From 15eae700a3437d82131c6db7a7cb6e890f6d65ee Mon Sep 17 00:00:00 2001
From: Artem Bilan <abilan@pivotal.io>
Date: Wed, 15 Aug 2018 16:04:05 -0400
Subject: [PATCH] Move LeaderInitiators to later phase

There is a race condition when Zookeeper `LeaderInitiator` may start
earlier than `CuratorFramework` it depends on.
This is because both of them are configured for the same default `phase` (`0`)

* Make `LeaderInitiator` and `LockRegistryLeaderInitiator` to be started
in the `Integer.MAX_VALUE - 1000` phase by default - as late as possible
* Make `CuratorFrameworkFactoryBean` to start in the `Integer.MIN_VALUE + 1000`
phase - as early as possible
* Alight lifecycle properties from the `LeaderInitiatorFactoryBean` with
defaults in the `LeaderInitiator`
* Simplify a `LeaderListenerParser` to rely on the `LeaderInitiatorFactoryBean`

**Cherry-pick to 5.0.x**
---
 .../leader/LockRegistryLeaderInitiator.java   |  2 +-
 .../config/CuratorFrameworkFactoryBean.java   | 19 ++++++------
 .../config/LeaderInitiatorFactoryBean.java    | 11 +++----
 .../config/xml/LeaderListenerParser.java      | 30 +++++++------------
 .../zookeeper/leader/LeaderInitiator.java     |  4 +--
 5 files changed, 30 insertions(+), 36 deletions(-)

diff --git a/spring-integration-core/src/main/java/org/springframework/integration/support/leader/LockRegistryLeaderInitiator.java b/spring-integration-core/src/main/java/org/springframework/integration/support/leader/LockRegistryLeaderInitiator.java
index 62dfe16d34..f67403959a 100644
--- a/spring-integration-core/src/main/java/org/springframework/integration/support/leader/LockRegistryLeaderInitiator.java
+++ b/spring-integration-core/src/main/java/org/springframework/integration/support/leader/LockRegistryLeaderInitiator.java
@@ -151,7 +151,7 @@ public class LockRegistryLeaderInitiator implements SmartLifecycle, DisposableBe
 	/**
 	 * @see SmartLifecycle which is an extension of org.springframework.context.Phased
 	 */
-	private int phase;
+	private int phase = Integer.MAX_VALUE - 1000;
 
 	/**
 	 * Flag that indicates whether the leadership election for this {@link #candidate} is
diff --git a/spring-integration-zookeeper/src/main/java/org/springframework/integration/zookeeper/config/CuratorFrameworkFactoryBean.java b/spring-integration-zookeeper/src/main/java/org/springframework/integration/zookeeper/config/CuratorFrameworkFactoryBean.java
index 51d5820147..52a62554f6 100644
--- a/spring-integration-zookeeper/src/main/java/org/springframework/integration/zookeeper/config/CuratorFrameworkFactoryBean.java
+++ b/spring-integration-zookeeper/src/main/java/org/springframework/integration/zookeeper/config/CuratorFrameworkFactoryBean.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2015-2016 the original author or authors.
+ * Copyright 2015-2018 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.
@@ -27,10 +27,11 @@ import org.springframework.context.SmartLifecycle;
 import org.springframework.util.Assert;
 
 /**
- * A spring-friendly way to build a {@link CuratorFramework} and implementing {@link SmartLifecycle}.
+ * A Spring-friendly way to build a {@link CuratorFramework} and implementing {@link SmartLifecycle}.
  *
  * @author Gary Russell
  * @author Artem Bilan
+ *
  * @since 4.2
  */
 public class CuratorFrameworkFactoryBean implements FactoryBean<CuratorFramework>, SmartLifecycle {
@@ -42,18 +43,18 @@ public class CuratorFrameworkFactoryBean implements FactoryBean<CuratorFramework
 	/**
 	 * @see SmartLifecycle
 	 */
-	private volatile boolean autoStartup = true;
+	private boolean autoStartup = true;
+
+	/**
+	 * @see SmartLifecycle
+	 */
+	private int phase = Integer.MIN_VALUE + 1000;
 
 	/**
 	 * @see SmartLifecycle
 	 */
 	private volatile boolean running;
 
-	/**
-	 * @see SmartLifecycle
-	 */
-	private volatile int phase;
-
 
 	/**
 	 * Construct an instance using the supplied connection string and using a default
@@ -135,7 +136,7 @@ public class CuratorFrameworkFactoryBean implements FactoryBean<CuratorFramework
 	}
 
 	@Override
-	public CuratorFramework getObject() throws Exception {
+	public CuratorFramework getObject() {
 		return this.client;
 	}
 
diff --git a/spring-integration-zookeeper/src/main/java/org/springframework/integration/zookeeper/config/LeaderInitiatorFactoryBean.java b/spring-integration-zookeeper/src/main/java/org/springframework/integration/zookeeper/config/LeaderInitiatorFactoryBean.java
index ea5b9befa9..658cbed4c0 100644
--- a/spring-integration-zookeeper/src/main/java/org/springframework/integration/zookeeper/config/LeaderInitiatorFactoryBean.java
+++ b/spring-integration-zookeeper/src/main/java/org/springframework/integration/zookeeper/config/LeaderInitiatorFactoryBean.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2015-2016 the original author or authors.
+ * Copyright 2015-2018 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.
@@ -36,6 +36,7 @@ import org.springframework.integration.zookeeper.leader.LeaderInitiator;
  *
  * @author Gary Russell
  * @author Artem Bilan
+ *
  * @since 4.2
  */
 public class LeaderInitiatorFactoryBean
@@ -51,7 +52,7 @@ public class LeaderInitiatorFactoryBean
 
 	private boolean autoStartup = true;
 
