Inherit Environment from main context when creating a Binder

The DefaultBinderFactory makes use of SpringApplicationBuilder to
build a context containing a binder. It has access to the Environment
of the surrounding context, but doesn't use it, and doesn't use it
(before this change). Users will be surprised if (for instance) they
change the default rabbitmq hostname and the change doesn't propagate
to the binder.

spring-cloud-stream/src/main/java/org/springframework/cloud/stream/binder/DefaultBinderFactory.java

@@ -26,7 +26,9 @@ import org.springframework.boot.Banner.Mode;
 import org.springframework.boot.builder.SpringApplicationBuilder;
 import org.springframework.context.ConfigurableApplicationContext;
 import org.springframework.context.EnvironmentAware;
+import org.springframework.core.env.ConfigurableEnvironment;
 import org.springframework.core.env.Environment;
+import org.springframework.core.env.StandardEnvironment;
 import org.springframework.util.StringUtils;
 
 /**
@@ -59,7 +61,7 @@ public class DefaultBinderFactory<T> implements BinderFactory<T>, DisposableBean
 
 	@Override
 	public void destroy() throws Exception {
-		for (Map.Entry<String, BinderInstanceHolder<T>> entry : binderInstanceCache.entrySet()) {
+		for (Map.Entry<String, BinderInstanceHolder<T>> entry : this.binderInstanceCache.entrySet()) {
 			BinderInstanceHolder<T> binderInstanceHolder = entry.getValue();
 			binderInstanceHolder.getBinderContext().close();
 		}
@@ -70,28 +72,28 @@ public class DefaultBinderFactory<T> implements BinderFactory<T>, DisposableBean
 		String configurationName;
 		// Fall back to a default if no argument is provided
 		if (StringUtils.isEmpty(name)) {
-			if (binderConfigurations.size() == 0) {
+			if (this.binderConfigurations.size() == 0) {
 				throw new IllegalStateException("A default binder has been requested, but there there is no binder available");
 			}
-			else if (binderConfigurations.size() == 1) {
-				configurationName = binderConfigurations.keySet().iterator().next();
+			else if (this.binderConfigurations.size() == 1) {
+				configurationName = this.binderConfigurations.keySet().iterator().next();
 			}
 			else {
-				if (StringUtils.hasText(defaultBinder)) {
-					configurationName = defaultBinder;
+				if (StringUtils.hasText(this.defaultBinder)) {
+					configurationName = this.defaultBinder;
 				}
 				else {
 					throw new IllegalStateException(
 							"A default binder has been requested, but there is more than one binder available: "
-									+ StringUtils.collectionToCommaDelimitedString(binderConfigurations.keySet()) + ", and"
+									+ StringUtils.collectionToCommaDelimitedString(this.binderConfigurations.keySet()) + ", and"
 									+ " no default binder has been set.");
 				}
 			}
 		} else {
 			configurationName = name;
 		}
-		if (!binderInstanceCache.containsKey(configurationName)) {
-			BinderConfiguration binderConfiguration = binderConfigurations.get(configurationName);
+		if (!this.binderInstanceCache.containsKey(configurationName)) {
+			BinderConfiguration binderConfiguration = this.binderConfigurations.get(configurationName);
 			if (binderConfiguration == null) {
 				throw new IllegalStateException("Unknown binder configuration: " + configurationName);
 			}
@@ -102,7 +104,7 @@ public class DefaultBinderFactory<T> implements BinderFactory<T>, DisposableBean
 				args.add(String.format("--%s=%s",property.getKey(),property.getValue()));
 			}
 			// Initialize the domain with a unique name based on the bootstrapping context setting
-			String defaultDomain = environment != null ? environment.getProperty("spring.jmx.default-domain") : null;
+			String defaultDomain = this.environment != null ? this.environment.getProperty("spring.jmx.default-domain") : null;
 			if (defaultDomain == null) {
 				defaultDomain = "";
 			}
@@ -116,13 +118,18 @@ public class DefaultBinderFactory<T> implements BinderFactory<T>, DisposableBean
 							.sources(binderConfiguration.getBinderType().getConfigurationClasses())
 							.bannerMode(Mode.OFF)
 							.web(false);
+			if (this.environment instanceof ConfigurableEnvironment) {
+				StandardEnvironment environment = new StandardEnvironment();
+				environment.merge((ConfigurableEnvironment) this.environment);
+				springApplicationBuilder.environment(environment);
+			}
 			ConfigurableApplicationContext binderProducingContext =
 					springApplicationBuilder.run(args.toArray(new String[args.size()]));
 			@SuppressWarnings("unchecked")
-			Binder<T> binder = (Binder<T>) binderProducingContext.getBean(Binder.class);
-			binderInstanceCache.put(configurationName, new BinderInstanceHolder<>(binder, binderProducingContext));
+			Binder<T> binder = binderProducingContext.getBean(Binder.class);
+			this.binderInstanceCache.put(configurationName, new BinderInstanceHolder<>(binder, binderProducingContext));
 		}
-		return binderInstanceCache.get(configurationName).getBinderInstance();
+		return this.binderInstanceCache.get(configurationName).getBinderInstance();
 	}
 
