LeadershipController#getLeader

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

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+/*
+ * 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.util.Map;
+
+import io.fabric8.kubernetes.api.model.ConfigMap;
+import io.fabric8.kubernetes.client.KubernetesClient;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.integration.leader.Candidate;
+
+/**
+ * @author <a href="mailto:gytis@redhat.com">Gytis Trikleris</a>
+ */
+public class LeadershipController {
+
+	private static final Logger LOGGER = LoggerFactory.getLogger(LeadershipController.class);
+
+	private final LeaderProperties leaderProperties;
+
+	private final KubernetesClient kubernetesClient;
+
+	public LeadershipController(LeaderProperties leaderProperties, KubernetesClient kubernetesClient) {
+		this.leaderProperties = leaderProperties;
+		this.kubernetesClient = kubernetesClient;
+	}
+
+	public boolean acquire(Candidate candidate) {
+		return false;
+	}
+
+	public boolean revoke(Candidate candidate) {
+		return false;
+	}
+
+	public Leader getLeader(String role) {
+		ConfigMap configMap = getConfigMap();
+		if (configMap == null || configMap.getData() == null) {
+			return null;
+		}
+
+		Map<String, String> data = configMap.getData();
+		String leaderIdKey = leaderProperties.getLeaderIdPrefix() + role;
+		String leaderId = data.get(leaderIdKey);
+		if (leaderId == null) {
+			return null;
+		}
+
+		return new Leader(role, leaderId);
+	}
+
+	private ConfigMap getConfigMap() {
+		String namespace = leaderProperties.getNamespace(kubernetesClient.getNamespace());
+		String name = leaderProperties.getConfigMapName();
+		try {
+			return kubernetesClient.configMaps()
+				.inNamespace(namespace)
+				.withName(name)
+				.get();
+		} catch (Exception e) {
+			LOGGER.warn("Failed to get ConfigMap '{}' in the namespace '{}': {}", namespace, name, e.getMessage());
+			return null;
+		}
+	}
+
+}

spring-cloud-kubernetes-leader/src/test/java/org/springframework/cloud/kubernetes/leader/LeadershipControllerTest.java

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+package org.springframework.cloud.kubernetes.leader;
+
+import java.util.Map;
+
+import io.fabric8.kubernetes.api.model.ConfigMap;
+import io.fabric8.kubernetes.api.model.ConfigMapList;
+import io.fabric8.kubernetes.api.model.DoneableConfigMap;
+import io.fabric8.kubernetes.client.KubernetesClient;
+import io.fabric8.kubernetes.client.dsl.MixedOperation;
+import io.fabric8.kubernetes.client.dsl.NonNamespaceOperation;
+import io.fabric8.kubernetes.client.dsl.Resource;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.junit.MockitoJUnitRunner;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.BDDMockito.given;
+
+/**
+ * @author <a href="mailto:gytis@redhat.com">Gytis Trikleris</a>
+ */
+@RunWith(MockitoJUnitRunner.class)
+public class LeadershipControllerTest {
+
+	private final String NAMESPACE = "test-namespace";
+
+	private final String CONFIG_MAP_NAME = "test-config-map-name";
+
+	private final String ROLE = "test-role";
+
+	private final String ID = "test-id";
+
+	@Mock
+	private LeaderProperties mockLeaderProperties;
+
+	@Mock
+	private KubernetesClient mockKubernetesClient;
+
+	@Mock
+	private MixedOperation<ConfigMap, ConfigMapList, DoneableConfigMap, Resource<ConfigMap, DoneableConfigMap>> configMapsOperation;
+
+	@Mock
+	private NonNamespaceOperation<ConfigMap, ConfigMapList, DoneableConfigMap, Resource<ConfigMap, DoneableConfigMap>> inNamespaceOperation;
+
+	@Mock
+	private Resource<ConfigMap, DoneableConfigMap> configMapResource;
+
+	@Mock
+	private ConfigMap mockConfigMap;
+
+	@Mock
+	private Map<String, String> mockData;
+
+	private LeadershipController leadershipController;
+
+	@Before
+	public void before() {
+		given(mockLeaderProperties.getLeaderIdPrefix()).willReturn("");
+		given(mockLeaderProperties.getNamespace(NAMESPACE)).willReturn(NAMESPACE);
+		given(mockLeaderProperties.getConfigMapName()).willReturn(CONFIG_MAP_NAME);
+
+		given(mockKubernetesClient.getNamespace()).willReturn(NAMESPACE);
+		given(mockKubernetesClient.configMaps()).willReturn(configMapsOperation);
+		given(configMapsOperation.inNamespace(NAMESPACE)).willReturn(inNamespaceOperation);
+		given(inNamespaceOperation.withName(CONFIG_MAP_NAME)).willReturn(configMapResource);
+		given(configMapResource.get()).willReturn(mockConfigMap);
+		given(mockConfigMap.getData()).willReturn(mockData);
+		given(mockData.get(ROLE)).willReturn(ID);
+
+		leadershipController = new LeadershipController(mockLeaderProperties, mockKubernetesClient);
+	}
+
+	@Test
+	public void shouldGetLeader() {
+		Leader leader = leadershipController.getLeader(ROLE);
+		assertThat(leader.getRole()).isEqualTo(ROLE);
+		assertThat(leader.getId()).isEqualTo(ID);
+	}
+
+	@Test
+	public void shouldNotGetLeaderFromNonExistingConfigMap() {
+		given(mockLeaderProperties.getConfigMapName()).willReturn("unknown");
+
+		Leader leader = leadershipController.getLeader(ROLE);
+		assertThat(leader).isNull();
+	}
+
+	@Test
+	public void shouldNotGetLeaderFromEmptyConfigMap() {
+		given(mockConfigMap.getData()).willReturn(null);
+
+		Leader leader = leadershipController.getLeader(ROLE);
+		assertThat(leader).isNull();
+	}
+
+	@Test
+	public void shouldNotGetLeaderFromInvalidConfigMap() {
+		given(mockData.get(ROLE)).willReturn(null);
+
+		Leader leader = leadershipController.getLeader(ROLE);
+		assertThat(leader).isNull();
+	}
+
+	@Test
+	public void shouldHandleFailureWhenGettingLeader() {
+		given(mockKubernetesClient.configMaps()).willThrow(new RuntimeException("Test exception"));
+
+		Leader leader = leadershipController.getLeader(ROLE);
+		assertThat(leader).isNull();
+	}
+
+}