log4j on the kindle

[dragon123]

Hi,

I hope someone can help me. I'm trying to log some output of my kindlet, but I didn't get any log file. I tried two versions of my propertie file, but it didn't work. So what could be wrong? Is the propertie file not correct? In which directory it should be on the kindle?

Could anyone help me please? Thanks in advance.

The code of the programm is:

package kindlebeispiel;

import com.amazon.kindle.kindlet.AbstractKindlet;
import com.amazon.kindle.kindlet.KindletContext;
import com.amazon.kindle.kindlet.ui.KTextArea;

import org.apache.log4j.Logger;

public class Main extends AbstractKindlet {
    
    private static final Logger log = Logger.getLogger(Main.class);
    
    public void create(KindletContext context) {
        log.debug("test1");
        this.ctx = context;
    }

    public void start() {
        try {
            log.debug("test2");
            ctx.getRootContainer().add(new KTextArea("Hello World"));
        } catch (Throwable t) {
            t.printStackTrace();
        }
    }

    public void stop() {
    }

    public void destroy() {
    }
}

The code of the properties files is:

log4j.rootLogger=DEBUG
log4j.appender.R=org.apache.log4j.FileAppender
log4j.appender.R.File=log4j.log
log4j.appender.R.layout=org.apache.log4j.PatternLayout
log4j.appender.R.layout.ConversionPattern=%p %t %c - %m%n

log4j.rootLogger=debug, R

log4j.category.kindle.KindleTerminal=info
log4j.category.kindle.KindleTerminal$Redrawer=warn

log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout

# Pattern to output the caller's file name and line number.
log4j.appender.stdout.layout.ConversionPattern=%5p [%t] (%F:%L) - %m%n

log4j.appender.R=org.apache.log4j.RollingFileAppender
log4j.appender.R.File=/mnt/us/developer/kindlebeispiel/work/kindlebeispiel.log

log4j.appender.R.MaxFileSize=100KB
# Keep one backup file
log4j.appender.R.MaxBackupIndex=1

log4j.appender.R.layout=org.apache.log4j.PatternLayout
log4j.appender.R.layout.ConversionPattern=%d{dd MMM HH:mm:ss} %5p [%t] (%F:%L) - %m%n

[knc1]

check if logging is disabled at a system's level.

seems to me that was the problem (and solution) last time someone asked about this.

[dragon123]

Sorry for the stupid question, but I haven't the KDK.

Where can I check that logging is disabled? Can you tell me the path please.

[aditya3098]

If the thing logs to a file, you will need a kindle jailbreak. See the kual sticky prereqs. Note that you cannot publish to amazon if you've used the kindlet jb

[knc1]

Originally Posted by dragon123

Sorry for the stupid question, but I haven't the KDK.

Where can I check that logging is disabled? Can you tell me the path please.

What are you running the Kindlet on?
Check that system's logging settings.

PS: Nobody has (or at least uses) the KDK here.

[ixtab]

@dragon123: You're not providing enough information. Are you getting an error? If so, which? Did you bundle log4j with your application, or make sure that log4j is actually supported?

The actual file that you want to be logging to seems ok, i.e., that directory should be accessible and writable from a Kindlet without the Kindlet jailbreak.

Still, I think that log4j is a massive overkill for what you're trying to do. If all you want to do is output some text to a file, I suggest to simply write an extremely simple Logging utility yourself.

I'm using this trivial peace of code in JBPatch. You could of course create something more prowerful, with logging levels etc. - but it will still be MUCH less complicated than using a full-blown logging framework like log4j.

[bhaak]

Originally Posted by dragon123

I hope someone can help me. I'm trying to log some output of my kindlet, but I didn't get any log file. I tried two versions of my propertie file, but it didn't work. So what could be wrong? Is the propertie file not correct? In which directory it should be on the kindle?

My guess is that the properties file doesn't get read and your log4j logger isn't initialized at all. Have you any log4j experience? Sometimes it can be tricky to get it to output anything

In my HackedUpReaderKindlet I'm putting the log4j.properties into the same directory in the azw2 file as the other class files and I am loading it manually. You can have a look at it on github: https://github.com/bhaak/HackedUpRea...erKindlet.java

[bhaak]

Originally Posted by ixtab

@dragon123: You're not providing enough information. Are you getting an error? If so, which? Did you bundle log4j with your application, or make sure that log4j is actually supported?

log4j is already on the Kindle at /opt/amazon/ebook/sdk/lib/log4j-1.2.16.jar and it works well when configured properly when writing to the allowed locations (/mnt/us/developer/kindlet_name/work/*).

Originally Posted by ixtab

Still, I think that log4j is a massive overkill for what you're trying to do. If all you want to do is output some text to a file, I suggest to simply write an extremely simple Logging utility yourself.

I'm using this trivial peace of code in JBPatch. You could of course create something more prowerful, with logging levels etc. - but it will still be MUCH less complicated than using a full-blown logging framework like log4j.

Why not using a standard solution instead of writing an inferior version yourself? Logging seems trivial but you quickly get into difficult waters. Log levels seem easy enough but what about rotating log files or multiple log files (I usually configure log4j to output errors also into a separate file)?

[ixtab]

Originally Posted by bhaak

log4j is already on the Kindle at /opt/amazon/ebook/sdk/lib/log4j-1.2.16.jar and it works well when configured properly when writing to the allowed locations (/mnt/us/developer/kindlet_name/work/*).

Why not using a standard solution instead of writing an inferior version yourself? Logging seems trivial but you quickly get into difficult waters. Log levels seem easy enough but what about rotating log files or multiple log files (I usually configure log4j to output errors also into a separate file)?

You're correct of course. I didn't even realize that the Kindles came with log4j preinstalled - so yeah, in that case your answer is probably what the OP is looking for.

That said, I personally dislike log4j for reasons I can't really explain... maybe I'm spoilt by past experiences with it.

... And IMO, the usual Kindlet isn't exactly a complex application server that requires extensive logging with 7 different log levels, log file rotation etc. As the saying goes: "use the right tools for the right job". In my particular case, the trivial solution was enough. In other cases, a more complex and powerful solution may be better.