Allow testcontainer beans to also contribute properties

Allow `Container` bean definitions to inject a `DynamicPropertyRegistry`
so that they can contribute environment properties.

Closes gh-35201

spring-boot-project/spring-boot-testcontainers/src/main/java/org/springframework/boot/testcontainers/properties/TestcontainersPropertySource.java

@@ -0,0 +1,93 @@
+/*
+ * Copyright 2012-2023 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.properties;
+
+import java.util.Collections;
+import java.util.LinkedHashMap;
+import java.util.Map;
+import java.util.function.Supplier;
+
+import org.testcontainers.containers.Container;
+
+import org.springframework.core.env.ConfigurableEnvironment;
+import org.springframework.core.env.EnumerablePropertySource;
+import org.springframework.core.env.Environment;
+import org.springframework.core.env.PropertySource;
+import org.springframework.test.context.DynamicPropertyRegistry;
+import org.springframework.util.Assert;
+import org.springframework.util.StringUtils;
+
+/**
+ * {@link EnumerablePropertySource} backed by a map with values supplied from one or more
+ * {@link Container testcontainers}.
+ *
+ * @author Phillip Webb
+ * @since 3.1.0
+ */
+public class TestcontainersPropertySource extends EnumerablePropertySource<Map<String, Supplier<Object>>> {
+
+	static final String NAME = "testcontainersPropertySource";
+
+	private final DynamicPropertyRegistry registry;
+
+	TestcontainersPropertySource() {
+		this(Collections.synchronizedMap(new LinkedHashMap<>()));
+	}
+
+	private TestcontainersPropertySource(Map<String, Supplier<Object>> valueSuppliers) {
+		super(NAME, Collections.unmodifiableMap(valueSuppliers));
+		this.registry = (name, valueSupplier) -> {
+			Assert.hasText(name, "'name' must not be null or blank");
+			Assert.notNull(valueSupplier, "'valueSupplier' must not be null");
+			valueSuppliers.put(name, valueSupplier);
+		};
+	}
+
+	@Override
+	public Object getProperty(String name) {
+		Supplier<Object> valueSupplier = this.source.get(name);
+		return (valueSupplier != null) ? valueSupplier.get() : null;
+	}
+
+	@Override
+	public boolean containsProperty(String name) {
+		return this.source.containsKey(name);
+	}
+
+	@Override
+	public String[] getPropertyNames() {
+		return StringUtils.toStringArray(this.source.keySet());
+	}
+
+	public static DynamicPropertyRegistry attach(Environment environment) {
+		Assert.state(environment instanceof ConfigurableEnvironment,
+				"TestcontainersPropertySource can only be attached to a ConfigurableEnvironment");
+		return attach((ConfigurableEnvironment) environment);
+	}
+
+	private static DynamicPropertyRegistry attach(ConfigurableEnvironment environment) {
+		PropertySource<?> propertySource = environment.getPropertySources().get(NAME);
+		if (propertySource == null) {
+			environment.getPropertySources().addFirst(new TestcontainersPropertySource());
+			return attach(environment);
+		}
+		Assert.state(propertySource instanceof TestcontainersPropertySource,
+				"Incorrect DynamicValuesPropertySource type registered");
+		return ((TestcontainersPropertySource) propertySource).registry;
+	}
+
+}

spring-boot-project/spring-boot-testcontainers/src/main/java/org/springframework/boot/testcontainers/properties/TestcontainersPropertySourceAutoConfiguration.java

@@ -0,0 +1,42 @@
+/*
+ * Copyright 2012-2023 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.properties;
+
+import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
+import org.springframework.context.annotation.Bean;
+import org.springframework.core.env.ConfigurableEnvironment;
+import org.springframework.test.context.DynamicPropertyRegistry;
+
+/**
+ * {@link org.springframework.boot.autoconfigure.EnableAutoConfiguration
+ * Auto-configuration} to add {@link TestcontainersPropertySource} support.
+ *
+ * @author Phillip Webb
+ * @since 3.1.0
+ */
+@ConditionalOnClass(DynamicPropertyRegistry.class)
+public class TestcontainersPropertySourceAutoConfiguration {
+
+	TestcontainersPropertySourceAutoConfiguration() {
+	}
+
+	@Bean
+	DynamicPropertyRegistry dynamicPropertyRegistry(ConfigurableEnvironment environment) {
+		return TestcontainersPropertySource.attach(environment);
+	}
+
+}

spring-boot-project/spring-boot-testcontainers/src/main/java/org/springframework/boot/testcontainers/properties/package-info.java

@@ -0,0 +1,20 @@
+/*
+ * Copyright 2012-2023 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.
+ */
+
+/**
+ * Dynamic container properties support.
+ */
+package org.springframework.boot.testcontainers.properties;

spring-boot-project/spring-boot-testcontainers/src/main/resources/META-INF/spring/org.springframework.boot.autoconfigure.AutoConfiguration.imports

@@ -1 +1,2 @@
+org.springframework.boot.testcontainers.properties.DynamicProperySourceAutoConfiguration
 org.springframework.boot.testcontainers.service.connection.ServiceConnectionAutoConfiguration