Publish spring event named ConfigChangeSpringEvent when the configuration is changed. (#647)

* public config change spring event

* update changelog

* Update ConfigChangeSpringEventTest.java

add license for ConfigChangeSpringEventTest

Co-authored-by: Haotian Zhang <928016560@qq.com>

CHANGELOG.md

@@ -21,3 +21,4 @@
 - [Feature: support read config file from local file system](https://github.com/Tencent/spring-cloud-tencent/pull/640)
 - [fix:optimize expression parser V1.](https://github.com/Tencent/spring-cloud-tencent/pull/642)
 - [Optimize: add transfer metadata unit test.](https://github.com/Tencent/spring-cloud-tencent/pull/646)
+- [feat: publish spring event named ConfigChangeSpringEvent when the configuration is changed](https://github.com/Tencent/spring-cloud-tencent/pull/647)

spring-cloud-starter-tencent-polaris-config/src/main/java/com/tencent/cloud/polaris/config/listener/PolarisConfigChangeEventListener.java

@@ -23,11 +23,14 @@ import java.util.Map;
 import java.util.concurrent.atomic.AtomicBoolean;
 
 import com.google.common.collect.Maps;
+import com.tencent.cloud.polaris.config.spring.event.ConfigChangeSpringEvent;
 import com.tencent.polaris.configuration.api.core.ConfigPropertyChangeInfo;
 
 import org.springframework.boot.context.event.ApplicationStartedEvent;
 import org.springframework.cloud.context.environment.EnvironmentChangeEvent;
 import org.springframework.context.ApplicationEvent;
+import org.springframework.context.ApplicationEventPublisher;
+import org.springframework.context.ApplicationEventPublisherAware;
 import org.springframework.context.ApplicationListener;
 import org.springframework.context.ConfigurableApplicationContext;
 import org.springframework.core.env.ConfigurableEnvironment;
@@ -44,10 +47,12 @@ import static com.tencent.cloud.polaris.config.listener.PolarisConfigListenerCon
  *
  * @author <a href="mailto:iskp.me@gmail.com">Elve.Xu</a> 2022-06-08
  */
-public final class PolarisConfigChangeEventListener implements ApplicationListener<ApplicationEvent> {
+public final class PolarisConfigChangeEventListener implements ApplicationListener<ApplicationEvent>, ApplicationEventPublisherAware {
 
 	private static final AtomicBoolean started = new AtomicBoolean();
 
+	private ApplicationEventPublisher eventPublisher;
+
 	/**
 	 * Handle an application event.
 	 *
@@ -72,6 +77,8 @@ public final class PolarisConfigChangeEventListener implements ApplicationListen
 			ConfigurableEnvironment environment = context.getEnvironment();
 			Map<String, Object> ret = loadEnvironmentProperties(environment);
 			Map<String, ConfigPropertyChangeInfo> changes = merge(ret);
+			ConfigChangeSpringEvent configChangeSpringEvent = new ConfigChangeSpringEvent(Maps.newHashMap(changes));
+			eventPublisher.publishEvent(configChangeSpringEvent);
 			fireConfigChange(changes.keySet(), Maps.newHashMap(changes));
 			changes.clear();
 		}
@@ -106,4 +113,9 @@ public final class PolarisConfigChangeEventListener implements ApplicationListen
 		});
 		return ret;
 	}
+
+	@Override
+	public void setApplicationEventPublisher(ApplicationEventPublisher eventPublisher) {
+		this.eventPublisher = eventPublisher;
+	}
 }

spring-cloud-starter-tencent-polaris-config/src/main/java/com/tencent/cloud/polaris/config/spring/event/ConfigChangeSpringEvent.java

