Add support for logging into console for common logs (alibaba#836)

* Add a ConsoleHandler to support logging into stdout and stderr.
* Add a `csp.sentinel.log.output.type` property to configure for output type of record logs (only a temporary design)
* Add millisecond to the format of CspFormatter

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

@@ -0,0 +1,85 @@
+/*
+ * 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.log;
+
+import java.io.UnsupportedEncodingException;
+import java.util.logging.*;
+
+/**
+ * This Handler publishes log records to console by using {@link java.util.logging.StreamHandler}.
+ *
+ * Print log of WARNING level or above to System.err,
+ * and print log of INFO level or below to System.out.
+ *
+ * To use this handler, add the following VM argument:
+ * <pre>
+ * -Dcsp.sentinel.log.output.type=console
+ * </pre>
+ *
+ * @author cdfive
+ */
+class ConsoleHandler extends Handler {
+
+    /**
+     * A Handler which publishes log records to System.out.
+     */
+    private StreamHandler stdoutHandler;
+
+    /**
+     * A Handler which publishes log records to System.err.
+     */
+    private StreamHandler stderrHandler;
+
+    public ConsoleHandler() {
+        this.stdoutHandler = new StreamHandler(System.out, new CspFormatter());
+        this.stderrHandler = new StreamHandler(System.err, new CspFormatter());
+    }
+
+    @Override
+    public synchronized void setFormatter(Formatter newFormatter) throws SecurityException {
+        this.stdoutHandler.setFormatter(newFormatter);
+        this.stderrHandler.setFormatter(newFormatter);
+    }
+
+    @Override
+    public synchronized void setEncoding(String encoding) throws SecurityException, UnsupportedEncodingException {
+        this.stdoutHandler.setEncoding(encoding);
+        this.stderrHandler.setEncoding(encoding);
+    }
+
+    @Override
+    public void publish(LogRecord record) {
+        if (record.getLevel().intValue() >= Level.WARNING.intValue()) {
+            stderrHandler.publish(record);
+            stderrHandler.flush();
+        } else {
+            stdoutHandler.publish(record);
+            stdoutHandler.flush();
+        }
+    }
+
+    @Override
+    public void flush() {
+        stdoutHandler.flush();
+        stderrHandler.flush();
+    }
+
+    @Override
+    public void close() throws SecurityException {
+        stdoutHandler.close();
+        stderrHandler.close();
+    }
+}

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

@@ -28,7 +28,7 @@ class CspFormatter extends Formatter {
     private final ThreadLocal<SimpleDateFormat> dateFormatThreadLocal = new ThreadLocal<SimpleDateFormat>() {
         @Override
         public SimpleDateFormat initialValue() {
-            return new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
+            return new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS");
         }
     };
 
@@ -37,6 +37,7 @@ public String format(LogRecord record) {
         final DateFormat df = dateFormatThreadLocal.get();
         StringBuilder builder = new StringBuilder(1000);
         builder.append(df.format(new Date(record.getMillis()))).append(" ");
+        builder.append(record.getLevel().getName()).append(" ");
         builder.append(formatMessage(record));
 
         String throwable = "";

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

@@ -22,6 +22,7 @@
 import java.util.logging.Logger;
 
 import com.alibaba.csp.sentinel.util.PidUtil;
+import com.alibaba.csp.sentinel.util.StringUtil;
 
 /**
  * Default log base dir is ${user.home}/logs/csp/, we can use {@link #LOG_DIR} System property to override it.
@@ -35,15 +36,22 @@ public class LogBase {
 
     public static final String LOG_CHARSET = "utf-8";
 
+    // Output biz log(RecordLog,CommandCenterLog) to file
+    public static final String LOG_OUTPUT_TYPE_FILE = "file";
+    // Output biz log(RecordLog,CommandCenterLog) to console
+    public static final String LOG_OUTPUT_TYPE_CONSOLE = "console";
+
     private static final String DIR_NAME = "logs" + File.separator + "csp";
     private static final String USER_HOME = "user.home";
 
+    // Output type of biz log(RecordLog,CommandCenterLog)
+    public static final String LOG_OUTPUT_TYPE = "csp.sentinel.log.output.type";
     public static final String LOG_DIR = "csp.sentinel.log.dir";
     public static final String LOG_NAME_USE_PID = "csp.sentinel.log.use.pid";
 
