Add SLF4J extension

sentinel-extension/pom.xml

@@ -22,6 +22,7 @@
         <module>sentinel-datasource-spring-cloud-config</module>
         <module>sentinel-datasource-consul</module>
         <module>sentinel-datasource-etcd</module>
+        <module>sentinel-logging-extension-slf4j</module>
     </modules>
 
 </project>

sentinel-extension/sentinel-logging-extension-slf4j/README.md

@@ -0,0 +1,49 @@
+# Sentinel Logging Extension SLF4J
+
+To use Sentinel Logging Extension SLF4J with Log4j2, you should add the following dependency firstly:
+
+```xml
+<dependency>
+    <groupId>com.alibaba.csp</groupId>
+    <artifactId>sentinel-logging-extension-slf4j</artifactId>
+    <version>x.y.z</version>
+</dependency>
+<dependency>
+    <groupId>org.slf4j</groupId>
+    <artifactId>slf4j-api</artifactId>
+    <version>${slf4j.version}</version>
+</dependency>
+```
+If you want to use Slf4j with Log4j2, you can add dependencies of Log4j2 and the binding about Log4j2 and SLF4J.
+Then you should provide logging configuration as specification of the logging framework. 
+And you can add Sentinel's Loggers that it name is `sentinelRecordLogger` or `sentinelCommandCenterLogger` for your needs. For example: 
+
+```xml
+<?xml version="1.0" encoding="UTF-8" ?>
+<Configuration>
+    <Appenders>
+        <Console name="Console" target="SYSTEM_OUT">
+            <PatternLayout pattern="%-5level %logger - %msg%n"/>
+        </Console>
+        <File name="FILE" fileName="sentinel-record.log" append="false">
+            <PatternLayout pattern="%-5level %logger - %msg%n"/>
+        </File>
+        <File name="FILE2" fileName="sentinel-command-center.log" append="false">
+            <PatternLayout pattern="%-5level %logger - %msg%n"/>
+        </File>
+    </Appenders>
+    <Loggers>
+        <Root level="info"/>
+        <logger name="sentinelRecordLogger" level="trace">
+            <appender-ref ref="Console" />
+            <appender-ref ref="FILE" />
+        </logger>
+        <logger name="sentinelCommandCenterLogger" level="trace">
+            <appender-ref ref="Console" />
+            <appender-ref ref="FILE2" />
+        </logger>
+    </Loggers>
+</Configuration>
+```
+
+

sentinel-extension/sentinel-logging-extension-slf4j/pom.xml

@@ -0,0 +1,60 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<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>sentinel-parent</artifactId>
+        <groupId>com.alibaba.csp</groupId>
+        <version>1.7.2-SNAPSHOT</version>
+    </parent>
+    <modelVersion>4.0.0</modelVersion>
+
+    <artifactId>sentinel-logging-extension-slf4j</artifactId>
+    <packaging>jar</packaging>
+
+    <properties>
+        <java.source.version>1.7</java.source.version>
+        <java.target.version>1.7</java.target.version>
+        <slf4j.version>1.7.25</slf4j.version>
+        <log4j2.version>2.12.1</log4j2.version>
+    </properties>
+
+    <dependencies>
+        <dependency>
+            <groupId>com.alibaba.csp</groupId>
+            <artifactId>sentinel-transport-common</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.slf4j</groupId>
+            <artifactId>slf4j-api</artifactId>
+            <version>${slf4j.version}</version>
+            <scope>provided</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.logging.log4j</groupId>
+            <artifactId>log4j-core</artifactId>
+            <version>${log4j2.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.logging.log4j</groupId>
+            <artifactId>log4j-slf4j-impl</artifactId>
+            <version>${log4j2.version}</version>
+            <scope>test</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <scope>test</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>com.github.stefanbirkner</groupId>
+            <artifactId>system-rules</artifactId>
+            <version>1.16.1</version>
+            <scope>test</scope>
+        </dependency>
+
+    </dependencies>
+</project>

sentinel-extension/sentinel-logging-extension-slf4j/src/main/java/com/alibaba/csp/sentinel/logging/slf4j/CommandCenterLogLogger.java

