Polish logging SPI related code and add general JUL adapter for Logge…

…r SPI

* Move the legacy JUL methods from LogBase to BaseJulLogger.
* Add a JavaLoggingAdapter as the general JUL adapter for the Logger SPI, which makes it convenient to use (as the default logger).
* Add LoggerSpiProvider to resolve Logger SPI.
* Polish the logback demo.

Signed-off-by: Eric Zhao <sczyh16@gmail.com>

sentinel-core/src/main/java/com/alibaba/csp/sentinel/log/CommandCenterLog.java

@@ -15,77 +15,73 @@
  */
 package com.alibaba.csp.sentinel.log;
 
-import java.util.Iterator;
-import java.util.ServiceLoader;
+import com.alibaba.csp.sentinel.log.jul.JavaLoggingAdapter;
 
 /**
  * Logger for command center.
+ *
+ * @author Eric Zhao
  */
 public class CommandCenterLog {
-    private static com.alibaba.csp.sentinel.log.Logger log = null;
+
+    public static final String LOGGER_NAME = "sentinelCommandCenterLogger";
+    public static final String DEFAULT_LOG_FILENAME = "command-center.log";
+
+    private static com.alibaba.csp.sentinel.log.Logger logger = null;
 
     static {
-        ServiceLoader<Logger> load = ServiceLoader.load(Logger.class);
-        Logger logger = null;
-        Iterator<Logger> iterator = load.iterator();
-        while (iterator.hasNext()) {
-            Logger next = iterator.next();
-            LogTarget annotation = next.getClass().getAnnotation(LogTarget.class);
-            if (annotation == null) {
-                continue;
+        try {
+            // Load user-defined logger implementation first.
+            logger = LoggerSpiProvider.getLogger(LOGGER_NAME);
+            if (logger == null) {
+                // If no customized loggers are provided, we use the default logger based on JUL.
+                logger = new JavaLoggingAdapter(LOGGER_NAME, DEFAULT_LOG_FILENAME);
             }
-            String value = annotation.value().name();
-            if (value.equals(LogType.COMMAND_CENTER_LOG.name())) {
-                logger = next;
-                break;
-            }
-        }
-        // Use user implementations.
-        if (logger != null) {
-            log = logger;
-        } else {
-            // Use default implementations.
-            log = new CommandCenterLogLogging();
+        } catch (Throwable t) {
+            System.err.println("Error: failed to initialize Sentinel CommandCenterLog");
+            t.printStackTrace();
         }
     }
 
     public static void info(String format, Object... arguments) {
-        log.info(format, arguments);
+        logger.info(format, arguments);
     }
 
     public static void info(String msg, Throwable e) {
-        log.info(msg, e);
+        logger.info(msg, e);
     }
 
     public static void warn(String format, Object... arguments) {
-        log.warn(format, arguments);
+        logger.warn(format, arguments);
     }
 
     public static void warn(String msg, Throwable e) {
-        log.warn(msg, e);
+        logger.warn(msg, e);
     }
 
     public static void trace(String format, Object... arguments) {
-        log.trace(format, arguments);
+        logger.trace(format, arguments);
     }
 
     public static void trace(String msg, Throwable e) {
-        log.trace(msg, e);
+        logger.trace(msg, e);
     }
 
     public static void debug(String format, Object... arguments) {
-        log.debug(format, arguments);
+        logger.debug(format, arguments);
     }
 
     public static void debug(String msg, Throwable e) {
-        log.debug(msg, e);
+        logger.debug(msg, e);
     }
 
     public static void error(String format, Object... arguments) {
-        log.error(format, arguments);
+        logger.error(format, arguments);
     }
 
     public static void error(String msg, Throwable e) {
-        log.error(msg, e);
+        logger.error(msg, e);
     }
+
+    private CommandCenterLog() {}
 }

sentinel-core/src/main/java/com/alibaba/csp/sentinel/log/LogBase.java

@@ -15,19 +15,14 @@
  */
 package com.alibaba.csp.sentinel.log;
 
-import com.alibaba.csp.sentinel.util.PidUtil;
 
 import java.io.File;
-import java.io.IOException;
 import java.util.Properties;
-import java.util.logging.Handler;
-import java.util.logging.Level;
-import java.util.logging.Logger;
 
 import static com.alibaba.csp.sentinel.util.ConfigUtil.addSeparator;
 
