Watch consul config and refresh when there are changes.

fixes gh-19

spring-cloud-consul-config/pom.xml

@@ -22,6 +22,11 @@
 			<artifactId>spring-boot-starter-web</artifactId>
 			<optional>true</optional>
 		</dependency>
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-actuator</artifactId>
+			<optional>true</optional>
+		</dependency>
 		<dependency>
 			<groupId>org.springframework.retry</groupId>
 			<artifactId>spring-retry</artifactId>

spring-cloud-consul-config/src/main/java/org/springframework/cloud/consul/config/ConfigWatch.java

@@ -0,0 +1,107 @@
+/*
+ * Copyright 2013-2016 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.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.cloud.consul.config;
+
+import java.io.Closeable;
+import java.util.HashMap;
+import java.util.List;
+import java.util.concurrent.atomic.AtomicBoolean;
+import javax.annotation.PostConstruct;
+
+import com.ecwid.consul.v1.ConsulClient;
+import com.ecwid.consul.v1.QueryParams;
+import com.ecwid.consul.v1.Response;
+import com.ecwid.consul.v1.kv.model.GetValue;
+
+import org.springframework.context.ApplicationEventPublisher;
+import org.springframework.context.ApplicationEventPublisherAware;
+import org.springframework.scheduling.annotation.Scheduled;
+
+import lombok.Data;
+import lombok.extern.apachecommons.CommonsLog;
+
+/**
+ * @author Spencer Gibb
+ */
+@CommonsLog
+public class ConfigWatch implements Closeable, ApplicationEventPublisherAware {
+	private final List<String> contexts;
+	private final ConsulClient consul;
+	private AtomicBoolean running = new AtomicBoolean(false);
+	private ApplicationEventPublisher publisher;
+	private HashMap<String, Long> consulIndexes = new HashMap<>();
+
+	public ConfigWatch(List<String> contexts, ConsulClient consul) {
+		this.contexts = contexts;
+		this.consul = consul;
+	}
+
+	@Override
+	public void setApplicationEventPublisher(ApplicationEventPublisher publisher) {
+		this.publisher = publisher;
+	}
+
+	@PostConstruct
+	public void start() {
+		this.running.compareAndSet(false, true);
+	}
+
+	@Scheduled(fixedDelayString = "${spring.cloud.consul.config.watch.delay:10}")
+	public void watchConfigKeyValues() {
+		if (this.running.get()) {
+			for (String context : this.contexts) {
+				if (!context.endsWith("/")) {
+					context = context + "/";
+				}
+
+				try {
+					Long currentIndex = this.consulIndexes.get(context);
+					if (currentIndex == null) {
+						currentIndex = -1L;
+					}
+
+					Response<List<GetValue>> response = this.consul.getKVValues(context, new QueryParams(2, currentIndex));
+
+					Long newIndex = response.getConsulIndex();
+
+					if (newIndex != null && !newIndex.equals(currentIndex)) {
+						// don't publish the same index again, don't publish the first time (-1) so index can be primed
+						if (!this.consulIndexes.containsValue(newIndex) && !currentIndex.equals(-1L)) {
+							this.publisher.publishEvent(new ConsulConfigRefreshEvent(this, new RefreshEventData(context, currentIndex, newIndex)));
+						}
+						this.consulIndexes.put(context, newIndex);
+					}
+
+				} catch (Exception e) {
+					log.error("Error initializing listener for context " + context, e);
+				}
+			}
+		}
+	}
+
+	@Override
+	public void close() {
+		this.running.compareAndSet(true, false);
+	}
+
+	@Data
+	static class RefreshEventData {
+		private final String context;
+		private final Long prevIndex;
+		private final Long newIndex;
+	}
+}

spring-cloud-consul-config/src/main/java/org/springframework/cloud/consul/config/ConsulConfigAutoConfiguration.java

@@ -0,0 +1,51 @@
+/*
+ * Copyright 2013-2016 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.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.cloud.consul.config;
+
+import com.ecwid.consul.v1.ConsulClient;
+
+import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
+import org.springframework.cloud.endpoint.RefreshEndpoint;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+/**
+ * @author Spencer Gibb
+ */
+@Configuration
+public class ConsulConfigAutoConfiguration {
+
+	@Configuration
+	@ConditionalOnClass(RefreshEndpoint.class)
+	protected static class ConsulRefreshConfiguration {
+		@Bean
+		@ConditionalOnBean(RefreshEndpoint.class)
+		public ConsulConfigRefreshListener zookeeperConfigRefreshListener(
+				RefreshEndpoint refreshEndpoint) {
+			return new ConsulConfigRefreshListener(refreshEndpoint);
+		}
+
+		@Bean
+		@ConditionalOnProperty(name = "spring.cloud.consul.config.watch.enabled", matchIfMissing = true)
+		public ConfigWatch configWatch(ConsulPropertySourceLocator locator,
+										   ConsulClient consul) {
+			return new ConfigWatch(locator.getContexts(), consul);
+		}
+	}
+}

spring-cloud-consul-config/src/main/java/org/springframework/cloud/consul/config/ConsulConfigProperties.java

