INT-4489: MessageHistory: Allow runtime beans

JIRA: https://jira.spring.io/browse/INT-4489

Make `MessageHistoryConfigurer` as a `BeanPostProcessor` and apply
tracking logic to processed beans if it is already started.

**Cherry-pick to 5.0.x**

spring-integration-core/src/main/java/org/springframework/integration/history/MessageHistoryConfigurer.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2018 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.
@@ -18,8 +18,8 @@ package org.springframework.integration.history;
 
 import java.util.Arrays;
 import java.util.Collection;
-import java.util.HashSet;
 import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
@@ -29,6 +29,7 @@ import org.springframework.beans.factory.BeanFactory;
 import org.springframework.beans.factory.BeanFactoryAware;
 import org.springframework.beans.factory.BeanFactoryUtils;
 import org.springframework.beans.factory.ListableBeanFactory;
+import org.springframework.beans.factory.config.BeanPostProcessor;
 import org.springframework.beans.factory.support.BeanDefinitionValidationException;
 import org.springframework.context.SmartLifecycle;
 import org.springframework.integration.support.management.IntegrationManagedResource;
@@ -49,26 +50,24 @@ import org.springframework.util.StringUtils;
  */
 @ManagedResource
 @IntegrationManagedResource
-public class MessageHistoryConfigurer implements SmartLifecycle, BeanFactoryAware {
+public class MessageHistoryConfigurer implements SmartLifecycle, BeanFactoryAware, BeanPostProcessor {
 
 	private final Log logger = LogFactory.getLog(this.getClass());
 
-	private volatile String[] componentNamePatterns = new String[] { "*" };
+	private final Set<TrackableComponent> currentlyTrackedComponents = ConcurrentHashMap.newKeySet();
 
-	private volatile boolean componentNamePatternsExplicitlySet;
+	private String[] componentNamePatterns = new String[] { "*" };
 
-	private final Set<String> currentlyTrackedComponentNames = new HashSet<String>();
+	private boolean componentNamePatternsExplicitlySet;
 
-	private volatile BeanFactory beanFactory;
+	private ListableBeanFactory beanFactory;
+
+	private boolean autoStartup = true;
+
+	private int phase = Integer.MIN_VALUE;
 
 	private volatile boolean running;
 
-	private volatile boolean autoStartup = true;
-
-	private final int phase = Integer.MIN_VALUE;
-
-	private final Object lifecycleMonitor = new Object();
-
 
 	/**
 	 * The patterns for which components will be tracked; default '*' (all trackable
@@ -84,10 +83,10 @@ public class MessageHistoryConfigurer implements SmartLifecycle, BeanFactoryAwar
 		}
 		Arrays.sort(trimmedAndSortedComponentNamePatterns);
 		Assert.isTrue(!this.componentNamePatternsExplicitlySet
-				|| Arrays.equals(this.componentNamePatterns, trimmedAndSortedComponentNamePatterns),
-					"When more than one message history definition " +
-					"(@EnableMessageHistory or <message-history>)" +
-					" is found in the context, they all must have the same 'componentNamePatterns'");
+						|| Arrays.equals(this.componentNamePatterns, trimmedAndSortedComponentNamePatterns),
+				"When more than one message history definition " +
+						"(@EnableMessageHistory or <message-history>)" +
+						" is found in the context, they all must have the same 'componentNamePatterns'");
 		this.componentNamePatterns = trimmedAndSortedComponentNamePatterns;
 		this.componentNamePatternsExplicitlySet = true;
 	}
@@ -136,13 +135,30 @@ public class MessageHistoryConfigurer implements SmartLifecycle, BeanFactoryAwar
 
 	@Override
 	public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
-		this.beanFactory = beanFactory;
+		Assert.isInstanceOf(ListableBeanFactory.class, beanFactory,
+				"The provided 'beanFactory' must be of 'ListableBeanFactory' type.");
+		this.beanFactory = (ListableBeanFactory) beanFactory;
 	}
 
-	private static Collection<TrackableComponent> getTrackableComponents(ListableBeanFactory beanFactory) {
-		return BeanFactoryUtils.beansOfTypeIncludingAncestors(beanFactory, TrackableComponent.class).values();
+	@Override
+	public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
+		if (bean instanceof TrackableComponent && this.running) {
+			trackComponentIfAny((TrackableComponent) bean);
+		}
+		return bean;
 	}
 
+	private void trackComponentIfAny(TrackableComponent component) {
+		String componentName = component.getComponentName();
+		boolean shouldTrack = PatternMatchUtils.simpleMatch(this.componentNamePatterns, componentName);
+		component.setShouldTrack(shouldTrack);
+		if (shouldTrack) {
+			this.currentlyTrackedComponents.add(component);
+			if (this.logger.isInfoEnabled()) {
+				this.logger.info("Enabling MessageHistory tracking for component '" + componentName + "'");
+			}
+		}
+	}
 
 	/*
 	 * SmartLifecycle implementation
@@ -153,11 +169,19 @@ public class MessageHistoryConfigurer implements SmartLifecycle, BeanFactoryAwar
 		return this.running;
 	}
 
+	public void setAutoStartup(boolean autoStartup) {
+		this.autoStartup = autoStartup;
+	}
+
 	@Override
 	public boolean isAutoStartup() {
 		return this.autoStartup;
 	}
 
