[Java] Logging

JohnnyD · Post by **JohnnyD** » 17 Nov 2007, 11:06

SF server writes things to log files, with severity level like INFO, WARN, ERROR, etc. Obviously there is functionality inside SF to do this; is this exposed so that I can use it from my Java extension? Is SF using Log4J internally or is this a custom logger the SF developers wrote?

Thanks.

Post by **Lapo** » 20 Nov 2007, 13:57

Yes you can. We don't use log4j, we use the java.util.logging package
If you use Actionscript we provide a specific object for logging (check the docs)
Under Java you can access the logger as a static member like this:

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SmartFoxServer.log.info("Hello!")

JohnnyD · Post by **JohnnyD** » 02 May 2008, 15:58

I never got round to using this, but now I need to. I can't find where the logger is stored (in Java). It sounds like there is one preconfigured I can use.

Post by **Lapo** » 03 May 2008, 16:15

Just as explained in the above code

log is a static member of the SmartFoxServer class.

If you want to configure differently you can check the logging.properties file in you Server/ folder

... and ... if you prefer using another logging system, just plug it into your server extension

JohnnyD · Post by **JohnnyD** » 03 May 2008, 20:05

Sorry but as far as I can see from your JavaDocs (http://www.smartfoxserver.com/docs/docP ... index.html) there is no SmartFoxServer class. And I can't see any SFS class with a log attribute. Am I missing something?

Post by **Lapo** » 04 May 2008, 06:03

Yes this is correct.
We are trying to avoid exposing all the classes in the javadocs and I admit it's not an easy task

We'd like to simplify the access to the framework as much as possible avoiding dozens of classes (with relative fields and methods) that developers will never use and that would just confuse them.

In doing this a few minor things have escaped (the logger is one) but the support board is here just for this sort of issues.

Hope it helps

Boing · Post by **Boing** » 30 Jul 2008, 13:59

Hi!
I use Log4J for logging my own stuff but I would like to find the SFS log output in the same file. Is there a way to intercept the SFS logging?

Boing · Post by **Boing** » 30 Jul 2008, 14:11

I just came across this possibility:

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SmartFoxServer.log.addHandler(new MyHandler());

I'll try that and post the result...

Boing · Post by **Boing** » 30 Jul 2008, 15:24

It's actually quite easy. For those who are interested I post my utility class:

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public class SFSLog4JLogger extends java.util.logging.Handler {

    
    private static final org.apache.log4j.Logger log =
                         org.apache.log4j.Logger.getLogger(SFSLog4JLogger.class);

    
    @Override
    public void close() throws SecurityException {}

    @Override
    public void flush() {}

    @Override
    public void publish(final java.util.logging.LogRecord record) {

        // build msg (get more info out of the record if you like to)
        String msg = record.getMessage();

        // find level
        org.apache.log4j.Level level = org.apache.log4j.Level.INFO;

        if (java.util.logging.Level.SEVERE.equals(record.getLevel())) {
            level = org.apache.log4j.Level.ERROR;
            
        } else if (java.util.logging.Level.WARNING.equals(record.getLevel())) {
            level = org.apache.log4j.Level.WARN;
            
        } else if (java.util.logging.Level.INFO.equals(record.getLevel()) ||
                   java.util.logging.Level.CONFIG.equals(record.getLevel())) {
            level = org.apache.log4j.Level.INFO;
            
        } else if (java.util.logging.Level.FINE.equals(record.getLevel()) ||
                   java.util.logging.Level.FINER.equals(record.getLevel())) {
            level = org.apache.log4j.Level.DEBUG;
            
        } else if (java.util.logging.Level.FINEST.equals(record.getLevel())) {
            level = org.apache.log4j.Level.TRACE;
        }        

        // log
        log.log(record.getSourceClassName(), level, msg, record.getThrown());
    }
    
}

Having that you just need to call

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SmartFoxServer.log.addHandler(new SFSLog4JLogger());

at program startup.

Post by **Lapo** » 30 Jul 2008, 19:46

Interesting, thanks for posting.

ffratoni · Post by **ffratoni** » 15 Sep 2008, 15:16

Do you have a best practice to handle async logging other than using the Log4j Async appender thorough log4j logger?

Post by **Lapo** » 15 Sep 2008, 15:54

What is asynch logging?
Thanks

ffratoni · Post by **ffratoni** » 16 Sep 2008, 09:28

asynchronous logging that in common logging is usually handled by
AsyncAppender.
Have you any best practice to avoid "in process logging" and process blocking or using the Log4JHandler with AsyncAppender is the recommended way?
Is there a built-in way to persist events on DB(for logging needs)?
Filippo

Post by **Lapo** » 16 Sep 2008, 11:33

I see, put in simple words ... you're going to log to a potentially "slow" device (i.e. the DB) and wish to avoid blocking the current thread... right?

We don't have a best practice for this, and I've never used asynchronous logging myself, so I am not able to help here.
If Log4J helps in this regards it would probably be ok to use it.

An alternative is to add more threads to the ExtensionHandler stage of the server (see chapter 2.2). This way you don't incur into problems with "slow" operations.

Cheers

ffratoni · Post by **ffratoni** » 16 Sep 2008, 14:34

Exactly
Due to the amount of events to log we probably need decouple log operation
from business processes.
Thanks for the answer
Filippo

[Java] Logging

[Java] Logging

redirect SFS logging to Log4J

async logging

asynchronous logging