 /**
- * <p>The base class for logging.</p>
+ * <p>The base config class for logging.</p>
  *
  * <p>
  * The default log base directory is {@code ${user.home}/logs/csp/}. We can use the {@link #LOG_DIR}
@@ -36,7 +31,8 @@
  * In this case, {@link #LOG_NAME_USE_PID} property could be configured as "true" to turn on this switch.
  * </p>
  *
- * @author leyou
+ * @author Carpenter Lee
+ * @author Eric Zhao
  */
 public class LogBase {
 
@@ -66,15 +62,15 @@ public class LogBase {
 
     static {
         try {
-            initialize();
+            initializeDefault();
             loadProperties();
         } catch (Throwable t) {
-            System.err.println("[LogBase] FATAL ERROR when initializing log class");
+            System.err.println("[LogBase] FATAL ERROR when initializing logging config");
             t.printStackTrace();
         }
     }
 
-    private static void initialize() {
+    private static void initializeDefault() {
         logNameUsePid = false;
         logOutputType = LOG_OUTPUT_TYPE_FILE;
         logBaseDir = addSeparator(System.getProperty(USER_HOME)) + DIR_NAME + File.separator;
@@ -104,7 +100,6 @@ private static void loadProperties() {
         }
         System.out.println("INFO: log base dir is: " + logBaseDir);
 
-
         String usePid = properties.getProperty(LOG_NAME_USE_PID);
         logNameUsePid = "true".equalsIgnoreCase(usePid);
         System.out.println("INFO: log name use pid is: " + logNameUsePid);
@@ -147,64 +142,4 @@ public static String getLogCharset() {
         return logCharSet;
     }
 
-    protected static void log(Logger logger, Handler handler, Level level, String detail, Object... params) {
-        if (detail == null) {
-            return;
-        }
-        LoggerUtils.disableOtherHandlers(logger, handler);
-
-        FormattingTuple formattingTuple = MessageFormatter.arrayFormat(detail, params);
-        String message = formattingTuple.getMessage();
-        logger.log(level, message);
-    }
-
-    protected static void log(Logger logger, Handler handler, Level level, String detail, Throwable throwable) {
-        if (detail == null) {
-            return;
-        }
-        LoggerUtils.disableOtherHandlers(logger, handler);
-        logger.log(level, detail, throwable);
-    }
-
-
-    protected static Handler makeLogger(String logName, Logger heliumRecordLog) {
-        CspFormatter formatter = new CspFormatter();
-
-        Handler handler = null;
-
-        // Create handler according to logOutputType, set formatter to CspFormatter, set encoding to LOG_CHARSET
-        switch (logOutputType) {
-            case LOG_OUTPUT_TYPE_FILE:
-                String fileName = LogBase.getLogBaseDir() + logName;
-                if (isLogNameUsePid()) {
-                    fileName += ".pid" + PidUtil.getPid();
-                }
-                try {
-                    handler = new DateFileLogHandler(fileName + ".%d", 1024 * 1024 * 200, 4, true);
-                    handler.setFormatter(formatter);
-                    handler.setEncoding(logCharSet);
-                } catch (IOException e) {
-                    e.printStackTrace();
-                }
-                break;
-            case LOG_OUTPUT_TYPE_CONSOLE:
-                try {
-                    handler = new ConsoleHandler();
-                    handler.setFormatter(formatter);
-                    handler.setEncoding(logCharSet);
-                } catch (IOException e) {
-                    e.printStackTrace();
-                }
-                break;
-            default:
-                break;
-        }
-
-        if (handler != null) {
-            LoggerUtils.disableOtherHandlers(heliumRecordLog, handler);
-        }
-        heliumRecordLog.setLevel(Level.ALL);
-        return handler;
-    }
-
 }

sentinel-core/src/main/java/com/alibaba/csp/sentinel/log/LogTarget.java

@@ -19,14 +19,16 @@
 
 /**
  * @author xue8
+ * @since 1.7.2
  */
 @Retention(RetentionPolicy.RUNTIME)
 @Target(ElementType.TYPE)
 @Documented
 public @interface LogTarget {
     /**
-     * Returns the kinds of log type.
-     * @return Returns the kinds of log type
+     * Returns the logger name.
+     *
+     * @return the logger name. Record logger by default
      */
-    LogType value() default LogType.RECORD_LOG;
+    String value() default RecordLog.RECORD_LOGGER_NAME;
 }