Cloudwatch logger appender doesn't work with native image

[andriy-dmytruk]

Issue description

Reproduce

• Create a micronaut application (micronaut launch link).
• Add the following dependency:

  implementation("io.micronaut.aws:micronaut-aws-cloudwatch-logging")
  

• Modify the src/main/resources/logback.xml to be the following:

  <configuration>
    <appender name='CLOUDWATCH' class='io.micronaut.aws.cloudwatch.logging.CloudWatchLoggingAppender'>
        <groupName>MyLogGroup</groupName>
        <streamName>MyStreamName</streamName>
        <createGroupAndStream>true</createGroupAndStream>
        <encoder class='ch.qos.logback.core.encoder.LayoutWrappingEncoder'>
            <layout class='ch.qos.logback.contrib.json.classic.JsonLayout'>
                <jsonFormatter class='io.micronaut.aws.cloudwatch.logging.CloudWatchJsonFormatter'/>
            </layout>
        </encoder>
    </appender>
  
    <root level='INFO'>
        <appender-ref ref='CLOUDWATCH'/>
    </root>
  </configuration>

• Run ./gradlew nativeRun

Error

With the configuration in build.gradle:

graalvmNative {
    binaries.configureEach {
        buildArgs.addAll(
                "--trace-object-instantiation=java.lang.Thread"
        )
    }
}

the following exception is thrown (important lines marked):

Error: Detected a started Thread in the image heap. Threads running in the image generator are no longer running at image runtime.  Object has been initialized by the io.micronaut.runtime.Micronaut class initializer with a trace: 
 	at java.lang.Thread.<init>(Thread.java:708)
	at java.util.concurrent.Executors$DefaultThreadFactory.newThread(Executors.java:660)
	at ch.qos.logback.core.util.ExecutorServiceUtil$1.newThread(ExecutorServiceUtil.java:42)
	at java.util.concurrent.ThreadPoolExecutor$Worker.<init>(ThreadPoolExecutor.java:630)
	at java.util.concurrent.ThreadPoolExecutor.addWorker(ThreadPoolExecutor.java:920)
	at java.util.concurrent.ThreadPoolExecutor.ensurePrestart(ThreadPoolExecutor.java:1593)
	at java.util.concurrent.ScheduledThreadPoolExecutor.delayedExecute(ScheduledThreadPoolExecutor.java:346)
	at java.util.concurrent.ScheduledThreadPoolExecutor.scheduleAtFixedRate(ScheduledThreadPoolExecutor.java:632)
-->  at io.micronaut.aws.cloudwatch.logging.CloudWatchLoggingAppender.start(CloudWatchLoggingAppender.java:161)
	at ch.qos.logback.core.joran.action.AppenderAction.end(AppenderAction.java:90)
	at ch.qos.logback.core.joran.spi.Interpreter.callEndAction(Interpreter.java:309)
	at ch.qos.logback.core.joran.spi.Interpreter.endElement(Interpreter.java:193)
	at ch.qos.logback.core.joran.spi.Interpreter.endElement(Interpreter.java:179)
	at ch.qos.logback.core.joran.spi.EventPlayer.play(EventPlayer.java:62)
	at ch.qos.logback.core.joran.GenericConfigurator.doConfigure(GenericConfigurator.java:165)
	at ch.qos.logback.core.joran.GenericConfigurator.doConfigure(GenericConfigurator.java:152)
	at ch.qos.logback.core.joran.GenericConfigurator.doConfigure(GenericConfigurator.java:110)
	at ch.qos.logback.core.joran.GenericConfigurator.doConfigure(GenericConfigurator.java:53)
	at ch.qos.logback.classic.util.ContextInitializer.configureByResource(ContextInitializer.java:64)
	at ch.qos.logback.classic.util.ContextInitializer.autoConfig(ContextInitializer.java:134)
	at org.slf4j.impl.StaticLoggerBinder.init(StaticLoggerBinder.java:84)
	at org.slf4j.impl.StaticLoggerBinder.<clinit>(StaticLoggerBinder.java:55)
	at org.slf4j.LoggerFactory.bind(LoggerFactory.java:150)
	at org.slf4j.LoggerFactory.performInitialization(LoggerFactory.java:124)
	at org.slf4j.LoggerFactory.getILoggerFactory(LoggerFactory.java:417)
	at org.slf4j.LoggerFactory.getLogger(LoggerFactory.java:362)
	at org.slf4j.LoggerFactory.getLogger(LoggerFactory.java:388)
-->  at io.micronaut.runtime.Micronaut.<clinit>(Micronaut.java:53)

The issue is caused because native image doesn't support thread creation during build time and the the appended calls scheduleAtFixedRate in the CloudWatchLoggingAppender. The appender needs to be started during build time in this case as loggers are required by Micronaut, ApplicationContext and other core classes, and the logger starts all the appenders on creation.