Make ContextIdApplicationContextInitializer produce unique IDs

Closes gh-11023

spring-boot-project/spring-boot-docs/src/main/asciidoc/appendix-application-properties.adoc

@@ -47,7 +47,6 @@ content into your application. Rather, pick only the properties that you need.
 	spring.aop.proxy-target-class=true # Whether subclass-based (CGLIB) proxies are to be created (true), as opposed to standard Java interface-based proxies (false).
 
 	# IDENTITY ({sc-spring-boot}/context/ContextIdApplicationContextInitializer.{sc-ext}[ContextIdApplicationContextInitializer])
-	spring.application.index= # Application index.
 	spring.application.name= # Application name.
 
 	# ADMIN ({sc-spring-boot-autoconfigure}/admin/SpringApplicationAdminJmxAutoConfiguration.{sc-ext}[SpringApplicationAdminJmxAutoConfiguration])

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/context/ContextIdApplicationContextInitializer.java

 /*
- * Copyright 2012-2017 the original author or authors.
+ * Copyright 2012-2018 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 +16,8 @@
 
 package org.springframework.boot.context;
 
+import java.util.concurrent.atomic.AtomicLong;
+
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.ApplicationContextInitializer;
 import org.springframework.context.ConfigurableApplicationContext;
@@ -24,73 +26,19 @@ import org.springframework.core.env.ConfigurableEnvironment;
 import org.springframework.util.StringUtils;
 
 /**
- * {@link ApplicationContextInitializer} that set the Spring
- * {@link ApplicationContext#getId() ApplicationContext ID}. The following environment
- * properties will be consulted to create the ID:
- * <ul>
- * <li>spring.application.name</li>
- * <li>vcap.application.name</li>
- * <li>spring.config.name</li>
- * </ul>
- * If no property is set the ID 'application' will be used.
- *
- * <p>
- * In addition the following environment properties will be consulted to append a relevant
- * port or index:
- *
- * <ul>
- * <li>spring.application.index</li>
- * <li>vcap.application.instance_index</li>
- * <li>PORT</li>
- * </ul>
+ * {@link ApplicationContextInitializer} that sets the Spring
+ * {@link ApplicationContext#getId() ApplicationContext ID}. The
+ * {@code spring.application.name} property is used to create the ID. If the property is
+ * not set {@code application} is used.
  *
  * @author Dave Syer
+ * @author Andy Wilkinson
  */
 public class ContextIdApplicationContextInitializer implements
 		ApplicationContextInitializer<ConfigurableApplicationContext>, Ordered {
 
-	/**
-	 * Placeholder pattern to resolve for application name. The following order is used to
-	 * find the name:
-	 * <ul>
-	 * <li>{@code spring.application.name}</li>
-	 * <li>{@code vcap.application.name}</li>
-	 * <li>{@code spring.config.name}</li>
-	 * </ul>
-	 * This order allows the user defined name to take precedence over the platform
-	 * defined name. If no property is defined {@code 'application'} will be used.
-	 */
-	private static final String NAME_PATTERN = "${spring.application.name:${vcap.application.name:${spring.config.name:application}}}";
-
-	/**
-	 * Placeholder pattern to resolve for application index. The following order is used
-	 * to find the name:
-	 * <ul>
-	 * <li>{@code vcap.application.instance_index}</li>
-	 * <li>{@code spring.application.index}</li>
-	 * <li>{@code server.port}</li>
-	 * <li>{@code PORT}</li>
-	 * </ul>
-	 * This order favors a platform defined index over any user defined value.
-	 */
-	private static final String INDEX_PATTERN = "${vcap.application.instance_index:${spring.application.index:${server.port:${PORT:null}}}}";
-
-	private final String name;
-
 	private int order = Ordered.LOWEST_PRECEDENCE - 10;
 
-	public ContextIdApplicationContextInitializer() {
-		this(NAME_PATTERN);
-	}
-
-	/**
-	 * Create a new {@link ContextIdApplicationContextInitializer} instance.
-	 * @param name the name of the application (can include placeholders)
-	 */
-	public ContextIdApplicationContextInitializer(String name) {
-		this.name = name;
-	}
-
 	public void setOrder(int order) {
 		this.order = order;
 	}
@@ -102,21 +50,46 @@ public class ContextIdApplicationContextInitializer implements
 
 	@Override
 	public void initialize(ConfigurableApplicationContext applicationContext) {
-		applicationContext.setId(getApplicationId(applicationContext.getEnvironment()));
+		ContextId contextId = getContextId(applicationContext);
+		applicationContext.setId(contextId.getId());
+		applicationContext.getBeanFactory().registerSingleton(ContextId.class.getName(),
+				contextId);
+	}
+
+	private ContextId getContextId(ConfigurableApplicationContext applicationContext) {
+		ApplicationContext parent = applicationContext.getParent();
+		if (parent != null && parent.containsBean(ContextId.class.getName())) {
+			return parent.getBean(ContextId.class).createChildId();
+		}
+		return new ContextId(getApplicationId(applicationContext.getEnvironment()));
 	}
 
 	private String getApplicationId(ConfigurableEnvironment environment) {
-		String name = environment.resolvePlaceholders(this.name);
-		String index = environment.resolvePlaceholders(INDEX_PATTERN);
-		String profiles = StringUtils
-				.arrayToCommaDelimitedString(environment.getActiveProfiles());
-		if (StringUtils.hasText(profiles)) {
-			name = name + ":" + profiles;
+		String name = environment.getProperty("spring.application.name");
+		return StringUtils.hasText(name) ? name : "application";
+	}
+
+	/**
+	 * The ID of a context.
+	 */
+	class ContextId {
+
+		private final AtomicLong children = new AtomicLong(0);
+
+		private final String id;
+
+		ContextId(String id) {
+			this.id = id;
 		}
-		if (!"null".equals(index)) {
-			name = name + ":" + index;
+
+		ContextId createChildId() {
+			return new ContextId(this.id + "-" + this.children.incrementAndGet());
 		}
-		return name;
+
+		String getId() {
+			return this.id;
+		}
+
 	}
 
