----初始化项目

plugin/trace/pom.xml

@@ -0,0 +1,39 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+  ~ Copyright 1999-2021 Alibaba Group Holding Ltd.
+  ~
+  ~ 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.
+  -->
+
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <parent>
+        <artifactId>nacos-plugin</artifactId>
+        <groupId>com.alibaba.nacos</groupId>
+        <version>${revision}</version>
+    </parent>
+    <modelVersion>4.0.0</modelVersion>
+    
+    <artifactId>nacos-trace-plugin</artifactId>
+    <name>nacos-trace-plugin ${project.version}</name>
+    <url>https://nacos.io</url>
+    <description>Nacos trace plugin pom.xml file</description>
+    <dependencies>
+        <dependency>
+            <groupId>com.alibaba.nacos</groupId>
+            <artifactId>nacos-common</artifactId>
+            <scope>provided</scope>
+        </dependency>
+    </dependencies>
+</project>

plugin/trace/src/main/java/com/alibaba/nacos/plugin/trace/NacosTracePluginManager.java

@@ -0,0 +1,59 @@
+/*
+ * Copyright 1999-2021 Alibaba Group Holding Ltd.
+ *
+ * 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 com.alibaba.nacos.plugin.trace;
+
+import com.alibaba.nacos.common.spi.NacosServiceLoader;
+import com.alibaba.nacos.plugin.trace.spi.NacosTraceSubscriber;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.Collection;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+
+/**
+ * Nacos trace event subscriber manager.
+ *
+ * @author xiweng.yy
+ */
+public class NacosTracePluginManager {
+    
+    private static final Logger LOGGER = LoggerFactory.getLogger(NacosTracePluginManager.class);
+    
+    private static final NacosTracePluginManager INSTANCE = new NacosTracePluginManager();
+    
+    private final Map<String, NacosTraceSubscriber> traceSubscribers;
+    
+    private NacosTracePluginManager() {
+        this.traceSubscribers = new ConcurrentHashMap<>();
+        Collection<NacosTraceSubscriber> plugins = NacosServiceLoader.load(NacosTraceSubscriber.class);
+        for (NacosTraceSubscriber each : plugins) {
+            this.traceSubscribers.put(each.getName(), each);
+            LOGGER.info("[TracePluginManager] Load NacosTraceSubscriber({}) name({}) successfully.", each.getClass(),
+                    each.getName());
+        }
+    }
+    
+    public static NacosTracePluginManager getInstance() {
+        return INSTANCE;
+    }
+    
+    public Collection<NacosTraceSubscriber> getAllTraceSubscribers() {
+        return new HashSet<>(traceSubscribers.values());
+    }
+}

plugin/trace/src/main/java/com/alibaba/nacos/plugin/trace/spi/NacosTraceSubscriber.java

@@ -0,0 +1,60 @@
+/*
+ * Copyright 1999-2021 Alibaba Group Holding Ltd.
+ *
+ * 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 com.alibaba.nacos.plugin.trace.spi;
+
+import com.alibaba.nacos.common.trace.event.TraceEvent;
+
+import java.util.List;
+import java.util.concurrent.Executor;
+
+/**
+ * Nacos trace event subscriber.
+ *
+ * @author xiweng.yy
+ */
+public interface NacosTraceSubscriber {
+    
+    /**
+     * Get the plugin name, if the same name has loaded by nacos, the older one will be replaced by new one.
+     *
+     * @return plugin name
+     */
+    String getName();
+    
+    /**
+     * Event callback.
+     *
+     * @param event {@link TraceEvent}
+     */
+    void onEvent(TraceEvent event);
+    
+    /**
+     * Returns which trace events are this subscriber interested in.
+     *
+     * @return The interested event types.
+     */
+    List<Class<? extends TraceEvent>> subscribeTypes();
+    
+    /**
+     * It is up to the listener to determine whether the callback is asynchronous or synchronous.
+     *
+     * @return {@link Executor}
+     */
+    default Executor executor() {
+        return null;
+    }
+}

plugin/trace/src/test/java/com/alibaba/nacos/plugin/trace/NacosTracePluginManagerTest.java

@@ -0,0 +1,47 @@
+/*
+ * Copyright 1999-2021 Alibaba Group Holding Ltd.
+ *
+ * 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 com.alibaba.nacos.plugin.trace;
+
+import com.alibaba.nacos.plugin.trace.spi.NacosTraceSubscriber;
+import org.junit.Assert;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import static org.junit.Assert.assertFalse;
+
+public class NacosTracePluginManagerTest {
+    
+    @BeforeClass
+    public static void setUp() {
+        NacosTracePluginManager.getInstance();
+    }
+    
+    @Test
+    public void testGetAllTraceSubscribers() {
+        assertFalse(NacosTracePluginManager.getInstance().getAllTraceSubscribers().isEmpty());
+        assertContainsTestPlugin();
+    }
+    
+    private void assertContainsTestPlugin() {
+        for (NacosTraceSubscriber each : NacosTracePluginManager.getInstance().getAllTraceSubscribers()) {
+            if ("trace-plugin-mock".equals(each.getName())) {
+                return;
+            }
+        }
+        Assert.fail("No found plugin named 'trace-plugin-mock'");
+    }
+}

plugin/trace/src/test/java/com/alibaba/nacos/plugin/trace/mock/MockNacosTraceSubscriber.java

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+/*
+ * Copyright 1999-2021 Alibaba Group Holding Ltd.
+ *
+ * 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 com.alibaba.nacos.plugin.trace.mock;
+
+import com.alibaba.nacos.common.trace.event.TraceEvent;
+import com.alibaba.nacos.plugin.trace.spi.NacosTraceSubscriber;
+
+import java.util.List;
+
+public class MockNacosTraceSubscriber implements NacosTraceSubscriber {
+    
+    @Override
+    public String getName() {
+        return "trace-plugin-mock";
+    }
+    
+    @Override
+    public void onEvent(TraceEvent event) {
+    }
+    
+    @Override
+    public List<Class<? extends TraceEvent>> subscribeTypes() {
+        return null;
+    }
+}

plugin/trace/src/test/resources/META-INF/services/com.alibaba.nacos.plugin.trace.spi.NacosTraceSubscriber

@@ -0,0 +1,17 @@
+#
+# Copyright 1999-2021 Alibaba Group Holding Ltd.
+#
+# 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
+#r
+#      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.
+#
+
+com.alibaba.nacos.plugin.trace.mock.MockNacosTraceSubscriber