-    private static boolean logNameUsePid = false;
-
+    private static String logOutputType;
     private static String logBaseDir;
+    private static boolean logNameUsePid = false;
 
     static {
         try {
@@ -55,6 +63,15 @@ public class LogBase {
     }
 
     private static void init() {
+        logOutputType = System.getProperty(LOG_OUTPUT_TYPE);
+
+        // By default, output biz log(RecordLog,CommandCenterLog) to file
+        if (StringUtil.isBlank(logOutputType)) {
+            logOutputType = LOG_OUTPUT_TYPE_FILE;
+        } else if (!LOG_OUTPUT_TYPE_FILE.equalsIgnoreCase(logOutputType) && !LOG_OUTPUT_TYPE_CONSOLE.equalsIgnoreCase(logOutputType)) {
+            logOutputType = LOG_OUTPUT_TYPE_FILE;
+        }
+
         // first use -D, then use user home.
         String logDir = System.getProperty(LOG_DIR);
 
@@ -125,18 +142,37 @@ public static String getLogBaseDir() {
 
     protected static Handler makeLogger(String logName, Logger heliumRecordLog) {
         CspFormatter formatter = new CspFormatter();
-        String fileName = LogBase.getLogBaseDir() + logName;
-        if (isLogNameUsePid()) {
-            fileName += ".pid" + PidUtil.getPid();
-        }
+
         Handler handler = null;
-        try {
-            handler = new DateFileLogHandler(fileName + ".%d", 1024 * 1024 * 200, 4, true);
-            handler.setFormatter(formatter);
-            handler.setEncoding(LOG_CHARSET);
-        } catch (IOException e) {
-            e.printStackTrace();
+
+        // 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(LOG_CHARSET);
+                } catch (IOException e) {
+                    e.printStackTrace();
+                }
+                break;
+            case LOG_OUTPUT_TYPE_CONSOLE:
+                try {
+                    handler = new ConsoleHandler();
+                    handler.setFormatter(formatter);
+                    handler.setEncoding(LOG_CHARSET);
+                } catch (IOException e) {
+                    e.printStackTrace();
+                }
+                break;
+            default:
+                break;
         }
+
         if (handler != null) {
             LoggerUtils.disableOtherHandlers(heliumRecordLog, handler);
         }

sentinel-core/src/test/java/com/alibaba/csp/sentinel/log/ConsoleHandlerTest.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.log;
+
+import org.junit.Test;
+
+import java.io.ByteArrayOutputStream;
+import java.io.PrintStream;
+import java.util.logging.Level;
+import java.util.logging.LogRecord;
+
+import static org.junit.Assert.*;
+
+/**
+ * Test cases for {@link ConsoleHandler}.
+ *
+ * @author cdfive
+ */
+public class ConsoleHandlerTest {
+
+    @Test
+    public void testPublish() {
+        ByteArrayOutputStream baosOut = new ByteArrayOutputStream();
+        System.setOut(new PrintStream(baosOut));
+
+        ByteArrayOutputStream baosErr = new ByteArrayOutputStream();
+        System.setErr(new PrintStream(baosErr));
+
+        CspFormatter cspFormatter = new CspFormatter();
+        ConsoleHandler consoleHandler = new ConsoleHandler();
+
+        LogRecord logRecord;
+
+        // Test INFO level, should log to stdout
+        logRecord = new LogRecord(Level.INFO, "test info message");
+        consoleHandler.publish(logRecord);
+        assertEquals(cspFormatter.format(logRecord), baosOut.toString());
+        assertEquals("", baosErr.toString());
+        baosOut.reset();
+        baosErr.reset();
+
+        // Test INFO level, should log to stderr
+        logRecord = new LogRecord(Level.WARNING, "test warning message");
+        consoleHandler.publish(logRecord);
+        assertEquals(cspFormatter.format(logRecord), baosErr.toString());
+        assertEquals("", baosOut.toString());
+        baosOut.reset();
+        baosErr.reset();
+
+        // Test FINE level, no log by default
+        // Default log level is INFO, to log FINE message to stdout, add following config in $JAVA_HOME/jre/lib/logging.properties
+        // java.util.logging.StreamHandler.level=FINE
+        logRecord = new LogRecord(Level.FINE, "test fine message");
+        consoleHandler.publish(logRecord);
+        assertEquals("", baosOut.toString());
+        assertEquals("", baosErr.toString());
+        baosOut.reset();
+        baosErr.reset();
+
+        // Test SEVERE level, should log to stderr
+        logRecord = new LogRecord(Level.SEVERE, "test severe message");
+        consoleHandler.publish(logRecord);
+        assertEquals(cspFormatter.format(logRecord), baosErr.toString());
+        assertEquals("", baosOut.toString());
+        baosOut.reset();
+        baosErr.reset();
+    }
+}