Moves ConsulCatalogWatch to TaskScheduler rather than @Scheduled

fixes gh-146

docs/src/main/asciidoc/spring-cloud-consul.adoc

@@ -170,6 +170,17 @@ public String serviceUrl() {
 }
 ----
 
+=== Consul Catalog Watch
+
+The Consul Catalog Watch takes advantage of the ability of consul to https://www.consul.io/docs/agent/watches.html#services[watch services]. The Catalog Watch makes a blocking Consul HTTP API call to determine if any services have changed. If there is new service data a Heartbeat Event is published.
+
+To change the frequency of when the Config Watch is called change `spring.cloud.consul.config.discovery.catalog-services-watch-delay`. The default value is 1000, which is in milliseconds. The delay is the amount of time after the end of the previous invocation and the start of the next.
+
+To disable the Catalog Watch set `spring.cloud.consul.discovery.catalog-services-watch.enabled=false`.
+
+
+The watch uses a Spring `TaskScheduler` to schedule the call to consul. By default it is a `ThreadPoolTaskScheduler` with a `poolSize` of 1. To change the `TaskScheduler`, create a bean of type `TaskScheduler` named with the `ConsulDiscoveryClientConfiguration.CATALOG_WATCH_TASK_SCHEDULER_NAME` constant.
+
 [[spring-cloud-consul-config]]
 == Distributed Configuration with Consul
 

spring-cloud-consul-discovery/src/main/java/org/springframework/cloud/consul/discovery/ConsulCatalogWatch.java

@@ -19,33 +19,51 @@ package org.springframework.cloud.consul.discovery;
 import java.math.BigInteger;
 import java.util.List;
 import java.util.Map;
+import java.util.concurrent.ScheduledFuture;
+import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicReference;
 
-import org.springframework.cloud.client.discovery.event.HeartbeatEvent;
-import org.springframework.context.ApplicationEventPublisher;
-import org.springframework.context.ApplicationEventPublisherAware;
-import org.springframework.scheduling.annotation.Scheduled;
-
 import com.ecwid.consul.v1.ConsulClient;
 import com.ecwid.consul.v1.QueryParams;
 import com.ecwid.consul.v1.Response;
-
+import io.micrometer.core.annotation.Timed;
 import lombok.extern.slf4j.Slf4j;
 
+import org.springframework.cloud.client.discovery.event.HeartbeatEvent;
+import org.springframework.context.ApplicationEventPublisher;
+import org.springframework.context.ApplicationEventPublisherAware;
+import org.springframework.context.SmartLifecycle;
+import org.springframework.scheduling.TaskScheduler;
+import org.springframework.scheduling.concurrent.ThreadPoolTaskScheduler;
+
 /**
  * @author Spencer Gibb
  */
 @Slf4j
-public class ConsulCatalogWatch implements ApplicationEventPublisherAware {
+public class ConsulCatalogWatch implements ApplicationEventPublisherAware, SmartLifecycle {
 
 	private final ConsulDiscoveryProperties properties;
 	private final ConsulClient consul;
+	private final TaskScheduler taskScheduler;
 	private final AtomicReference<BigInteger> catalogServicesIndex = new AtomicReference<>();
+	private final AtomicBoolean running = new AtomicBoolean(false);
 	private ApplicationEventPublisher publisher;
+	private ScheduledFuture<?> watchFuture;
 
 	public ConsulCatalogWatch(ConsulDiscoveryProperties properties, ConsulClient consul) {
+		this(properties, consul, getTaskScheduler());
+    }
+
+	private static ThreadPoolTaskScheduler getTaskScheduler() {
+		ThreadPoolTaskScheduler taskScheduler = new ThreadPoolTaskScheduler();
+		taskScheduler.initialize();
+		return taskScheduler;
+	}
+
+	public ConsulCatalogWatch(ConsulDiscoveryProperties properties, ConsulClient consul, TaskScheduler taskScheduler) {
 		this.properties = properties;
 		this.consul = consul;
+		this.taskScheduler = taskScheduler;
 	}
 
 	@Override
@@ -53,7 +71,43 @@ public class ConsulCatalogWatch implements ApplicationEventPublisherAware {
 		this.publisher = publisher;
 	}
 
-	@Scheduled(fixedDelayString = "${spring.cloud.consul.discovery.catalogServicesWatchDelay:30000}")
+	@Override
+	public boolean isAutoStartup() {
+		return true;
+	}
+
+	@Override
+	public void stop(Runnable callback) {
+		this.stop();
+		callback.run();
+	}
+
+	@Override
+	public void start() {
+		if (this.running.compareAndSet(false, true)) {
+			this.watchFuture = this.taskScheduler.scheduleWithFixedDelay(this::catalogServicesWatch,
+					this.properties.getCatalogServicesWatchDelay());
+		}
+	}
+
+	@Override
+	public void stop() {
+		if (this.running.compareAndSet(true, false) && this.watchFuture != null) {
+			this.watchFuture.cancel(true);
+		}
+	}
+
+	@Override
+	public boolean isRunning() {
+		return false;
+	}
+
+	@Override
+	public int getPhase() {
+		return 0;
+	}
+
+	@Timed(value ="consul.watch-catalog-services")
 	public void catalogServicesWatch() {
 		try {
 			long index = -1;

spring-cloud-consul-discovery/src/main/java/org/springframework/cloud/consul/discovery/ConsulDiscoveryClientConfiguration.java

