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GradleUp / shadow

Gradle plugin to create fat/uber JARs, apply file transforms, and relocate packages for applications and libraries. Gradle version of Maven's Shade plugin.
https://www.gradleup.com/shadow/
Apache License 2.0
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Shadowing logback packages to hide it from spring-boot #529

Open xbaldxo opened 5 years ago

xbaldxo commented 5 years ago

Hi, I have self-written library which I use as javaagent and it has to have logback dependency. When I run this library as javaagent it must not conflict with target application's logback classes. I tried to relocate logback and plugin did it.

relocate 'ch.qos.logback.classic','shadow.ch.qos.logback.classic'

Everything related to ch.qos.logback.classic now is under 'shadow' directory. But when I run agent with spring boot executable jar I have error like:

Caused by: java.lang.IllegalArgumentException: LoggerFactory is not a Logback LoggerContext but Logback is on the classpath. Either remove Logback or the competing implementation (class shadow.ch.qos.logback.classic.LoggerContext loaded from file:/my-java-agent.jar).

This happens because agent loaded first but when spring boot starts loading it's ClassLoader recognise somehow that my shadow.ch.qos.logback.classic is logback implementation and it is already loaded.

What I need it to hide my logback dependency and use it only if target application does not have it's own.

Can you advice something please?

johnrengelman commented 4 years ago

I'm pretty sure this is related to how slf4j detects implementations on the classpath. There's nothing I can do here. It has nothing to do with shadow or package relocating.