V1ncentzzZ commented on a change in pull request #14304:
URL: https://github.com/apache/flink/pull/14304#discussion_r538300524
##########
File path: docs/deployment/advanced/logging.md
##########
@@ -59,49 +71,47 @@ For Flink distributions this means you have to
## Configuring logback
-For users and developers alike it is important to control the logging
framework.
-The configuration of the logging framework is exclusively done by
configuration files.
-The configuration file either has to be specified by setting the environment
property `-Dlogback.configurationFile=<file>` or by putting `logback.xml` in
the classpath.
-The `conf` directory contains a `logback.xml` file which can be modified and
is used if Flink is started outside of an IDE and with the provided starting
scripts.
-The provided `logback.xml` has the following form:
-
-{% highlight xml %}
-<configuration>
- <appender name="file" class="ch.qos.logback.core.FileAppender">
- <file>${log.file}</file>
- <append>false</append>
- <encoder>
- <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{60}
%X{sourceThread} - %msg%n</pattern>
- </encoder>
- </appender>
-
- <root level="INFO">
- <appender-ref ref="file"/>
- </root>
-</configuration>
-{% endhighlight %}
+To use Flink with [logback](https://logback.qos.ch/) you must ensure that:
+- `org.apache.logging.log4j:log4j-slf4j-impl` is not on the classpath,
+- `ch.qos.logback:logback-core` and `ch.qos.logback:logback-classic` are on
the classpath.
-In order to control the logging level of
`org.apache.flink.runtime.jobgraph.JobGraph`, for example, one would have to
add the following line to the configuration file.
+In the IDE this means you have to replace such dependencies defined in your
pom, and possibly add exclusions on dependencies that transitively depend on
them.
-{% highlight xml %}
-<logger name="org.apache.flink.runtime.jobgraph.JobGraph" level="DEBUG"/>
-{% endhighlight %}
+For Flink distributions this means you have to
+- remove the `log4j-slf4j-impl` jar from the `lib` directory,
+- add the `logback-core`, and `logback-classic` jars to the `lib` directory.
+
+The Flink distribution ships with the following logback configuration files in
the `conf` directory, which are used automatically if logback is enabled:
+- `logback-session.properties`: used by the command line interface when
starting a Kubernetes/Yarn session cluster (i.e.,
`kubernetes-session.sh`/`yarn-session.sh`)
+- `logback-console.properties`: used for Job-/TaskManagers if they are run in
the foreground (e.g., Kubernetes)
+- `logback.xml`: used for command line interface and Job-/TaskManagers by
default
-For further information on configuring logback see [LOGback's
manual](http://logback.qos.ch/manual/configuration.html).
+<div class="alert alert-info" markdown="span">
+ <strong>Note:</strong> Logback 1.3+ requires SLF4J 2, which is currently not
supported.
+</div>
## Best practices for developers
-The loggers using slf4j are created by calling
+You can create an SLF4J logger by calling
`org.slf4j.LoggerFactory#LoggerFactory.getLogger` with the `Class` of your
class as an argument.
+
+We highly recommend storing this logger in a `private static final` field.
{% highlight java %}
import org.slf4j.LoggerFactory
import org.slf4j.Logger
Review comment:
I think we can add a semicolon at the end and it's the best to change
the import order according to checkstyle.
----------------------------------------------------------------
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
For queries about this service, please contact Infrastructure at:
[email protected]
