how to consume spring beans from logback appender?

[sombriks]

Hello all,

currently i am looking for a a way to offer some sppring beans to a custom appender so i can, for example, log messages to a kafka topic using kafka template.

any guidance on how to perform that?

thanks in advance.

[ceki]

@sombriks I have created a Jira issue for tracking the topic of configuration extensions.

[ceki]

@sombriks The question is not specific enough to answer without meandering.

Anyway, appenders can take a custom parameter of any type as long as the parameter type has a default constructor. That should give you a lot of leeway already.

Another rather simple strategy is to chain configurators. You can configure a custom appender in your custom ch.qos.logback.core.spi.Configurator implementation and then delegate to the default configuration system by returning ExecutionStatus.INVOKE_NEXT_IF_ANY from your configure(Context) method.

[sombriks]

Hi @ceki thanks for put me in the right direction.
I'll see how spring-boot does that and see if, at some point, is possible to contribute the ApplicationContext itself to it.

[sombriks]

Another quick update, Appenders are loaded by a different classloader than the one loading the spring context, right?

i've tried a simple hack using static variables and they kep null, meaning the class i was seeing from spring bean wasn't the same the appender was seeing:

https://github.com/sombriks/sample-kafka/tree/main/service-producer-1/src/main/java/com/example/log2kafka

[ceki]

@sombriks It might be more of a initialization order issue rather than a class loader issue.

[sombriks]

i am setting the static attribute yet it remains null, i'll elaborate the test scenario later.

[maku]

Do you have a solution for this problem? I tried it but was not able to found one...

[maku]

It seems the problem with the class loading comes from the usage of spring-boot-devtools. When I remove this dependency I have no class loading issues anymore and I can the application context in a static variable