetesClient.configMaps()
-				.inNamespace(leaderConfiguration.getNamespace(kubernetesClient.getNamespace()))
+				.inNamespace(leaderProperties.getNamespace(kubernetesClient.getNamespace()))
 				.create(newConfigMap);
 		} else {
 			ConfigMap newConfigMap = new ConfigMapBuilder(oldConfigMap)
@@ -164,8 +163,8 @@ public class LeaderInitiator implements SmartLifecycle {
 				.build();
 
 			kubernetesClient.configMaps()
-				.inNamespace(leaderConfiguration.getNamespace(kubernetesClient.getNamespace()))
-				.withName(leaderConfiguration.getConfigMapName())
+				.inNamespace(leaderProperties.getNamespace(kubernetesClient.getNamespace()))
+				.withName(leaderProperties.getConfigMapName())
 				.lockResourceVersion(oldConfigMap.getMetadata().getResourceVersion())
 				.replace(newConfigMap);
 		}
@@ -176,8 +175,8 @@ public class LeaderInitiator implements SmartLifecycle {
 	private ConfigMap getConfigMap() {
 		try {
 			return kubernetesClient.configMaps()
-				.inNamespace(leaderConfiguration.getNamespace(kubernetesClient.getNamespace()))
-				.withName(leaderConfiguration.getConfigMapName())
+				.inNamespace(leaderProperties.getNamespace(kubernetesClient.getNamespace()))
+				.withName(leaderProperties.getConfigMapName())
 				.get();
 		} catch (Exception e) {
 			System.out.println("Failed to get a ConfigMap: " + e.getMessage());
@@ -191,7 +190,7 @@ public class LeaderInitiator implements SmartLifecycle {
 		}
 
 		Map<String, String> data = configMap.getData();
-		String leaderIdKey = leaderConfiguration.getLeaderIdPrefix() + candidate.getRole();
+		String leaderIdKey = leaderProperties.getLeaderIdPrefix() + candidate.getRole();
 		String leaderId = data.get(leaderIdKey);
 		if (leaderId == null) {
 			return null;
@@ -205,7 +204,7 @@ public class LeaderInitiator implements SmartLifecycle {
 	}
 
 	private long jitter(long num) {
-		return (long) (num * (1 + Math.random() * (leaderConfiguration.getJitterFactor() - 1)));
+		return (long) (num * (1 + Math.random() * (leaderProperties.getJitterFactor() - 1)));
 	}
 
 	private boolean isCandidateALeader(Leader leader) {
@@ -214,8 +213,8 @@ public class LeaderInitiator implements SmartLifecycle {
 
 	private boolean isValidLeader(Leader leader) {
 		return kubernetesClient.pods()
-			.inNamespace(leaderConfiguration.getNamespace(kubernetesClient.getNamespace()))
-			.withLabels(leaderConfiguration.getLabels())
+			.inNamespace(leaderProperties.getNamespace(kubernetesClient.getNamespace()))
+			.withLabels(leaderProperties.getLabels())
 			.list()
 			.getItems()
 			.stream()

spring-cloud-kubernetes-leader/src/main/java/org/springframework/cloud/kubernetes/leader/LeaderProperties.java

@@ -19,10 +19,13 @@ package org.springframework.cloud.kubernetes.leader;
 import java.util.Collections;
 import java.util.Map;
 
+import org.springframework.boot.context.properties.ConfigurationProperties;
+
 /**
  * @author <a href="mailto:gytis@redhat.com">Gytis Trikleris</a>
  */
-public class LeaderConfiguration {
+@ConfigurationProperties("spring.cloud.kubernetes.leader")
+public class LeaderProperties {
 
 	private static final String DEFAULT_LEADER_ID_PREFIX = "leader.id.";
 
@@ -36,20 +39,56 @@ public class LeaderConfiguration {
 
 	private static final double DEFAULT_JITTER_FACTOR = 1.2;
 
+	/**
+	 * Should leader election be started automatically on startup.
+	 * Default: true
+	 */
 	private boolean autoStartup = DEFAULT_AUTO_STARTUP;
 
+	/**
+	 * Role for which leadership this candidate will compete.
+	 */
+	private String role;
+
+	/**
+	 * Kubernetes namespace where the leaders ConfigMap and candidates are located.
+	 */
 	private String namespace;
 
+	/**
+	 * Kubernetes ConfigMap where leaders information will be stored.
+	 * Default: leaders
+	 */
 	private String configMapName = DEFAULT_CONFIG_MAP_NAME;
 
+	/**
+	 * Kubernetes labels common to all leadership candidates.
+	 * Default: empty
+	 */
 	private Map<String, String> labels = Collections.emptyMap();
 
+	/**
+	 * Leader id property prefix for the ConfigMap.
+	 * Default: leader.id.
+	 */
 	private String leaderIdPrefix = DEFAULT_LEADER_ID_PREFIX;
 
+	/**
+	 * Time period after which leader should check it's leadership or new leader should be elected.
+	 * Default: 30s
+	 */
 	private long leaseDuration = DEFAULT_LEASE_DURATION;
 
+	/**
+	 * Time period after connections should be retired after failure.
+	 * Default: 5s
+	 */
 	private long retryPeriod = DEFAULT_RETRY_PERIOD;
 
+	/**
+	 * A parameter to randomise scheduler.
+	 * Default: 1.2
+	 */
 	private double jitterFactor = DEFAULT_JITTER_FACTOR;
 
 	public boolean isAutoStartup() {
@@ -60,6 +99,14 @@ public class LeaderConfiguration {
 		this.autoStartup = autoStartup;
 	}
 
+	public String getRole() {
+		return role;
+	}
+
+	public void setRole(String role) {
+		this.role = role;
+	}
+
 	public String getNamespace() {
 		return namespace;
 	}

spring-cloud-kubernetes-leader/src/main/resources/META-INF/spring.factories

@@ -0,0 +1,2 @@
+org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
+org.springframework.cloud.kubernetes.leader.LeaderAutoConfiguration