`SentryAppender` causing warnings

[chandrabol]

Description

We have an application that defines custom Log Levels.

When we use the JsonTemplateLayout (https://logging.apache.org/log4j/2.x/manual/json-template-layout.html)
we sometimes get a Null pointer Exception

Configuration

Version: 2.19.0

Operating system: MacOs

JDK: JDK 17

Logs

2024-09-19 11:15:12,451 Log4j2-TF-2-AsyncLoggerConfig-2 ERROR An exception occurred processing Appender Console java.lang.NullPointerException: seq
	at java.base/java.util.Objects.requireNonNull(Objects.java:235)
	at org.apache.logging.log4j.layout.template.json.util.JsonWriter.writeRawString(JsonWriter.java:800)
	at org.apache.logging.log4j.layout.template.json.resolver.LevelResolver.lambda$createNameResolver$3(LevelResolver.java:144)
	at org.apache.logging.log4j.layout.template.json.resolver.LevelResolver.resolve(LevelResolver.java:172)
	at org.apache.logging.log4j.layout.template.json.resolver.LevelResolver.resolve(LevelResolver.java:75)
	at org.apache.logging.log4j.layout.template.json.resolver.TemplateResolver.resolve(TemplateResolver.java:66)
	at org.apache.logging.log4j.layout.template.json.resolver.TemplateResolvers$PrefixedFieldResolverMethod.resolve(TemplateResolvers.java:353)
	at org.apache.logging.log4j.layout.template.json.resolver.TemplateResolvers$MapResolver.resolve(TemplateResolvers.java:409)
	at org.apache.logging.log4j.layout.template.json.JsonTemplateLayout.encode(JsonTemplateLayout.java:302)
	at org.apache.logging.log4j.layout.template.json.JsonTemplateLayout.encode(JsonTemplateLayout.java:58)
	at org.apache.logging.log4j.core.appender.AbstractOutputStreamAppender.directEncodeEvent(AbstractOutputStreamAppender.java:215)
	at org.apache.logging.log4j.core.appender.AbstractOutputStreamAppender.tryAppend(AbstractOutputStreamAppender.java:208)
	at org.apache.logging.log4j.core.appender.AbstractOutputStreamAppender.append(AbstractOutputStreamAppender.java:199)
	at org.apache.logging.log4j.core.config.AppenderControl.tryCallAppender(AppenderControl.java:161)
	at org.apache.logging.log4j.core.config.AppenderControl.callAppender0(AppenderControl.java:134)
	at org.apache.logging.log4j.core.config.AppenderControl.callAppenderPreventRecursion(AppenderControl.java:125)
	at org.apache.logging.log4j.core.config.AppenderControl.callAppender(AppenderControl.java:89)
	at org.apache.logging.log4j.core.config.LoggerConfig.callAppenders(LoggerConfig.java:683)
	at org.apache.logging.log4j.core.async.AsyncLoggerConfig.callAppenders(AsyncLoggerConfig.java:149)
	at org.apache.logging.log4j.core.config.LoggerConfig.processLogEvent(LoggerConfig.java:641)
	at org.apache.logging.log4j.core.config.LoggerConfig.log(LoggerConfig.java:624)
	at org.apache.logging.log4j.core.async.AsyncLoggerConfig.log(AsyncLoggerConfig.java:143)
	at org.apache.logging.log4j.core.async.AsyncLoggerConfig.logToAsyncLoggerConfigsOnCurrentThread(AsyncLoggerConfig.java:191)
	at org.apache.logging.log4j.core.async.AsyncLoggerConfigDisruptor$Log4jEventWrapperHandler.onEvent(AsyncLoggerConfigDisruptor.java:112)
	at org.apache.logging.log4j.core.async.AsyncLoggerConfigDisruptor$Log4jEventWrapperHandler.onEvent(AsyncLoggerConfigDisruptor.java:98)
	at com.lmax.disruptor.BatchEventProcessor.processEvents(BatchEventProcessor.java:168)
	at com.lmax.disruptor.BatchEventProcessor.run(BatchEventProcessor.java:125)
	at java.base/java.lang.Thread.run(Thread.java:840)

Reproduction

public static void main(String args[]) {
log.log(EngineLogLevel.AUDIT.getLevel(), Utilities.toJson(auditLog));
}

[vy]

This is a duplicate of #1805, which was fixed in 2.21.0. Would you mind using the most recent Log4j version, i.e., 2.23.0, please?

[chandrabol]

