How to configure Logback to add host-name/IP to each log event?

Question

I am using Logback for logging. Scribe appenders send the logs in real time to a central Scribe aggregator. But I don't know how to add source machine IP in the logs for each log events. Looking at the aggregated central Scribe logs, it is almost impossible to know which machine is sending the logs. Hence, appending the IP of source machine to each log event will be helpful, and will be really great if we can control that through logback configuration.

Answer 1

It's possible to pass down hostname to remote receiver thru contextName.
Add following to logback.xml on all appenders:

<contextName>${HOSTNAME}</contextName>

Then, on aggregator instance, it will be available for inclusion in the pattern:

<pattern>%contextName %d %-5level %logger{35} - %msg %n</pattern>

Answer 2

According to the Logback docs, there's now a CanonicalHostNamePropertyDefiner expressly to add a hostname to your logs. Add a define to your project:

<define name="hostname" class="ch.qos.logback.core.property.CanonicalHostNamePropertyDefiner"/>

and access it as ${hostname}