@@ -16,11 +16,13 @@
 
 package org.springframework.cloud.consul.discovery;
 
+import com.ecwid.consul.v1.ConsulClient;
+
 import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.annotation.Qualifier;
 import org.springframework.boot.autoconfigure.AutoConfigureBefore;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
-import org.springframework.boot.autoconfigure.web.ServerProperties;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
 import org.springframework.cloud.client.CommonsClientAutoConfiguration;
 import org.springframework.cloud.client.discovery.simple.SimpleDiscoveryClientAutoConfiguration;
@@ -28,8 +30,8 @@ import org.springframework.cloud.commons.util.InetUtils;
 import org.springframework.cloud.consul.ConditionalOnConsulEnabled;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
-
-import com.ecwid.consul.v1.ConsulClient;
+import org.springframework.scheduling.TaskScheduler;
+import org.springframework.scheduling.concurrent.ThreadPoolTaskScheduler;
 
 /**
  * @author Spencer Gibb
@@ -42,6 +44,8 @@ import com.ecwid.consul.v1.ConsulClient;
 		CommonsClientAutoConfiguration.class })
 public class ConsulDiscoveryClientConfiguration {
 
+	public static final String CATALOG_WATCH_TASK_SCHEDULER_NAME = "catalogWatchTaskScheduler";
+
 	@Autowired
 	private ConsulClient consulClient;
 
@@ -75,7 +79,14 @@ public class ConsulDiscoveryClientConfiguration {
 	@ConditionalOnMissingBean
 	@ConditionalOnProperty(name = "spring.cloud.consul.discovery.catalog-services-watch.enabled", matchIfMissing = true)
 	public ConsulCatalogWatch consulCatalogWatch(
-			ConsulDiscoveryProperties discoveryProperties) {
-		return new ConsulCatalogWatch(discoveryProperties, consulClient);
+			ConsulDiscoveryProperties discoveryProperties,
+			@Qualifier(CATALOG_WATCH_TASK_SCHEDULER_NAME) TaskScheduler taskScheduler) {
+		return new ConsulCatalogWatch(discoveryProperties, consulClient, taskScheduler);
+	}
+
+	@Bean(name = CATALOG_WATCH_TASK_SCHEDULER_NAME)
+	@ConditionalOnProperty(name = "spring.cloud.consul.discovery.catalog-services-watch.enabled", matchIfMissing = true)
+	public TaskScheduler catalogWatchTaskScheduler() {
+		return new ThreadPoolTaskScheduler();
 	}
 }

spring-cloud-consul-discovery/src/main/java/org/springframework/cloud/consul/discovery/ConsulDiscoveryProperties.java

@@ -91,9 +91,11 @@ public class ConsulDiscoveryProperties {
 	
 	/** Source of how we will determine the address to use */
 	private boolean preferAgentAddress = false;
-	
-	private int catalogServicesWatchDelay = 10;
 
+	/** The delay between calls to watch consul catalog in millis, default is 1000. */
+	private int catalogServicesWatchDelay = 1000;
+
+	/** The number of seconds to block while watching consul catalog, default is 2. */
 	private int catalogServicesWatchTimeout = 2;
 
 	/** Service name */

spring-cloud-consul-discovery/src/test/java/org/springframework/cloud/consul/discovery/configclient/DiscoveryClientConfigServiceAutoConfigurationTests.java

@@ -21,6 +21,7 @@ import java.util.Arrays;
 import org.junit.After;
 import org.junit.Test;
 import org.junit.runner.RunWith;
+
 import org.springframework.boot.autoconfigure.context.PropertyPlaceholderAutoConfiguration;
 import org.springframework.boot.test.util.TestPropertyValues;
 import org.springframework.cloud.client.DefaultServiceInstance;
@@ -40,8 +41,8 @@ import org.springframework.context.annotation.Configuration;
 
 import static org.junit.Assert.assertEquals;
 import static org.mockito.BDDMockito.given;
+import static org.mockito.Mockito.atLeast;
 import static org.mockito.Mockito.mock;
-import static org.mockito.Mockito.times;
 import static org.mockito.Mockito.verify;
 
 /**
@@ -73,7 +74,7 @@ public class DiscoveryClientConfigServiceAutoConfigurationTests {
 						.getBeanNamesForType(ConsulConfigServerAutoConfiguration.class).length);
 		ConsulDiscoveryClient client = this.context.getParent().getBean(
 				ConsulDiscoveryClient.class);
-		verify(client, times(2)).getInstances("configserver");
+		verify(client, atLeast(2)).getInstances("configserver");
 		ConfigClientProperties locator = this.context
 				.getBean(ConfigClientProperties.class);
 		assertEquals("http://foo:7001/", locator.getUri()[0]);