CODEWITHSUNDEEP
google-app-engineloggingjava.util.logging
William
William

Reputation: 20196

How can I change the logging format in Google AppEngine

AppEngine uses JUL for its logging and I have configured the logging.properties file and reference to that in appengine-web.xml

The problem is that the format that AppEngine presents the data in the console log gets truncated after about 180 chars on each log line. And since a large part of that is taken up with the method and class name (including package) and date there isn't much of the actual log message that comes out.

I have tried to configure my own Formatter, both programatically and via logging.properties without luck.

I realise that I could push all my log through slf4j, logback or log4j but I believe that doing so causes all such log to appear as stdout in the AppEngine log console which has its own style of verbosity.

Is there a way to define a particular format for the AppEngine log and if so how? t would be enough if each log line wasn't getting truncated to 180 chars.

Upvotes: 9

Views: 1873

Answers (3)

Greg Pastik
Greg Pastik

Reputation: 81

Looking through the source code for the App engine configuration tool itself, I have seen that all it is doing it calling the same LogService which you would have access to yourself through the LogService API.

Therefore, the answer to your question really is as simple as dropping the code from the following link into your code base, securing it to only the Admin user and problem solved.

https://developers.google.com/appengine/docs/java/logservice/overview

Upvotes: 0

Greg Pastik
Greg Pastik

Reputation: 81

Have you tried using the log download feature: It does not truncate the logs, you get to see everything, and can specify the number of days and severity of which log entries to download.

C:\eclipse\plugins\com.google.appengine.eclipse.sdkbundle_1.7.2.1\appengine-java-sdk-1.7.2.1\bin>appcfg.cmd --severity=DEBUG --num_days=2 request_logs C:\workspace\my_app\war C:\workspace\MY_LOGS.TXT

<path to SDK>/appcfg.cmd --severity=DEBUG --num_days=2 request_logs <path to war> <path to log>

That is the only way I found to be able to see my log details. The default log level is INFO, so you really have to use the severity and num_days arguments for it to be useful.

Additionally, if you want to download the logs for a backend, then you need to specify the backend version using the following option on the command line. Where worker is the name of the backend.

 --version=worker

Upvotes: 3

sappenin
sappenin

Reputation: 225

After digging into this a bit further, I couldn't get a custom JUL Handler or Formatter to get picked up by the appengine runtime. So instead, I created a ServletContextListener to initialize the root logger with my own custom formatter, as follows:

<listener>
   <listener-class>MyLoggingListener</listener-class>
</listener>

Here's a sample ServletContextListener:

public class MyLoggingListener implements ServletContextListener
{
    private static Logger LOG;

    @Override
    public void contextInitialized(ServletContextEvent sce)
    {
        LOG = Logger.getLogger("");
        Handler[] handlers = LOG.getHandlers();
        for (Handler handler : handlers)
        {
            handler.setFormatter(new MyLogFormatter());
        }
    }

    @Override
    public void contextDestroyed(ServletContextEvent sce)
    {}
}

Update: The above code works in the Dev Environment, but seems to be ignored on Appengine. Back to the drawing board on this one.

Upvotes: 0

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