@vy After I update the version to 2.23.0,

1. Custom log level is printed.
2. Getting the below exception for the log4j2 plugin.

2024-09-19T07:12:03.632479Z main WARN Could not examine class org/apache/logging/log4j/core/async/JCToolsBlockingQueueFactory$MpscBlockingQueue.class java.lang.NoClassDefFoundError: org/jctools/queues/MpscArrayQueue at java.base/java.lang.ClassLoader.defineClass1(Native Method) at java.base/java.lang.ClassLoader.defineClass(ClassLoader.java:1017) at java.base/java.security.SecureClassLoader.defineClass(SecureClassLoader.java:150) at java.base/jdk.internal.loader.BuiltinClassLoader.defineClass(BuiltinClassLoader.java:862) at java.base/jdk.internal.loader.BuiltinClassLoader.findClassOnClassPathOrNull(BuiltinClassLoader.java:760) at java.base/jdk.internal.loader.BuiltinClassLoader.loadClassOrNull(BuiltinClassLoader.java:681) at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:639) at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:188) at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:525) at org.apache.logging.log4j.core.config.plugins.util.ResolverUtil.addIfMatching(ResolverUtil.java:462) at org.apache.logging.log4j.core.config.plugins.util.ResolverUtil.loadImplementationsInJar(ResolverUtil.java:357) at org.apache.logging.log4j.core.config.plugins.util.ResolverUtil.findInPackage(ResolverUtil.java:236) at org.apache.logging.log4j.core.config.plugins.util.PluginRegistry.loadFromPackage(PluginRegistry.java:224) at org.apache.logging.log4j.core.config.plugins.util.PluginManager.collectPlugins(PluginManager.java:162) at org.apache.logging.log4j.core.config.AbstractConfiguration.initialize(AbstractConfiguration.java:242) at org.apache.logging.log4j.core.config.AbstractConfiguration.start(AbstractConfiguration.java:313) at org.apache.logging.log4j.core.LoggerContext.setConfiguration(LoggerContext.java:631) at org.apache.logging.log4j.core.LoggerContext.reconfigure(LoggerContext.java:713) at org.apache.logging.log4j.core.LoggerContext.reconfigure(LoggerContext.java:735) at org.apache.logging.log4j.core.LoggerContext.start(LoggerContext.java:260) at org.apache.logging.log4j.core.impl.Log4jContextFactory.getContext(Log4jContextFactory.java:154) at org.apache.logging.log4j.core.impl.Log4jContextFactory.getContext(Log4jContextFactory.java:46) at org.apache.logging.log4j.LogManager.getContext(LogManager.java:197) at org.apache.logging.log4j.LogManager.getLogger(LogManager.java:611) Caused by: java.lang.ClassNotFoundException: org.jctools.queues.MpscArrayQueue at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:641) at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:188) at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:525) ... 25 more

[vy]

@chandrabol, typo. 🤦 Mind upgrading to 2.24.0, please? If your problem persists, could you share your pom.xml and log4j2.xml, please?

Edit: You can workaround the issue by adding org.jctools:jctools-core to your dependencies. But, AFAICT, that should not have been needed while upgrading from 2.19.0 to 2.24.0.

[chandrabol]

Upgraded to 2.24.0.

Getting this message -

2024-09-19T07:28:20.687326Z main WARN The use of package scanning to locate Log4j plugins is deprecated.
Please remove the `packages` attribute from your configuration file.
See https://logging.apache.org/log4j/2.x/faq.html#package-scanning for details.
2024-09-19T07:28:20.687549Z main WARN Some custom `Core` Log4j plugins are not properly registered:
	io.sentry.log4j2.SentryAppender
Please consider reporting this to the maintainers of these plugins.
See https://logging.apache.org/log4j/2.x/manual/plugins.html#plugin-registry for details.

Pom.xml - <log4j2.version>2.24.0</log4j2.version>

Log4j2.xml -

<?xml version="1.0" encoding="UTF-8"?>
<configuration status="warn" packages="org.apache.logging.log4j.core,io.sentry.log4j2">
    <Properties>
        <Property name="instant">false</Property>
        <Property name="LOG_LEVEL">INFO</Property>
        <Property name="XRAY_LOG_LEVEL">WARN</Property>
        <Property name="AUDIT_LOG_LEVEL">TRACE</Property>
    </Properties>
    <appenders>
        <Console name="Console" target="SYSTEM_OUT">
            <JsonTemplateLayout eventTemplateUri="classpath:logStructure.json" locationInfoEnabled="true"/>
        </Console>
        <Console name="Audit" target="SYSTEM_OUT">
            <PatternLayout pattern='%m%n'/>
        </Console>
        <Sentry name="Sentry" />
    </appenders>

    <Loggers>
        <AsyncLogger name="com.gravty.framework.audit" additivity="false" level="TRACE" includeLocation="true">
            <AppenderRef ref="Audit" level = "${env:AUDIT_LOG_LEVEL}"/>
        </AsyncLogger>
        <AsyncLogger name="com.gravty" additivity="false" level="DEBUG" includeLocation="true">
            <appender-ref ref="Console" level = "${env:LOG_LEVEL}"/>
            <appender-ref ref="Sentry" level="ERROR" />
        </AsyncLogger>
        <AsyncLogger name="com.amazonaws.xray" additivity="false" level="WARN" includeLocation="true">
            <appender-ref ref="Console" level = "${env:XRAY_LOG_LEVEL}"/>
        </AsyncLogger>
        <AsyncRoot level="WARN" additivity="false" includeLocation="true">
            <appender-ref ref="Console"/>
        </AsyncRoot>
    </Loggers>
</configuration>

[vy]

@chandrabol, could you share the complete pom.xml and log4j2.xml, please? If they happen to contain lines you don't want to disclose, could you trim these files down so that we can reproduce the issue on our side, please?

[ppkarwasz]

@chandrabol,

Can you check if removing the packages attribute from your configuration file removes both warnings. Removing the packages attribute should not remove this warning:

2024-09-19T07:28:20.687549Z main WARN Some custom `Core` Log4j plugins are not properly registered:
	io.sentry.log4j2.SentryAppender
Please consider reporting this to the maintainers of these plugins.
See https://logging.apache.org/log4j/2.x/manual/plugins.html#plugin-registry for details.

If it disappears and everything works, it might be a false positive.

Which version of io.sentry:sentry-log4j2 are you using? Version 7.14.0 properly registers a Log4j plugins.

Are you using shading? See our Shading/Shadowing FAQ entry.