@@ -52,6 +52,16 @@ public class ConsulConfigProperties {
 
 	private String aclToken;
 
+	private Watch watch = new Watch();
+
+	@Data
+	public class Watch {
+		private int waitTime = 2;
+		private boolean enabled = true;
+		private int delay = 10;
+
+	}
+
 	/**
 	 * There are many ways in which we can specify configuration in consul i.e.,
 	 *
@@ -76,7 +86,7 @@ public class ConsulConfigProperties {
 	 *
 	 * @author srikalyan.swayampakula
 	 */
-	public static enum Format {
+	public enum Format {
 		/**
 		 * Indicates that the configuration specified in consul is of type native key values.
 		 */

spring-cloud-consul-config/src/main/java/org/springframework/cloud/consul/config/ConsulConfigRefreshEvent.java

@@ -0,0 +1,45 @@
+/*
+ * Copyright 2013-2016 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.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.cloud.consul.config;
+
+import org.springframework.context.ApplicationEvent;
+
+/**
+ * @author Spencer Gibb
+ */
+public class ConsulConfigRefreshEvent extends ApplicationEvent {
+
+	private Object event;
+
+	/**
+	 * Create a new ApplicationEvent.
+	 *
+	 * @param source the object on which the event initially occurred (never {@code null})
+	 */
+	public ConsulConfigRefreshEvent(Object source, Object event) {
+		super(source);
+		this.event = event;
+	}
+
+	public Object getEvent() {
+		return event;
+	}
+
+	public String getEventDesc() {
+		return event.toString();
+	}
+}

spring-cloud-consul-config/src/main/java/org/springframework/cloud/consul/config/ConsulConfigRefreshListener.java

@@ -0,0 +1,55 @@
+/*
+ * Copyright 2013-2016 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.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.cloud.consul.config;
+
+import java.util.Arrays;
+import java.util.concurrent.atomic.AtomicBoolean;
+
+import org.springframework.boot.context.event.ApplicationReadyEvent;
+import org.springframework.cloud.endpoint.RefreshEndpoint;
+import org.springframework.context.event.EventListener;
+
+import lombok.extern.apachecommons.CommonsLog;
+
+/**
+ * @author Spencer Gibb
+ */
+@CommonsLog
+public class ConsulConfigRefreshListener {
+	private RefreshEndpoint refresh;
+	private AtomicBoolean ready = new AtomicBoolean(false);
+
+	public ConsulConfigRefreshListener(RefreshEndpoint refresh) {
+		this.refresh = refresh;
+	}
+
+	@EventListener
+	public void handle(ApplicationReadyEvent event) {
+		this.ready.compareAndSet(false, true);
+	}
+
+	@EventListener
+	public void handle(ConsulConfigRefreshEvent event) {
+		if (this.ready.get()) { // don't handle events before app is ready
+			log.info("Event received " + event.getEventDesc());
+			if (this.refresh != null) {
+				String[] keys = this.refresh.refresh();
+				log.info("Refresh keys changed: " + Arrays.asList(keys));
+			}
+		}
+	}
+}

spring-cloud-consul-config/src/main/java/org/springframework/cloud/consul/config/ConsulPropertySourceLocator.java

@@ -41,11 +41,17 @@ public class ConsulPropertySourceLocator implements PropertySourceLocator {
 
 	private ConsulConfigProperties properties;
 
+	private List<String> contexts = new ArrayList<>();
+
 	public ConsulPropertySourceLocator(ConsulClient consul, ConsulConfigProperties properties) {
 		this.consul = consul;
 		this.properties = properties;
 	}
 
+	public List<String> getContexts() {
+		return contexts;
+	}
+
 	@Override
 	@Retryable(interceptor = "consulRetryInterceptor")
 	public PropertySource<?> locate(Environment environment) {
@@ -55,21 +61,20 @@ public class ConsulPropertySourceLocator implements PropertySourceLocator {
 			List<String> profiles = Arrays.asList(env.getActiveProfiles());
 
 			String prefix = this.properties.getPrefix();
-			List<String> contexts = new ArrayList<>();
 
 			String defaultContext = prefix + "/" + this.properties.getDefaultContext();
-			contexts.add(defaultContext + "/");
-			addProfiles(contexts, defaultContext, profiles);
+			this.contexts.add(defaultContext + "/");
+			addProfiles(this.contexts, defaultContext, profiles);
 
 			String baseContext = prefix + "/" + appName;
-			contexts.add(baseContext + "/");
-			addProfiles(contexts, baseContext, profiles);
+			this.contexts.add(baseContext + "/");
+			addProfiles(this.contexts, baseContext, profiles);
 
 			CompositePropertySource composite = new CompositePropertySource("consul");
 
