Ensure containers are started before binding datasource properties

Update `TestcontainersLifecycleBeanPostProcessor` so that containers
are now initialized either on the first `postProcessAfterInitialization`
call with a frozen configuration or just before a test container
property is supplied.

Prior to this commit, it was assumed that the first post-process call
after the configuration was frozen was suitably early to initialize
the containers. This turns out to not be no always the case.

Specifically, in the `finishBeanFactoryInitialization` method of
`AbstractApplicationContext` we see that `LoadTimeWeaverAware` beans
are obtained before the configuration is frozen. One such bean is
`DefaultPersistenceUnitManager` which is likely to need datasource
properties that will require a started container.

To fix the problem, the `TestcontainersPropertySource` now publishes
a `BeforeTestcontainersPropertySuppliedEvent` to the ApplicationContext
just before any value is supplied. By listening for this event, we can
ensure that containers are initialized and started before any dynamic
property is read.

Fixes gh-38913

spring-boot-project/spring-boot-testcontainers/src/test/java/org/springframework/boot/testcontainers/lifecycle/TestcontainersImportWithPropertiesInjectedIntoLoadTimeWeaverAwareBeanIntegrationTests.java

@@ -0,0 +1,102 @@
+/*
+ * Copyright 2012-2024 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.testcontainers.lifecycle;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.testcontainers.containers.PostgreSQLContainer;
+import org.testcontainers.junit.jupiter.Container;
+
+import org.springframework.boot.context.properties.ConfigurationProperties;
+import org.springframework.boot.context.properties.EnableConfigurationProperties;
+import org.springframework.boot.test.context.TestConfiguration;
+import org.springframework.boot.testcontainers.context.ImportTestcontainers;
+import org.springframework.boot.testcontainers.lifecycle.TestcontainersImportWithPropertiesInjectedIntoLoadTimeWeaverAwareBeanIntegrationTests.Containers;
+import org.springframework.boot.testsupport.testcontainers.DisabledIfDockerUnavailable;
+import org.springframework.boot.testsupport.testcontainers.DockerImageNames;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.weaving.LoadTimeWeaverAware;
+import org.springframework.instrument.classloading.LoadTimeWeaver;
+import org.springframework.test.annotation.DirtiesContext;
+import org.springframework.test.context.DynamicPropertyRegistry;
+import org.springframework.test.context.DynamicPropertySource;
+import org.springframework.test.context.junit.jupiter.SpringExtension;
+
+/**
+ * @author Phillip Webb
+ */
+@ExtendWith(SpringExtension.class)
+@DirtiesContext
+@DisabledIfDockerUnavailable
+@ImportTestcontainers(Containers.class)
+class TestcontainersImportWithPropertiesInjectedIntoLoadTimeWeaverAwareBeanIntegrationTests {
+
+	// gh-38913
+
+	@Test
+	void starts() {
+	}
+
+	@TestConfiguration
+	@EnableConfigurationProperties(MockDataSourceProperties.class)
+	static class Config {
+
+		@Bean
+		MockEntityManager mockEntityManager(MockDataSourceProperties properties) {
+			return new MockEntityManager();
+		}
+
+	}
+
+	static class MockEntityManager implements LoadTimeWeaverAware {
+
+		@Override
+		public void setLoadTimeWeaver(LoadTimeWeaver loadTimeWeaver) {
+		}
+
+	}
+
+	@ConfigurationProperties("spring.datasource")
+	public static class MockDataSourceProperties {
+
+		private String url;
+
+		public String getUrl() {
+			return this.url;
+		}
+
+		public void setUrl(String url) {
+			this.url = url;
+		}
+
+	}
+
+	static class Containers {
+
+		@Container
+		static PostgreSQLContainer<?> container = new PostgreSQLContainer<>(DockerImageNames.postgresql());
+
+		@DynamicPropertySource
+		static void setConnectionProperties(DynamicPropertyRegistry registry) {
+			registry.add("spring.datasource.url", container::getJdbcUrl);
+			registry.add("spring.datasource.password", container::getPassword);
+			registry.add("spring.datasource.username", container::getUsername);
+		}
+
+	}
+
+}

spring-boot-project/spring-boot-testcontainers/src/test/java/org/springframework/boot/testcontainers/properties/TestcontainersPropertySourceAutoConfigurationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -16,6 +16,9 @@
 
 package org.springframework.boot.testcontainers.properties;
 
