Appender OutOf Memory Error for MuleSoft Apps

[KHALIFA-SH]

Discussed in #120

^{Originally posted by KHALIFA-SH December 16, 2023}
I have Used the log4j2 appender in MuleSoft project and I'm getting an outOfMemory Error when sending logs to Loki.
Attached the stack trace...
When I upgrade the worker size to at least 0.2 V core I don't see this error. I just want to ask if there is something I can do to avoid this error with minimal worker size (.01 v core).

Thank you!

Error Stack

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

• Initializing app 'grafana-loki-test' +
  ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
  ERROR StatusConsoleListener Could not create plugin of type class pl.tkowalcz.tjahzi.log4j2.LokiAppender for element Loki: java.lang.OutOfMemoryError: Direct buffer memory
  java.lang.OutOfMemoryError: Direct buffer memory
  at java.nio.Bits.reserveMemory(Bits.java:695)
  at java.nio.DirectByteBuffer.(DirectByteBuffer.java:123)
  at java.nio.ByteBuffer.allocateDirect(ByteBuffer.java:311)
  at pl.tkowalcz.tjahzi.TjahziInitializer.allocateJavaBuffer(TjahziInitializer.java:101)
  at pl.tkowalcz.tjahzi.TjahziInitializer.createLoggingSystem(TjahziInitializer.java:32)
  at pl.tkowalcz.tjahzi.log4j2.LokiAppenderBuilder.build(LokiAppenderBuilder.java:152)
  at pl.tkowalcz.tjahzi.log4j2.LokiAppenderBuilder.build(LokiAppenderBuilder.java:30)
  ....
  ERROR StatusConsoleListener Unable to invoke factory method in class pl.tkowalcz.tjahzi.log4j2.LokiAppender for element Loki: java.lang.IllegalStateException: No factory method found for class pl.tkowalcz.tjahzi.log4j2.LokiAppender
  java.lang.IllegalStateException: No factory method found for class pl.tkowalcz.tjahzi.log4j2.LokiAppender
  at org.apache.logging.log4j.core.config.plugins.util.PluginBuilder.findFactoryMethod(PluginBuilder.java:260)
  at org.apache.logging.log4j.core.config.plugins.util.PluginBuilder.build(PluginBuilder.java:136)
  at org.apache.logging.log4j.core.config.AbstractConfiguration.createPluginObject(AbstractConfiguration.java:1138)
  at org.apache.logging.log4j.core.config.AbstractConfiguration.createConfiguration(AbstractConfiguration.java:1063)
  ....

[kshkur]

Fixed with "bufferSizeMegabytes" allocation

[tkowalcz]

Hi. Sorry for a late answer. The JVM has a user-settable upper limit on the maximum amount of allocatable direct buffer memory. It can be controlled by -XX:MaxDirectMemorySize=<size> option to java invocation. The stack trace indicates that you hit that limit.

The solution is to set smaller buffer like @kshkur suggests or set useOffHeapBuffer to false in Tjahzi configuration so that the buffer will be allocated on java heap.