+	public void setPhase(int phase) {
+		this.phase = phase;
+	}
+
 	@Override
 	public int getPhase() {
 		return this.phase;
@@ -166,20 +190,12 @@ public class MessageHistoryConfigurer implements SmartLifecycle, BeanFactoryAwar
 	@ManagedOperation
 	@Override
 	public void start() {
-		synchronized (this.lifecycleMonitor) {
-			if (!this.running && this.beanFactory instanceof ListableBeanFactory) {
-				for (TrackableComponent component : getTrackableComponents((ListableBeanFactory) this.beanFactory)) {
-					String componentName = component.getComponentName();
-					boolean shouldTrack = PatternMatchUtils.simpleMatch(this.componentNamePatterns, componentName);
-					component.setShouldTrack(shouldTrack);
-					if (shouldTrack) {
-						this.currentlyTrackedComponentNames.add(componentName);
-						if (this.logger.isInfoEnabled()) {
-							this.logger.info("Enabling MessageHistory tracking for component '" + componentName + "'");
-						}
-					}
+		synchronized (this.currentlyTrackedComponents) {
+			if (!this.running) {
+				for (TrackableComponent component : getTrackableComponents(this.beanFactory)) {
+					trackComponentIfAny(component);
+					this.running = true;
 				}
-				this.running = true;
 			}
 		}
 	}
@@ -187,20 +203,19 @@ public class MessageHistoryConfigurer implements SmartLifecycle, BeanFactoryAwar
 	@ManagedOperation
 	@Override
 	public void stop() {
-		synchronized (this.lifecycleMonitor) {
-			if (this.running && this.beanFactory instanceof ListableBeanFactory) {
-				for (TrackableComponent component : getTrackableComponents((ListableBeanFactory) this.beanFactory)) {
-					String componentName = component.getComponentName();
-					if (this.currentlyTrackedComponentNames.contains(componentName)) {
-						component.setShouldTrack(false);
-						if (this.logger.isInfoEnabled()) {
-							this.logger.info("Disabling MessageHistory tracking for component '" + componentName + "'");
-						}
+		synchronized (this.currentlyTrackedComponents) {
+			if (this.running) {
+				this.currentlyTrackedComponents.forEach(component -> {
+					component.setShouldTrack(false);
+					if (this.logger.isInfoEnabled()) {
+						this.logger.info("Disabling MessageHistory tracking for component '"
+								+ component.getComponentName() + "'");
 					}
-				}
-				this.currentlyTrackedComponentNames.clear();
-				this.running = false;
+				});
+
+				this.currentlyTrackedComponents.clear();
 				this.componentNamePatternsExplicitlySet = false; // allow pattern changes
+				this.running = false;
 			}
 		}
 	}
@@ -211,4 +226,8 @@ public class MessageHistoryConfigurer implements SmartLifecycle, BeanFactoryAwar
 		callback.run();
 	}
 
+	private static Collection<TrackableComponent> getTrackableComponents(ListableBeanFactory beanFactory) {
+		return BeanFactoryUtils.beansOfTypeIncludingAncestors(beanFactory, TrackableComponent.class).values();
+	}
+
 }

spring-integration-core/src/test/java/org/springframework/integration/dsl/manualflow/ManualFlowTests.java

@@ -41,6 +41,7 @@ import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicReference;
 import java.util.function.Supplier;
 
+import org.hamcrest.Matchers;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 
@@ -58,6 +59,7 @@ import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.Scope;
 import org.springframework.integration.channel.QueueChannel;
 import org.springframework.integration.config.EnableIntegration;
+import org.springframework.integration.config.EnableMessageHistory;
 import org.springframework.integration.core.MessageProducer;
 import org.springframework.integration.core.MessagingTemplate;
 import org.springframework.integration.dsl.IntegrationFlow;
@@ -71,6 +73,7 @@ import org.springframework.integration.dsl.context.IntegrationFlowContext;
 import org.springframework.integration.dsl.context.IntegrationFlowContext.IntegrationFlowRegistration;
 import org.springframework.integration.endpoint.MessageProducerSupport;
 import org.springframework.integration.handler.AbstractReplyProducingMessageHandler;
+import org.springframework.integration.history.MessageHistory;
 import org.springframework.integration.support.SmartLifecycleRoleController;
 import org.springframework.integration.transformer.MessageTransformingHandler;
 import org.springframework.messaging.Message;
@@ -254,6 +257,12 @@ public class ManualFlowTests {
 		assertNotNull(receive);
 		assertEquals("test", receive.getPayload());
 
+		MessageHistory messageHistory = MessageHistory.read(receive);
+		assertNotNull(messageHistory);
+		String messageHistoryString = messageHistory.toString();
+		assertThat(messageHistoryString, Matchers.containsString("dynamicFlow.input"));
+		assertThat(messageHistoryString, Matchers.containsString("dynamicFlow.subFlow#0.channel#1"));
+
 		this.integrationFlowContext.remove("dynamicFlow");
 	}
 
@@ -475,6 +484,7 @@ public class ManualFlowTests {
 
 	@Configuration
 	@EnableIntegration
+	@EnableMessageHistory
 	public static class RootConfiguration {
 
 		@Bean

src/reference/asciidoc/message-history.adoc

@@ -73,8 +73,7 @@ This feature might be useful to temporarily turn on history to analyze a system.
 The MBean's object name is `"<domain>:name=messageHistoryConfigurer,type=MessageHistoryConfigurer"`.
 
 IMPORTANT: If multiple beans (declared by `@EnableMessageHistory` and/or `<message-history/>`) they all must have identical component name patterns (when trimmed and sorted).
-*Do not use a generic
-	`<bean/>` definition for the `MessageHistoryConfigurer`*.
+*Do not use a generic `<bean/>` definition for the `MessageHistoryConfigurer`*.
 
 NOTE: Remember that by definition the Message History header is immutable (you can't re-write history, although some try).
 Therefore, when writing Message History values, the components are either creating brand new Messages (when the component is an origin), or they are copying the history from a request Message, modifying it and setting the new list on a reply Message.