i just created my own appender as base of Logback document chapter 4 (see Writing your own Appender section).
Whatever is being logged at INFO level in my application, My appender gets invoked and post that message as http message to the servlet running on other end.
these kind of logic makes my application to slow down. because the appender runs on same thread which application is running. How do i make my appender to run in separate thread ?
Since Logback is based on Log4J, you should be able to used asynchronous logging option. See here This makes sure that your logging process runs in a separate thread.
Related
I am working on enabling Async logger with our service. We have observed that whenever there is an excessive logging, async logger starts blocking application threads. After going through docs of Async logger, we came to know that it can be avoided by dropping log message event.
My query is, does log4j library logs any error message whenever a log message event gets dropped? Or if not, is there is a way to configure it to log such error messages.
EDIT:
I figured out I need to enable internal logging of log4j to log this statement. Now the issue I am facing is logging in our system is enabled using PropertyConfigurator. But I am unable to find a way to enable just WARN level logs for PropertyConfigurator. Any help?
I am working on a project and we are having the log level to Debug on in Java Mission Control I am seeing that under Top Blocking Locks I have a class org.apache.log4j.spi.RootLogger. We have set our system to Error level and this class disappeared from the Blocking logs.
I am looking to implement AsyncAppender but I am not sure of the buffsize that I should give it. Also what happens if the buffsize is exceeded by the system. Will it just not write the logs or will it crash ? I am using a property file called log4j.properties in which I have
log4j.appender.CONSOLE_C=org.apache.log4j.ConsoleAppender
How would I add an AsyncAppender and the buffsize?
I am developing an Eclipse RCP application and have gone to some pains to get log4j2 to work within the app. All seems to work fine now, and as a finishing touch I wanted to make all loggers asynchronously.
I've managed to get the LMAX Disruptor on the classpath, and think I've solved the issue of providing sun.misc as well. Set the VM argument -DLog4jContextSelector=org.apache.logging.log4j.core.async.AsyncLoggerContextSelector in the run config and set up log4j2.xml file correctly as well. I think. And that's where the problem is. I'd like to be able to verify that my application logs asynchronously in the proper fashion, so I can enjoy the benefits latency-wise.
How can I - then - verify that my loggers are working asynchronously, utilising the LMAX Dirsuptor in the process?
There are two types of async logger, handled by different classes.
All loggers async: the AsyncLogger class - activated when you use AsyncLoggerContextSelector
Mixing sync with async loggers: the AsyncLoggerConfig class - when your configuration file has <AsyncRoot> or <AsyncLogger> elements nested in the configuration for <Loggers>.
In your case you are making all loggers async, so you want to put your breakpoint in AsyncLogger#logMessage(String, Level, Marker, Message, Throwable).
Another way to verify is by setting <Configuration status="trace"> at the top of your configuration file. This will output internal log4j log messages on log4j is configured. You should see something like "Starting AsyncLogger disruptor...". If you see this all loggers are async.
Put a breakpoint in org.apache.logging.log4j.core.async.AsyncLoggerConfig#callAppenders. Then you can watch as the event is put into the disruptor. Likewise org.apache.logging.log4j.core.config.LoggerConfig#callAppenders should be getting hit for synchronous logging OR getting hit from the other side of the disruptor for async logging (at which point everything is synchronous again).
In a multithreaded environment (web service provider) I need to create log entries in a database per request (normally per thread). What is the approach to use for something like this?
Same logger for all threads and create an appender per thread. Then at the end of the request/thread close/remove the appender.
A logger per thread (different class name per thread). At the end of the request/thread somehow release the specific logger
Other?
From an Apache log4j FAQ:
Yes, log4j is thread-safe. Log4j components are designed to be used in heavily multithreaded systems.
As Marko Topolnik comments, just ignore multithreading when planning your logging statements, and let log4j take care of it.
I'm new to logback. I quite fascinated by it but I'm not sure if it suits my use-case.
I would like to have a logger that I can stop and start. While it is stopped I would like to remove the log file from the filesystem. When logging is restarted the file should be re-created.
Is logback capable of this? While the logging is paused, should I avoid calling a Logger in my classes, or can logback handle this?
I use a slf4j.Logger currently. In the manual I saw that Appender objects implement the LifeCycle interface, which implies that they implement start(), stop() and isStarted().
I thought this means they can be stopped so I can move the file, but later on it goes:
If the appender could not be started or if it has been stopped, a
warning message will be issued through logback's internal status
management system. After several attempts, in order to avoid flooding
the internal status system with copies of the same warning message,
the doAppend() method will stop issuing these warnings.
Does it mean that I can stop it, then remove the file, then restart?
I would like to have a logger that I can stop and start. While it is stopped I would like to remove the log file from the filesystem. When logging is restarted the file should be re-created.
I'm not sure how to accomplish this programmatically but you can accomplish this via JMX if you've added jmxConfigurator to the logback.xml config file.
<configuration>
<jmxConfigurator />
...
This exposes the ch.qos.logback.classic.jmx.JMXConfigurator bean which has an operation entitled reloadDefaultConfiguration. When I press that at runtime, the logfiles are reopened. See Jconsole image below. This means that a jmx client (such as the one in my SimpleJMX library for example) would be able to do that from the command line.
If you are trying to it programmatically from inside of the same application then you should be able to get ahold of the mbean and trigger the call yourself. Something like seems to work for me:
ManagementFactory.getPlatformMBeanServer().invoke(new ObjectName(
"ch.qos.logback.classic:Name=default,Type=ch.qos.logback.classic.jmx.JMXConfigurator"),
"reloadDefaultConfiguration", null, null);
What I would do is rename the logfile(s) to a different name(s) and then issue the reload configuration command. Then the renamed files can be archived or removed after the new files are created.
Hope this helps.