GraalVM native image compatibility

[donbeave]

Hello!

Thank you for such an amazing library, I'm using it for some Micronaut projects.

I found that this library is not supporting the GraalVM native image feature, I have tried to build an application with logback-appender-nodep and it failed with an exception:

Error: Detected a direct/mapped ByteBuffer in the image heap. A direct ByteBuffer has a pointer to unmanaged C memory, and C memory from the image generator is not available at image runtime.A mapped ByteBuffer references a file descriptor, which is no longer open and mapped at run time.   To see how this object got instantiated use --trace-object-instantiation=java.nio.DirectByteBuffer. The object was probably created by a class initializer and is reachable from a static field. You can request class initialization at image runtime by using the option --initialize-at-run-time=<class-name>. Or you can write your own initialization methods and call them explicitly from your main entry point.
[application:38538]    Detailed message:
  [total]:  96,274.29 ms, Trace: Object was reached by
 7.97 GB
        reading field pl.tkowalcz.tjahzi.org.agrona.concurrent.UnsafeBuffer.byteBuffer of
                constant pl.tkowalcz.tjahzi.org.agrona.concurrent.UnsafeBuffer@f8a283 reached by
        reading field pl.tkowalcz.tjahzi.LogBufferSerializer.buffer of
                constant pl.tkowalcz.tjahzi.LogBufferSerializer@6740bb47 reached by
        reading field pl.tkowalcz.tjahzi.TjahziLogger.serializer of
                constant pl.tkowalcz.tjahzi.TjahziLogger@4da08d11 reached by
        reading field pl.tkowalcz.tjahzi.logback.LokiAppender.logger of
                constant pl.tkowalcz.tjahzi.logback.LokiAppender@1c61966b reached by
        indexing into array
                constant java.lang.Object[]@2da676b6 reached by
        reading field java.util.concurrent.CopyOnWriteArrayList.array of
                constant java.util.concurrent.CopyOnWriteArrayList@7516bfd8 reached by
        reading field ch.qos.logback.core.util.COWArrayList.underlyingList of
                constant ch.qos.logback.core.util.COWArrayList@4aa193f reached by
        reading field ch.qos.logback.core.spi.AppenderAttachableImpl.appenderList of
                constant ch.qos.logback.core.spi.AppenderAttachableImpl@7a6d3c78 reached by
        reading field ch.qos.logback.classic.Logger.aai of
                constant ch.qos.logback.classic.Logger@3a065022 reached by
        reading field ch.qos.logback.classic.LoggerContext.root of
                constant ch.qos.logback.classic.LoggerContext@61d7f698 reached by
        reading field ch.qos.logback.classic.Logger.loggerContext of
                constant ch.qos.logback.classic.Logger@658579fb reached by
        scanning method io.micronaut.runtime.Micronaut.lambda$null$0(Micronaut.java:111)
Call path from entry point to io.micronaut.runtime.Micronaut.lambda$null$0(EmbeddedApplication, CountDownLatch, boolean, Thread):
        at io.micronaut.runtime.Micronaut.lambda$null$0(Micronaut.java:111)
        at io.micronaut.runtime.Micronaut$$Lambda$1044/0x00000007c26c8b08.run(Unknown Source)
        at java.lang.Thread.run(Thread.java:833)
        at com.oracle.svm.core.thread.JavaThreads.threadStartRoutine(JavaThreads.java:596)
        at com.oracle.svm.core.posix.thread.PosixJavaThreads.pthreadStartRoutine(PosixJavaThreads.java:192)
        at com.oracle.svm.core.code.IsolateEnterStub.PosixJavaThreads_pthreadStartRoutine_e1f4a8c0039f8337338252cd8734f63a79b5e3df(generated:0)

Do you have any plans to add support for GraalVM?

If you need, I can provide a sample app to reproduce this error.

[tkowalcz]

Hi,

glad you find it useful! I will happily make changes to make the native image happy. I tried to create a project that builds native image and encountered several errors but not that one yet.

In principle it is complaining about log buffer component that has a buffer object that was allocated off heap. There is the configuration option UseOffHeapBuffer that you can set to false, maybe that will fix it?

[tkowalcz]

That being said - I will appreciate if you can send me that sample app so I can confirm it helps or develop a real fix.