Logback project
description
Transcript of Logback project
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Logback project
Ceki Gülcü & Sébastien Pennec
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No revolution, only evolution. log4j is no longer being actively
developed The same basic plumbing only
done better. Faster, smaller, higher gas
mileage, and generally more bang for the buck.
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Modular architecture logback-core
Joran, Status, Context, pattern parsing logback-classic
developer logging logback-access
container (access) logging
id Components
logback-core
logback-classic logback-access
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Access Logging
Definition: Access logThe log generated when a user
accesses a web-page on a web server.
Logback-access integrates seamlessly with Jetty and Tomcat
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logback-classic implements SLF4J
Logback offers a native implementation of the SLF4J API => Logback exposes its logging API through SLF4J.
If you are using logback, you are actually using SLF4J
SLF4J can delegate to log4j, logback, java.util.logging or JCL
SLF4J can bridge log4j, JCL and j.u.l.
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Joran: a bowl of fresh air
Given rules (patterns & actions) it can configure any object.
Joran can learn new rules on the fly. With its implicit rules, you don’t even
have to write rules. It can do partial replay. It is generic (can be used in your own
projects)
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Configuration example:
<appender name="FILE" class="ch.qos.logback.core.rolling.RollingFileAppender"> <File>logFile.log</File> <rollingPolicy
class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy"> <FileNamePattern> logFile.%d{yyyy-MM-dd}.log.zip </FileNamePatter> </rollingPolicy>
<layout class="ch.qos.logback.classic.PatternLayout"> <Pattern> %d{HH:mm:ss,SSS} [%thread] %-5level %logger{22} - %msg%n </Pattern> </layout></appender>
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Logback-access configuration<appender name="FILE" class="c.q.l.c.r.RollingFileAppender"> <File>access.log"</File> <rollingPolicy class="c.q.l.c.r.TimeBasedRollingPolicy"> <FileNamePattern> access.%d{yyyy-MM-dd}.log.zip </FileNamePattern> </rollingPolicy>
<layout class="c.q.l.access.PatternLayout"> <Pattern">combined</Pattern"> </layout></appender>
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Another example:<testShell name="test1"> <period>5 minutes</period> <!-- we need to configure a totally new test object for each run of the test --> <test class="com.wombat.myTest"> <DataSource class="c.w.JNDIDS"> <url>jndi://com.wombat/ds"</url> </DataSource> </test><testShell>
<testShell name="test2"> <period>60 seconds</period> <test class="com.wombat.myTest2"> <file>c:/wombat/foo.properties</file> </test></testShell>
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Is Joran for me?
Joran is ideal for building frameworks which need to support arbitrary user-developed plug-ins.
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Internal error reporting
Who shall guard the guards?
Logback modules cannot use logging to report their own state.
Something more generic is needed.
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Errors in action
Internal state available via StatusManager
Exceptions and status messages accompanied by references, i.e. URLs, to external documents
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JMX
Logback configuration can be reloaded via JMX
Statistical results exposed via JMX
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Documentation Major area of effort.
Complete manual, with over 150 pages of documentation, is available for free
A short introduction to access logging with logback-access and Jetty
javadoc, FAQ, error codes,…
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Filters, Filters. Filters everywhere
Filters attachable to any Appender Evaluator filters Janino filters for evaluation based on java
expressions TurboFilters for optimized global processing
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EvaluatorFilter & Janino<appender name="CYCLIC" class="c.q.l.core.read.CyclicBufferAppender"> <filter class="c.q.l.core.filter.EvaluatorFilter"> <evaluator name="loggingTaskEval">
<expression> logger.contains("LoggingTask") &&
message.contains("Howdydy-diddly-ho") && (timeStamp-loggerContext.getBirthTime()) >= 20000
</expression> </evaluator> <OnMatch>DENY</OnMatch>
</filter> <MaxSize>512</MaxSize></appender>
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TurboFilters<turboFilter class="c.q.l.classic.turbo.MDCFilter"> <MDCKey>userid</MDCKey> <Value>sebastien</Value> <OnMatch>ACCEPT</OnMatch></turboFilter>
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Parameterized loggingInteger entry = new Interger(50); logger.debug("The entry is "+entry+".");
can be optimized as: if(logger.isDebugEnabled()) { logger.debug("The entry is "+entry+".");}
or better yet:logger.debug("The entry is {}.", entry);
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Markers for specialized handling
Markers are metadata for logging statements, coloring them for specialized processing
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SiftingAppender or the appender-making appender Sift logging according to runtime attributes E.g. separate logs according to user
sessions, so that the log file generated by every user go into distinct log files, one log file per user.
Works with any appender, not just FileAppender
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SiftingAppender (continued) <appender name="SIFT"
class="ch.qos.logback.classic.sift.SiftingAppender"> <discriminator> <Key>userid</Key> <DefaultValue>unknown</DefaultValue> </discriminator> <sift> <appender name="FILE-${userid}" class="ch.qos.logback.core.FileAppender"> <File>${userid}.log</File>s <Append>false</Append> <layout> <Pattern>%d %level %mdc %logger - %msg%n</Pattern> </layout> </appender> </sift> </appender>
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Tested & Ready
Battery of over 450 unit tests
Tests written concomitantly with the code
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Package versions in stack traces
java.lang.NullPointerException at com.xyz.Wombat(Wombat.java:57) ~[wombat-1.3.jar:1.3] at com.xyz.Wombat(Wombat.java:76) ~[wombat-1.3.jar:1.3] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native) ~[na:1.5.0_06] at java.lang.reflect.Method.invoke(Method.java:585) ~[na:1.5.0_06] at junit.runners.TestMethod.invoke(TestMethod.java:59) [junit-4.4.jar:na] etc..
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logger name abbreviation
Conversion specifier
Displayed logger name
%logger mainPackage.sub.sample.Bar
%logger{15} m.s.sample.Bar
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Odds and ends RollingFileAppender automatic file compression the
background FileAppender and RollingFileAppender allow for the
same log file to be written to by instances located in different JVMs
10 fold improvement in the speed of transporting logging events over the wire
SMTPAppender now does TLS and SSL, subject line in outgoing email now based on PatternLayout
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Odds and ends II %() in pattern strings can do magic %-50(%d %level [%thread]) - %m%n DuplicateMessage filter
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Odds and ends II %() in pattern strings can do magic %-50(%d %level [%thread]) - %m%n DuplicateMessage filter
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Plans for the near future Finer threading model leading to less
contention Better documentation Eclipse plug-in to visualize your logs
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Conclusion
Logback is the unofficial successor of log4j, as the latter is no longer being actively developed.
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Questions?
read the docs at http://logback.qos.ch/ study the code at http://svn.qos.ch write to us at [email protected] file a bug report at http://jira.qos.ch/ chat with us at irc.freenode.net#qos talk to us at +41 21 312 32 26