@@ -0,0 +1,81 @@
+/*
+ * Copyright 1999-2018 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.csp.sentinel.logging.slf4j;
+
+import com.alibaba.csp.sentinel.log.LogTarget;
+import com.alibaba.csp.sentinel.log.Logger;
+import com.alibaba.csp.sentinel.transport.log.CommandCenterLog;
+import org.slf4j.LoggerFactory;
+
+/**
+ * @author wavesZh
+ */
+@LogTarget(CommandCenterLog.LOGGER_NAME)
+public class CommandCenterLogLogger implements Logger {
+
+    private final org.slf4j.Logger logger = LoggerFactory.getLogger(CommandCenterLog.LOGGER_NAME);
+
+    @Override
+    public void info(String format, Object... arguments) {
+        logger.info(format, arguments);
+    }
+
+    @Override
+    public void info(String msg, Throwable e) {
+        logger.info(msg, e);
+    }
+
+    @Override
+    public void warn(String format, Object... arguments) {
+        logger.warn(format, arguments);
+    }
+
+    @Override
+    public void warn(String msg, Throwable e) {
+        logger.warn(msg, e);
+    }
+
+    @Override
+    public void trace(String format, Object... arguments) {
+        logger.trace(format, arguments);
+    }
+
+    @Override
+    public void trace(String msg, Throwable e) {
+        logger.trace(msg, e);
+    }
+
+    @Override
+    public void debug(String format, Object... arguments) {
+        logger.debug(format, arguments);
+    }
+
+    @Override
+    public void debug(String msg, Throwable e) {
+        logger.debug(msg, e);
+    }
+
+    @Override
+    public void error(String format, Object... arguments) {
+        logger.error(format, arguments);
+    }
+
+    @Override
+    public void error(String msg, Throwable e) {
+        logger.error(msg, e);
+    }
+
+}

sentinel-extension/sentinel-logging-extension-slf4j/src/main/java/com/alibaba/csp/sentinel/logging/slf4j/RecordLogLogger.java

@@ -0,0 +1,81 @@
+/*
+ * Copyright 1999-2018 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.csp.sentinel.logging.slf4j;
+
+import com.alibaba.csp.sentinel.log.LogTarget;
+import com.alibaba.csp.sentinel.log.Logger;
+import com.alibaba.csp.sentinel.log.RecordLog;
+import org.slf4j.LoggerFactory;
+
+/**
+ * @author wavesZh
+ */
+@LogTarget(RecordLog.LOGGER_NAME)
+public class RecordLogLogger implements Logger {
+
+    private final org.slf4j.Logger logger = LoggerFactory.getLogger(RecordLog.LOGGER_NAME);
+
+    @Override
+    public void info(String format, Object... arguments) {
+        logger.info(format, arguments);
+    }
+
+    @Override
+    public void info(String msg, Throwable e) {
+        logger.info(msg, e);
+    }
+
+    @Override
+    public void warn(String format, Object... arguments) {
+        logger.warn(format, arguments);
+    }
+
+    @Override
+    public void warn(String msg, Throwable e) {
+        logger.warn(msg, e);
+    }
+
+    @Override
+    public void trace(String format, Object... arguments) {
+        logger.trace(format, arguments);
+    }
+
+    @Override
+    public void trace(String msg, Throwable e) {
+        logger.trace(msg, e);
+    }
+
+    @Override
+    public void debug(String format, Object... arguments) {
+        logger.debug(format, arguments);
+    }
+
+    @Override
+    public void debug(String msg, Throwable e) {
+        logger.debug(msg, e);
+    }
+
+    @Override
+    public void error(String format, Object... arguments) {
+        logger.error(format, arguments);
+    }
+
+    @Override
+    public void error(String msg, Throwable e) {
+        logger.error(msg, e);
+    }
+
+}

sentinel-extension/sentinel-logging-extension-slf4j/src/main/resources/META-INF/services/com.alibaba.csp.sentinel.log.Logger

@@ -0,0 +1,2 @@
+com.alibaba.csp.sentinel.logging.slf4j.RecordLogLogger
+com.alibaba.csp.sentinel.logging.slf4j.CommandCenterLogLogger