-			Collections.reverse(contexts);
+			Collections.reverse(this.contexts);
 
-			for (String propertySourceContext : contexts) {
+			for (String propertySourceContext : this.contexts) {
 				ConsulPropertySource propertySource = create(propertySourceContext);
 				propertySource.init();
 				composite.addPropertySource(propertySource);

spring-cloud-consul-config/src/main/resources/META-INF/spring.factories

@@ -1,3 +1,7 @@
+# Auto Configuration
+org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
+org.springframework.cloud.consul.config.ConsulConfigAutoConfiguration
+
 # Bootstrap Configuration
 org.springframework.cloud.bootstrap.BootstrapConfiguration=\
 org.springframework.cloud.consul.config.ConsulConfigBootstrapConfiguration

spring-cloud-consul-config/src/test/java/org/springframework/cloud/consul/config/ConsulPropertySourceLocatorTests.java

@@ -0,0 +1,129 @@
+/*
+ * Copyright 2013-2016 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.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.cloud.consul.config;
+
+import java.util.UUID;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicInteger;
+
+import com.ecwid.consul.v1.ConsulClient;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
+import org.springframework.boot.builder.SpringApplicationBuilder;
+import org.springframework.cloud.consul.ConsulProperties;
+import org.springframework.cloud.context.scope.refresh.RefreshScope;
+import org.springframework.cloud.endpoint.RefreshEndpoint;
+import org.springframework.context.ConfigurableApplicationContext;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.core.env.ConfigurableEnvironment;
+
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.is;
+import static org.junit.Assert.assertThat;
+
+/**
+ * @author Spencer Gibb
+ */
+public class ConsulPropertySourceLocatorTests {
+	public static final String PREFIX = "_propertySourceLocatorTests_config__";
+	public static final String ROOT = PREFIX + UUID.randomUUID();
+	private ConfigurableApplicationContext context;
+	public static final String KEY = ROOT + "/application/testProp";
+
+	@Configuration
+	@EnableAutoConfiguration
+	static class Config {
+		@Bean
+		public RefreshEndpoint refreshEndpoint(ConfigurableApplicationContext context,
+											   RefreshScope scope) {
+			RefreshEndpoint endpoint = new TestRefreshEndpoint(context, scope);
+			return endpoint;
+		}
+	}
+
+	static class TestRefreshEndpoint extends RefreshEndpoint {
+		private CountDownLatch successLatch = new CountDownLatch(1);
+		private CountDownLatch toManyLatch = new CountDownLatch(1);
+		private AtomicInteger count = new AtomicInteger();
+
+		public TestRefreshEndpoint( ConfigurableApplicationContext context, RefreshScope scope) {
+			super(context, scope);
+		}
+
+		@Override
+		public synchronized String[] refresh() {
+			String[] keys = super.refresh();
+			if (this.count.incrementAndGet() == 1) {
+				this.successLatch.countDown();
+			} else {
+				this.toManyLatch.countDown();
+			}
+			return keys;
+		}
+	}
+
+	private ConfigurableEnvironment environment;
+	private ConsulClient client;
+	private ConsulProperties properties;
+
+	@Before
+	public void setup() {
+		this.properties = new ConsulProperties();
+		this.client = new ConsulClient(properties.getHost(), properties.getPort());
+		this.client.deleteKVValues(PREFIX);
+		this.client.setKVValue(KEY, "testPropVal");
+
+
+		this.context = new SpringApplicationBuilder(Config.class)
+				.web(false)
+				.run("--spring.spring.application.name=testConsulPropertySourceLocator",
+						"--spring.cloud.consul.config.prefix="+ROOT,
+						"spring.cloud.consul.config.watch.delay=1");
+
+		this.client = context.getBean(ConsulClient.class);
+		this.properties = context.getBean(ConsulProperties.class);
+		this.environment = context.getEnvironment();
+	}
+
+	@After
+	public void teardown() {
+		this.client.deleteKVValues(PREFIX);
+	}
+
+	@Test
+	public void propertyLoadedAndUpdated() throws Exception {
+		String testProp = this.environment.getProperty("testProp");
+		assertThat("testProp was wrong", testProp, is(equalTo("testPropVal")));
+
+		this.client.setKVValue(KEY, "testPropValUpdate");
+
+		TestRefreshEndpoint endpoint = this.context.getBean(TestRefreshEndpoint.class);
+		boolean receivedEvent = endpoint.successLatch.await(5, TimeUnit.SECONDS);
+		assertThat("listener didn't receive event", receivedEvent, is(true));
+
+		testProp = this.environment.getProperty("testProp");
+		assertThat("testProp was wrong after update", testProp, is(equalTo("testPropValUpdate")));
+
+		boolean receivedExtraEvent = endpoint.toManyLatch.await(500, TimeUnit.MILLISECONDS);
+		assertThat("refresh called to many times", receivedExtraEvent, is(false));
+	}
+}