 	/**
@@ -142,11 +149,11 @@ public class DefaultBinderFactory<T> implements BinderFactory<T>, DisposableBean
 		}
 
 		public Binder<T> getBinderInstance() {
-			return binderInstance;
+			return this.binderInstance;
 		}
 
 		public ConfigurableApplicationContext getBinderContext() {
-			return binderContext;
+			return this.binderContext;
 		}
 	}
 }

spring-cloud-stream/src/test/java/org/springframework/cloud/stream/binder/BinderFactoryConfigurationTests.java

@@ -33,7 +33,6 @@ import java.net.URL;
 import java.net.URLClassLoader;
 
 import org.junit.Test;
-
 import org.springframework.beans.factory.BeanCreationException;
 import org.springframework.boot.autoconfigure.PropertyPlaceholderAutoConfiguration;
 import org.springframework.boot.builder.SpringApplicationBuilder;
@@ -89,6 +88,17 @@ public class BinderFactoryConfigurationTests {
 		assertThat(defaultBinder, is(binder1));
 	}
 
+	@Test
+	public void loadBinderTypeRegistryWithOneBinderAndSharedEnvironment() throws Exception {
+		ConfigurableApplicationContext context = createBinderTestContext(
+				new String[] {"binder1"}, "binder1.name=foo");
+
+		BinderFactory binderFactory = context.getBean(BinderFactory.class);
+
+		Binder binder1 = binderFactory.getBinder("binder1");
+		assertThat(((StubBinder1)binder1).getName(), is(equalTo("foo")));
+	}
+
 	@Test
 	public void loadBinderTypeRegistryWithTwoBinders() throws Exception {
 

spring-cloud-stream/src/test/java/org/springframework/cloud/stream/binder/stub1/StubBinder1.java

@@ -25,6 +25,16 @@ import org.springframework.cloud.stream.binder.Binder;
  */
 public class StubBinder1 implements Binder {
 
+	private String name;
+
+	public String getName() {
+		return this.name;
+	}
+
+	public void setName(String name) {
+		this.name = name;
+	}
+
 	@Override
 	public void bindConsumer(String name, Object inboundBindTarget, Properties properties) {
 

spring-cloud-stream/src/test/java/org/springframework/cloud/stream/binder/stub1/StubBinder1Configuration.java

@@ -16,6 +16,8 @@
 
 package org.springframework.cloud.stream.binder.stub1;
 
+import org.springframework.boot.context.properties.ConfigurationProperties;
+import org.springframework.boot.context.properties.EnableConfigurationProperties;
 import org.springframework.cloud.stream.binder.Binder;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
@@ -24,9 +26,11 @@ import org.springframework.context.annotation.Configuration;
  * @author Marius Bogoevici
  */
 @Configuration
+@EnableConfigurationProperties
 public class StubBinder1Configuration {
 
 	@Bean
+	@ConfigurationProperties("binder1")
 	public Binder binder() {
 		return new StubBinder1();
 	}