[Mod-pubsub-developer] pubsub log4j appender

[<wsa...@ap...>]

FYI-

   Here's some code for a pubsub log4j appender, which means you can 
configure your logging to issue events.  This code calls the kn_publish 
command, so it's limited to machines with the C library installed.  You 
can easily change it to use KnowNow's Java library, but I didn't since 
it's not in the mod_pubsub package.

	-wsv


//
// PubSubAppender.java
//
// This class uses the kn_publish command provided by the C pubsub 
library.
// Ideally, it would use a Java pubsub library, but we don't have one 
yet.
//

import org.apache.log4j.*;
import org.apache.log4j.spi.*;
import org.apache.log4j.helpers.LogLog;

public class PubSubAppender extends AppenderSkeleton {

     public String getPubCommand      () { return pubCommand     ; }
     public String getPubSubServerURI () { return pubSubServerURI; }
     public String topic              () { return topic          ; }

     public void setPubCommand      (String value) { pubCommand      = 
value; }
     public void setPubSubServerURI (String value) { pubSubServerURI = 
value; }
     public void setTopic           (String value) { topic           = 
value; }

     private String pubCommand      = null;
     private String pubSubServerURI = null;
     private String topic           = null;

     public boolean requiresLayout () { return false; }

     public boolean ready () {
         if (! ready) {
             ready = true;
             if (pubCommand == null) {
                 LogLog.error("unable to locate publish command; can't 
send HTTP events.");
                 ready = false;
             }
             if (pubSubServerURI == null) {
                 LogLog.error("no server URI; can't send HTTP events.");
                 ready = false;
             }
             if (topic == null) {
                 LogLog.error("no topic; can't send HTTP events.");
                 ready = false;
             }
         }
         return ready;
     }
     private boolean ready = false;

     public void append (LoggingEvent event) {
         if (! ready()) return;

         String level            = event.getLevel().toString();
         String loggerName       = event.getLoggerName();
         String message          = event.getRenderedMessage();
         String startTime        = String.valueOf(event.getStartTime());
         String threadName       = event.getThreadName();
         String className        = "";
         String fileName         = "";
         String lineNumber       = "";
         String methodName       = "";
         String formattedMessage = (this.layout == null) ? "" : 
this.layout.format(event);

         LocationInfo locationInfo = event.getLocationInformation();

         if (locationInfo != null) {
             className  = locationInfo.getClassName();
             fileName   = locationInfo.getFileName();
             lineNumber = locationInfo.getLineNumber();
             methodName = locationInfo.getMethodName();
         }

         String command[] = new String[]{
             pubCommand,
             "-H", "level"            , level           ,
             "-H", "class"            , className       ,
             "-H", "file"             , fileName        ,
             "-H", "line"             , lineNumber      ,
             "-H", "method"           , methodName      ,
             "-H", "logger"           , loggerName      ,
             "-H", "message"          , message         ,
             "-H", "start time"       , startTime       ,
             "-H", "thread"           , threadName      ,
             "-H", "formatted message", formattedMessage,
             pubSubServerURI, topic, "/dev/null"
         };

         try {
             if (Runtime.getRuntime().exec(command).waitFor() != 0) {
                 LogLog.warn("unable to log event: " + 
event.getMessage());
             }
         } catch (Exception e) {
             LogLog.warn ("exception while logging event: " + 
event.getMessage());
             LogLog.error("exception while logging: " + e);
         }
     }

     public void close () {}
}