@@ -0,0 +1,70 @@
+/*
+ * Tencent is pleased to support the open source community by making Spring Cloud Tencent available.
+ *
+ * Copyright (C) 2019 THL A29 Limited, a Tencent company. All rights reserved.
+ *
+ * Licensed under the BSD 3-Clause License (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * https://opensource.org/licenses/BSD-3-Clause
+ *
+ * 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 com.tencent.cloud.polaris.config.spring.event;
+
+import java.util.Map;
+import java.util.Set;
+
+import com.tencent.polaris.configuration.api.core.ConfigPropertyChangeInfo;
+
+import org.springframework.context.ApplicationEvent;
+
+/**
+ * A spring change event when config is changed.
+ *
+ * @author Derek Yi 2022-10-16
+ */
+public class ConfigChangeSpringEvent extends ApplicationEvent {
+	/**
+	 * @param source all changed keys map.
+	 */
+	public ConfigChangeSpringEvent(Map<String, ConfigPropertyChangeInfo> source) {
+		super(source);
+	}
+
+	/**
+	 * Get the changed keys.
+	 * @return the list of the keys
+	 */
+	public Set<String> changedKeys() {
+		return changeMap().keySet();
+	}
+
+	/**
+	 * Get a specific change instance for the key specified.
+	 * @param key the changed key
+	 * @return the change instance
+	 */
+	public ConfigPropertyChangeInfo getChange(String key) {
+		return changeMap().get(key);
+	}
+
+	/**
+	 * Check whether the specified key is changed .
+	 * @param key the key
+	 * @return true if the key is changed, false otherwise.
+	 */
+	public boolean isChanged(String key) {
+		return changeMap().containsKey(key);
+	}
+
+	private Map<String, ConfigPropertyChangeInfo> changeMap() {
+		return (Map<String, ConfigPropertyChangeInfo>) getSource();
+	}
+}

spring-cloud-starter-tencent-polaris-config/src/test/java/com/tencent/cloud/polaris/config/spring/event/ConfigChangeSpringEventTest.java

@@ -0,0 +1,80 @@
+/*
+ * Tencent is pleased to support the open source community by making Spring Cloud Tencent available.
+ *
+ * Copyright (C) 2019 THL A29 Limited, a Tencent company. All rights reserved.
+ *
+ * Licensed under the BSD 3-Clause License (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * https://opensource.org/licenses/BSD-3-Clause
+ *
+ * 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 com.tencent.cloud.polaris.config.spring.event;
+
+import java.util.HashMap;
+import java.util.Set;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicInteger;
+
+import com.tencent.polaris.configuration.api.core.ChangeType;
+import com.tencent.polaris.configuration.api.core.ConfigPropertyChangeInfo;
+import org.junit.Assert;
+import org.junit.Test;
+
+import org.springframework.boot.autoconfigure.AutoConfigurations;
+import org.springframework.boot.test.context.runner.ApplicationContextRunner;
+import org.springframework.context.ApplicationListener;
+import org.springframework.context.annotation.Configuration;
+
+
+/**
+ * Test for {@link ConfigChangeSpringEvent}.
+ *
+ * @author derek.yi 2022-10-16
+ */
+public class ConfigChangeSpringEventTest {
+
+	private static CountDownLatch countDownLatch = new CountDownLatch(1);
+
+	private static AtomicInteger receiveEventTimes = new AtomicInteger();
+
+	@Test
+	public void testPublishConfigChangeSpringEvent() {
+		ApplicationContextRunner contextRunner = new ApplicationContextRunner()
+				.withConfiguration(AutoConfigurations.of(ConfigChangeSpringEventListener.class));
+		contextRunner.run(context -> {
+			HashMap<String, ConfigPropertyChangeInfo> changeMap = new HashMap<>();
+			changeMap.put("key", new ConfigPropertyChangeInfo("key", null, "value", ChangeType.ADDED));
+			context.publishEvent(new ConfigChangeSpringEvent(changeMap));
+			countDownLatch.await(5, TimeUnit.SECONDS);
+			Assert.assertEquals(1, receiveEventTimes.get());
+		});
+	}
+
+	@Configuration
+	static class ConfigChangeSpringEventListener implements ApplicationListener<ConfigChangeSpringEvent> {
+
+		@Override
+		public void onApplicationEvent(ConfigChangeSpringEvent event) {
+			Set<String> changedKeys = event.changedKeys();
+			Assert.assertEquals(1, changedKeys.size());
+			Assert.assertTrue(event.isChanged("key"));
+			ConfigPropertyChangeInfo changeInfo = event.getChange("key");
+			Assert.assertNotNull(changeInfo);
+			Assert.assertEquals("key", changeInfo.getPropertyName());
+			Assert.assertEquals("value", changeInfo.getNewValue());
+			Assert.assertEquals(ChangeType.ADDED, changeInfo.getChangeType());
+
+			receiveEventTimes.incrementAndGet();
+			countDownLatch.countDown();
+		}
+	}
+}