Added -log_dir option.

Added some logic to append to an existing log4j configuration (used by the Sparkling Water case).

h2o-core/src/main/java/org/apache/log4j/H2OPropertyConfigurator.java

@@ -0,0 +1,17 @@
+package org.apache.log4j;
+
+import org.apache.log4j.spi.LoggerRepository;
+
+import java.util.Properties;
+
+public class H2OPropertyConfigurator extends PropertyConfigurator {
+  @Override
+  public
+  void doConfigure(Properties properties, LoggerRepository hierarchy) {
+    parseCatsAndRenderers(properties, hierarchy);
+
+    // We don't want to hold references to appenders preventing their
+    // garbage collection.
+    registry.clear();
+  }
+}

h2o-core/src/main/java/water/H2O.java

@@ -99,6 +99,10 @@ public static void printHelp() {
             "    -ice_root <fileSystemPath>\n" +
             "          The directory where H2O spills temporary data to disk.\n" +
             "\n" +
+            "    -log_dir <fileSystemPath>\n" +
+            "          The directory where H2O writes logs to disk.\n" +
+            "          (This usually has a good default that you need not change.)\n" +
+            "\n" +
             "    -flow_dir <server side directory or hdfs directory>\n" +
             "          The directory where H2O stores saved flows.\n" +
             defaultFlowDirMessage +
@@ -191,6 +195,9 @@ public static class OptArgs {
     /** -nthreads=nthreads; Max number of F/J threads in the low-priority batch queue */
     public int nthreads=Runtime.getRuntime().availableProcessors();
 
+    /** -log_dir=/path/to/dir; directory to save logs in */
+    public String log_dir;
+
     /** -flow_dir=/path/to/dir; directory to save flows in */
     public String flow_dir;
 
@@ -372,6 +379,10 @@ else if (s.matches("ice_root")) {
         i = s.incrementAndCheck(i, args);
         ARGS.ice_root = args[i];
       }
+      else if (s.matches("log_dir")) {
+        i = s.incrementAndCheck(i, args);
+        ARGS.log_dir = args[i];
+      }
       else if (s.matches("flow_dir")) {
         i = s.incrementAndCheck(i, args);
         ARGS.flow_dir = args[i];

h2o-core/src/main/java/water/util/Log.java

@@ -2,6 +2,8 @@
 
 import java.io.File;
 import java.util.ArrayList;
+
+import org.apache.log4j.H2OPropertyConfigurator;
 import org.apache.log4j.LogManager;
 import org.apache.log4j.PropertyConfigurator;
 import water.H2O;
@@ -202,8 +204,8 @@ public static String getLogFileName(String level) throws Exception {
     return getLogFileNameStem() + f;
   }
 
-  private static void setLog4jProperties(String logDirParent, java.util.Properties p) throws Exception {
-    LOG_DIR = logDirParent + File.separator + "h2ologs";
+  private static void setLog4jProperties(String logDir, java.util.Properties p) throws Exception {
+    LOG_DIR = logDir;
     String logPathFileName = getLogPathFileNameStem();
 
     // H2O-wide logging
@@ -288,33 +290,35 @@ private static void setLog4jProperties(String logDirParent, java.util.Properties
   private static synchronized org.apache.log4j.Logger createLog4j() {
     if( _logger != null ) return _logger; // Test again under lock
 
-    // Create some default properties on the fly if we aren't using a provided configuration.
     boolean launchedWithHadoopJar = H2O.ARGS.hdfs_skip;
-    String log4jConfiguration = System.getProperty ("log4j.configuration");
+    String log4jConfiguration = System.getProperty ("h2o.log4j.configuration");
     boolean log4jConfigurationProvided = log4jConfiguration != null;
 
-    // Note: for the hadoop case, force H2O to specify the logging setup since we don't care
-    // about any hadoop log setup, anyway.
-    if (!launchedWithHadoopJar && H2O.haveInheritedLog4jConfiguration()) {
-      // Do nothing.
-    }
-    else if (!launchedWithHadoopJar && log4jConfigurationProvided) {
+    if (log4jConfigurationProvided) {
       PropertyConfigurator.configure(log4jConfiguration);
     }
     else {
+      // Create some default properties on the fly if we aren't using a provided configuration.
       // H2O creates the log setup itself on the fly in code.
       java.util.Properties p = new java.util.Properties();
       try {
         File dir;
-        boolean windowsPath = H2O.ICE_ROOT.toString().matches("^[a-zA-Z]:.*");
-
-        // Use ice folder if local, or default
-        if (windowsPath)
-          dir = new File(H2O.ICE_ROOT.toString());
-        else if( H2O.ICE_ROOT.getScheme() == null || PersistManager.Schemes.FILE.equals(H2O.ICE_ROOT.getScheme()) )
-          dir = new File(H2O.ICE_ROOT.getPath());
-        else
-          dir = new File(H2O.DEFAULT_ICE_ROOT());
+        if (H2O.ARGS.log_dir != null) {
+          dir = new File(H2O.ARGS.log_dir);
+        }
+        else {
+          boolean windowsPath = H2O.ICE_ROOT.toString().matches("^[a-zA-Z]:.*");
+
+          // Use ice folder if local, or default
+          if (windowsPath)
+            dir = new File(H2O.ICE_ROOT.toString());
+          else if (H2O.ICE_ROOT.getScheme() == null || PersistManager.Schemes.FILE.equals(H2O.ICE_ROOT.getScheme()))
+            dir = new File(H2O.ICE_ROOT.getPath());
+          else
+            dir = new File(H2O.DEFAULT_ICE_ROOT());
+
+          dir = new File(dir, "h2ologs");
+        }
 
         setLog4jProperties(dir.toString(), p);
       }
@@ -323,7 +327,19 @@ else if( H2O.ICE_ROOT.getScheme() == null || PersistManager.Schemes.FILE.equals(
         e.printStackTrace();
         H2O.exit(1);
       }
-      PropertyConfigurator.configure(p);
+
+      // For the Hadoop case, force H2O to specify the logging setup since we don't care
+      // about any hadoop log setup, anyway.
+      //
+      // For the Sparkling Water case, we will have inherited the log4j configuration,
+      // so append to it rather than whack it.
+      if (!launchedWithHadoopJar && H2O.haveInheritedLog4jConfiguration()) {
+        // Use a modified log4j property configurator to append rather than create a new log4j configuration.
+        H2OPropertyConfigurator.configure(p);
+      }
+      else {
+        PropertyConfigurator.configure(p);
+      }
     }
 
     return (_logger = LogManager.getLogger("water.default"));