 }

spring-boot-project/spring-boot/src/main/resources/META-INF/additional-spring-configuration-metadata.json

@@ -143,12 +143,6 @@
       "sourceType": "org.springframework.boot.context.ContextIdApplicationContextInitializer",
       "description": "Application name."
     },
-    {
-      "name": "spring.application.index",
-      "type": "java.lang.Integer",
-      "sourceType": "org.springframework.boot.context.ContextIdApplicationContextInitializer",
-      "description": "Application index."
-    },
     {
       "name": "spring.beaninfo.ignore",
       "type": "java.lang.Boolean",

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/context/ContextIdApplicationContextInitializerTests.java

 /*
- * Copyright 2012-2017 the original author or authors.
+ * Copyright 2012-2018 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 +16,11 @@
 
 package org.springframework.boot.context;
 
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+import org.junit.After;
 import org.junit.Test;
 
 import org.springframework.context.ConfigurableApplicationContext;
@@ -33,50 +38,67 @@ public class ContextIdApplicationContextInitializerTests {
 
 	private final ContextIdApplicationContextInitializer initializer = new ContextIdApplicationContextInitializer();
 
+	private List<ConfigurableApplicationContext> contexts = new ArrayList<>();
+
+	@After
+	public void closeContexts() {
+		Collections.reverse(this.contexts);
+		this.contexts.forEach(ConfigurableApplicationContext::close);
+	}
+
 	@Test
-	public void testDefaults() {
-		ConfigurableApplicationContext context = new AnnotationConfigApplicationContext();
-		this.initializer.initialize(context);
+	public void singleContextWithDefaultName() {
+		ConfigurableApplicationContext context = createContext(null);
 		assertThat(context.getId()).isEqualTo("application");
 	}
 
 	@Test
-	public void testNameAndPort() {
-		ConfigurableApplicationContext context = new AnnotationConfigApplicationContext();
-		TestPropertySourceUtils.addInlinedPropertiesToEnvironment(context,
-				"spring.application.name=foo", "PORT=8080");
-		this.initializer.initialize(context);
-		assertThat(context.getId()).isEqualTo("foo:8080");
+	public void singleContextWithCustomName() {
+		ConfigurableApplicationContext context = createContext(null,
+				"spring.application.name=test");
+		assertThat(context.getId()).isEqualTo("test");
 	}
 
 	@Test
-	public void testNameAndProfiles() {
-		ConfigurableApplicationContext context = new AnnotationConfigApplicationContext();
-		TestPropertySourceUtils.addInlinedPropertiesToEnvironment(context,
-				"spring.application.name=foo", "spring.profiles.active=spam,bar",
-				"spring.application.index=12");
-		this.initializer.initialize(context);
-		assertThat(context.getId()).isEqualTo("foo:spam,bar:12");
+	public void linearHierarchy() {
+		ConfigurableApplicationContext grandparent = createContext(null);
+		ConfigurableApplicationContext parent = createContext(grandparent);
+		ConfigurableApplicationContext child = createContext(parent);
+		assertThat(child.getId()).isEqualTo("application-1-1");
 	}
 
 	@Test
-	public void testCloudFoundry() {
-		ConfigurableApplicationContext context = new AnnotationConfigApplicationContext();
-		TestPropertySourceUtils.addInlinedPropertiesToEnvironment(context,
-				"spring.config.name=foo", "PORT=8080", "vcap.application.name=bar",
-				"vcap.application.instance_index=2");
-		this.initializer.initialize(context);
-		assertThat(context.getId()).isEqualTo("bar:2");
+	public void complexHierarchy() {
+		ConfigurableApplicationContext grandparent = createContext(null);
+		ConfigurableApplicationContext parent1 = createContext(grandparent);
+		ConfigurableApplicationContext parent2 = createContext(grandparent);
+		ConfigurableApplicationContext child1_1 = createContext(parent1);
+		assertThat(child1_1.getId()).isEqualTo("application-1-1");
+		ConfigurableApplicationContext child1_2 = createContext(parent1);
+		assertThat(child1_2.getId()).isEqualTo("application-1-2");
+		ConfigurableApplicationContext child2_1 = createContext(parent2);
+		assertThat(child2_1.getId()).isEqualTo("application-2-1");
 	}
 
 	@Test
-	public void testExplicitNameIsChosenInFavorOfCloudFoundry() {
+	public void contextWithParentWithNoContextIdFallsBackToDefaultId() {
+		ConfigurableApplicationContext parent = new AnnotationConfigApplicationContext();
+		this.contexts.add(parent);
+		parent.refresh();
+		assertThat(createContext(parent).getId()).isEqualTo("application");
+	}
+
+	private ConfigurableApplicationContext createContext(
+			ConfigurableApplicationContext parent, String... properties) {
 		ConfigurableApplicationContext context = new AnnotationConfigApplicationContext();
-		TestPropertySourceUtils.addInlinedPropertiesToEnvironment(context,
-				"spring.application.name=spam", "spring.config.name=foo", "PORT=8080",
-				"vcap.application.name=bar", "vcap.application.instance_index=2");
+		TestPropertySourceUtils.addInlinedPropertiesToEnvironment(context, properties);
+		if (parent != null) {
+			context.setParent(parent);
+		}
 		this.initializer.initialize(context);
-		assertThat(context.getId()).isEqualTo("spam:2");
+		context.refresh();
+		this.contexts.add(context);
+		return context;
 	}
 
 }