Prevent autoconfigure of ApplicationAvailability when already registered

Signed-off-by: Taeik Lim <[email protected]>

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/availability/ApplicationAvailabilityAutoConfiguration.java

@@ -17,6 +17,8 @@
 package org.springframework.boot.autoconfigure.availability;
 
 import org.springframework.boot.autoconfigure.AutoConfiguration;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
+import org.springframework.boot.availability.ApplicationAvailability;
 import org.springframework.boot.availability.ApplicationAvailabilityBean;
 import org.springframework.context.annotation.Bean;
 
@@ -25,13 +27,15 @@
  * {@link ApplicationAvailabilityBean}.
  *
  * @author Brian Clozel
+ * @author Taeik Lim
  * @since 2.3.0
  */
 @AutoConfiguration
 public class ApplicationAvailabilityAutoConfiguration {
 
 	@Bean
-	public ApplicationAvailabilityBean applicationAvailability() {
+	@ConditionalOnMissingBean(ApplicationAvailability.class)
+	public ApplicationAvailability applicationAvailability() {
 		return new ApplicationAvailabilityBean();
 	}
 

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/availability/ApplicationAvailabilityAutoConfigurationTests.java

@@ -0,0 +1,82 @@
+/*
+ * Copyright 2012-2020 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
+ *
+ *      https://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.boot.autoconfigure.availability;
+
+import org.junit.jupiter.api.Test;
+
+import org.springframework.boot.autoconfigure.AutoConfigurations;
+import org.springframework.boot.availability.ApplicationAvailability;
+import org.springframework.boot.availability.AvailabilityChangeEvent;
+import org.springframework.boot.availability.AvailabilityState;
+import org.springframework.boot.test.context.runner.ApplicationContextRunner;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Tests for {@link ApplicationAvailabilityAutoConfiguration}
+ *
+ * @author Brian Clozel
+ * @author Taeik Lim
+ */
+class ApplicationAvailabilityAutoConfigurationTests {
+
+	private final ApplicationContextRunner contextRunner = new ApplicationContextRunner()
+			.withConfiguration(AutoConfigurations.of(ApplicationAvailabilityAutoConfiguration.class));
+
+	@Test
+	void providerIsPresentWhenNotRegistered() {
+		this.contextRunner.run(((context) -> assertThat(context)
+				.hasSingleBean(ApplicationAvailability.class)
+				.hasBean("applicationAvailability")
+		));
+	}
+
+	@Test
+	void providerIsPresentWithRegisteredOne() {
+		this.contextRunner.withUserConfiguration(ApplicationAvailabilityConfig.class)
+				.run(((context) -> assertThat(context)
+						.hasSingleBean(ApplicationAvailability.class)
+						.hasBean("customApplicationAvailability")
+				));
+	}
+
+	@Configuration(proxyBeanMethods = false)
+	static class ApplicationAvailabilityConfig {
+
+		@Bean
+		ApplicationAvailability customApplicationAvailability() {
+			return new ApplicationAvailability() {
+				@Override
+				public <S extends AvailabilityState> S getState(Class<S> stateType, S defaultState) {
+					return null;
+				}
+
+				@Override
+				public <S extends AvailabilityState> S getState(Class<S> stateType) {
+					return null;
+				}
+
+				@Override
+				public <S extends AvailabilityState> AvailabilityChangeEvent<S> getLastChangeEvent(Class<S> stateType) {
+					return null;
+				}
+			};
+		}
+	}
+}