...can we do better?: Log4j

Showing posts with label Log4j. Show all posts

Wednesday, April 1, 2015

log4j2: line separator in header's parameter of PatternLayout

Log4j2 provides a new parameter for PatternLayout:

Parameter name: header
Type: String
Description: the optional header string to include at the top of each log file

With the following log4j2.xml configuration:

<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="WARN" monitorInterval="20">
    <Appenders>
        <RollingRandomAccessFile name="file" fileName="logs/app.log" filePattern="logs/app-%d_%i.log.gz">
            <PatternLayout>
                <header>
Version: ${env:APP_RELEASE_VERSION}
                </header>
                <pattern>%message%n</pattern>
            </PatternLayout>
            <Policies>
                <OnStartupTriggeringPolicy/>
            </Policies>
        </RollingRandomAccessFile>
    </Appenders>
    <Loggers>
        <Root level="debug">
            <AppenderRef ref="file"/>
        </Root>
    </Loggers>
</Configuration>

JLV v.1.3.3 has been released

Update site: https://github.com/rdiachenko/jlv/raw/repo/eclipse

Or Eclipse Marketplace: http://marketplace.eclipse.org/content/jlv

Release notes:

fixed problems with hanging on Windows OS
fixed null pointer exceptions related to loading and releasing resources
server part was improved
a new resource manager was provided

The main project's page: https://github.com/rdiachenko/jlv#information

Wednesday, October 26, 2011

Log4j: NDC/MDC

Nested Diagnostic Context (NDC) and Mapped Diagnostic Context (MDC) are used in cases when we want to distinguish logs from multiple threads by marking each log with thread specific information. NDC and MDC provide possibility to store some contextual information for each thread. But there's a difference in the way they do it.

NDC

Each thread has it's own context. NDC uses stack for pushing information when entering thread's context and popping it when leaving that context. This information is attached to log and can be displayed by using '%x' Pattern Layout option.

MDC

MDC uses map to store context information. It means that there must be a unique key associated with each piece of thread information. The information is attached to log and can be displayed by using '%X{key}' Pattern Layout option, where the key is an association with a value in the map.

Here you can find Log4j Pattern Layout option's description: http://logging.apache.org/log4j/1.2/apidocs/org/apache/log4j/PatternLayout.html

Tuesday, October 11, 2011

How to use SLF4J with Log4j

Today I will show you how to use SLF4J with Log4j on a simple example.

Let's start with Log4j. First, download log4j library and add log4j-1.2.16.jar into classpath.

Create log4j.properties file, which will contain log4j configuration and put it into project. It may look like this:

log4j.rootLogger=DEBUG, A1

log4j.appender.A1=org.apache.log4j.ConsoleAppender

log4j.appender.A1.layout=org.apache.log4j.PatternLayout

log4j.appender.A1.layout.ConversionPattern=[%c{1}][%p]: %m%n