+import java.util.ArrayList;
+import java.util.List;
+
 import org.junit.jupiter.api.Test;
 
 import org.springframework.boot.autoconfigure.AutoConfigurations;
@@ -25,6 +28,7 @@ import org.springframework.boot.test.context.runner.ApplicationContextRunner;
 import org.springframework.boot.testcontainers.lifecycle.TestcontainersLifecycleApplicationContextInitializer;
 import org.springframework.boot.testsupport.testcontainers.DisabledIfDockerUnavailable;
 import org.springframework.boot.testsupport.testcontainers.RedisContainer;
+import org.springframework.context.ApplicationEvent;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.Import;
@@ -46,11 +50,16 @@ class TestcontainersPropertySourceAutoConfigurationTests {
 
 	@Test
 	void containerBeanMethodContributesProperties() {
-		this.contextRunner.withUserConfiguration(ContainerAndPropertiesConfiguration.class).run((context) -> {
-			TestBean testBean = context.getBean(TestBean.class);
-			RedisContainer redisContainer = context.getBean(RedisContainer.class);
-			assertThat(testBean.getUsingPort()).isEqualTo(redisContainer.getFirstMappedPort());
-		});
+		List<ApplicationEvent> events = new ArrayList<>();
+		this.contextRunner.withUserConfiguration(ContainerAndPropertiesConfiguration.class)
+			.withInitializer((context) -> context.addApplicationListener(events::add))
+			.run((context) -> {
+				TestBean testBean = context.getBean(TestBean.class);
+				RedisContainer redisContainer = context.getBean(RedisContainer.class);
+				assertThat(testBean.getUsingPort()).isEqualTo(redisContainer.getFirstMappedPort());
+				assertThat(events.stream().filter(BeforeTestcontainersPropertySuppliedEvent.class::isInstance))
+					.hasSize(1);
+			});
 	}
 
 	@Configuration(proxyBeanMethods = false)

spring-boot-project/spring-boot-testcontainers/src/test/java/org/springframework/boot/testcontainers/properties/TestcontainersPropertySourceTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -16,10 +16,15 @@
 
 package org.springframework.boot.testcontainers.properties;
 
+import java.util.ArrayList;
+import java.util.List;
 import java.util.Map;
 
 import org.junit.jupiter.api.Test;
 
+import org.springframework.beans.factory.support.BeanDefinitionRegistry;
+import org.springframework.context.ApplicationEvent;
+import org.springframework.context.support.GenericApplicationContext;
 import org.springframework.core.env.EnumerablePropertySource;
 import org.springframework.core.env.PropertySource;
 import org.springframework.mock.env.MockEnvironment;
@@ -101,4 +106,20 @@ class TestcontainersPropertySourceTests {
 		assertThat(p1).isSameAs(p2);
 	}
 
+	@Test
+	void getPropertyPublishesEvent() {
+		try (GenericApplicationContext applicationContext = new GenericApplicationContext()) {
+			List<ApplicationEvent> events = new ArrayList<>();
+			applicationContext.addApplicationListener(events::add);
+			DynamicPropertyRegistry registry = TestcontainersPropertySource.attach(applicationContext.getEnvironment(),
+					(BeanDefinitionRegistry) applicationContext.getBeanFactory());
+			applicationContext.refresh();
+			registry.add("test", () -> "spring");
+			assertThat(applicationContext.getEnvironment().containsProperty("test")).isTrue();
+			assertThat(events.isEmpty());
+			assertThat(applicationContext.getEnvironment().getProperty("test")).isEqualTo("spring");
+			assertThat(events.stream().filter(BeforeTestcontainersPropertySuppliedEvent.class::isInstance)).hasSize(1);
+		}
+	}
+
 }