-	private int phase;
+	private int phase = Integer.MAX_VALUE - 1000;
 
 	private ApplicationEventPublisher applicationEventPublisher;
 
@@ -136,11 +137,11 @@ public class LeaderInitiatorFactoryBean
 		if (this.leaderInitiator != null) {
 			return this.leaderInitiator.getPhase();
 		}
-		return 0;
+		return this.phase;
 	}
 
 	@Override
-	public void afterPropertiesSet() throws Exception {
+	public void afterPropertiesSet() {
 		if (this.leaderInitiator == null) {
 			this.leaderInitiator = new LeaderInitiator(this.client, this.candidate, this.path);
 			this.leaderInitiator.setPhase(this.phase);
@@ -156,7 +157,7 @@ public class LeaderInitiatorFactoryBean
 	}
 
 	@Override
-	public synchronized LeaderInitiator getObject() throws Exception {
+	public synchronized LeaderInitiator getObject() {
 		return this.leaderInitiator;
 	}
 
diff --git a/spring-integration-zookeeper/src/main/java/org/springframework/integration/zookeeper/config/xml/LeaderListenerParser.java b/spring-integration-zookeeper/src/main/java/org/springframework/integration/zookeeper/config/xml/LeaderListenerParser.java
index 3b8cc7dcac..d6bfed0784 100644
--- a/spring-integration-zookeeper/src/main/java/org/springframework/integration/zookeeper/config/xml/LeaderListenerParser.java
+++ b/spring-integration-zookeeper/src/main/java/org/springframework/integration/zookeeper/config/xml/LeaderListenerParser.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2015-2016 the original author or authors.
+ * Copyright 2015-2018 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.
@@ -16,8 +16,6 @@
 
 package org.springframework.integration.zookeeper.config.xml;
 
-import java.util.UUID;
-
 import org.w3c.dom.Element;
 
 import org.springframework.beans.factory.support.AbstractBeanDefinition;
@@ -25,12 +23,12 @@ import org.springframework.beans.factory.support.BeanDefinitionBuilder;
 import org.springframework.beans.factory.xml.AbstractBeanDefinitionParser;
 import org.springframework.beans.factory.xml.ParserContext;
 import org.springframework.integration.config.xml.IntegrationNamespaceUtils;
-import org.springframework.integration.leader.DefaultCandidate;
-import org.springframework.integration.leader.event.DefaultLeaderEventPublisher;
-import org.springframework.integration.zookeeper.leader.LeaderInitiator;
+import org.springframework.integration.zookeeper.config.LeaderInitiatorFactoryBean;
 
 /**
  * @author Gary Russell
+ * @author Artem Bilan
+ *
  * @since 4.2
  *
  */
@@ -38,20 +36,14 @@ public class LeaderListenerParser extends AbstractBeanDefinitionParser {
 
 	@Override
 	protected AbstractBeanDefinition parseInternal(Element element, ParserContext parserContext) {
-		BeanDefinitionBuilder candidateBuilder = BeanDefinitionBuilder.genericBeanDefinition(DefaultCandidate.class);
-		candidateBuilder.addConstructorArgValue(UUID.randomUUID().toString());
-		candidateBuilder.addConstructorArgValue(element.getAttribute("role"));
+		BeanDefinitionBuilder builder =
+				BeanDefinitionBuilder.genericBeanDefinition(LeaderInitiatorFactoryBean.class)
+						.addPropertyReference("client", element.getAttribute("client"))
+						.addPropertyValue("role", element.getAttribute(IntegrationNamespaceUtils.ROLE))
+						.addPropertyValue("path", element.getAttribute("path"));
 
-		BeanDefinitionBuilder builder = BeanDefinitionBuilder.genericBeanDefinition(LeaderInitiator.class);
-		builder.addConstructorArgReference(element.getAttribute("client"));
-		builder.addConstructorArgValue(candidateBuilder.getBeanDefinition());
-		builder.addConstructorArgValue(element.getAttribute("path"));
-		IntegrationNamespaceUtils.setValueIfAttributeDefined(builder, element, "auto-startup");
-		IntegrationNamespaceUtils.setValueIfAttributeDefined(builder, element, "phase");
-
-		BeanDefinitionBuilder publisherBuilder = BeanDefinitionBuilder
-				.genericBeanDefinition(DefaultLeaderEventPublisher.class);
-		builder.addPropertyValue("leaderEventPublisher", publisherBuilder.getBeanDefinition());
+		IntegrationNamespaceUtils.setValueIfAttributeDefined(builder, element, IntegrationNamespaceUtils.AUTO_STARTUP);
+		IntegrationNamespaceUtils.setValueIfAttributeDefined(builder, element, IntegrationNamespaceUtils.PHASE);
 
 		return builder.getBeanDefinition();
 	}
diff --git a/spring-integration-zookeeper/src/main/java/org/springframework/integration/zookeeper/leader/LeaderInitiator.java b/spring-integration-zookeeper/src/main/java/org/springframework/integration/zookeeper/leader/LeaderInitiator.java
index 514930f90b..2143b47bab 100644
--- a/spring-integration-zookeeper/src/main/java/org/springframework/integration/zookeeper/leader/LeaderInitiator.java
+++ b/spring-integration-zookeeper/src/main/java/org/springframework/integration/zookeeper/leader/LeaderInitiator.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2014-2017 the original author or authors.
+ * Copyright 2014-2018 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.
@@ -88,7 +88,7 @@ public class LeaderInitiator implements SmartLifecycle {
 	/**
 	 * @see SmartLifecycle which is an extension of org.springframework.context.Phased
 	 */
-	private volatile int phase;
+	private volatile int phase = Integer.MAX_VALUE - 1000;
 
 	/**
 	 * Flag that indicates whether the leadership election for