Application with Sentry logger fails to remove ThreadLocal when app is stopped on Tomcat

[wojciechmusial]

I'm using Tomcat 8 and lastest version of Sentry SDK:

<dependency>
      <groupId>io.sentry</groupId>
      <artifactId>sentry-log4j2</artifactId>
      <version>1.1.0</version>
</dependency>

I configured my logging in files:

log4j2.properties

appender.console.type=Console
appender.console.name=STDOUT
appender.console.layout.type=PatternLayout
appender.console.layout.pattern=%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n

appender.sentry.type=Sentry
appender.sentry.name=Sentry

rootLogger.level=WARN
rootLogger.appenderRef.stdout.ref=STDOUT
rootLogger.appenderRef.sentry.ref=Sentry
rootLogger.appenderRef.sentry.level=WARN

sentry.properties

dsn=<my_sentry_dsn>
async.gracefulshutdown=false

I assumed that using async.gracefulshutdown=false will kill all running threads properly, so that my application is not exposed to any memory leak problems. When I redeploy my application Tomcat is reporting that ThreadLocal connected to Sentry failed to be removed:

19-Jun-2017 22:06:57.423 SEVERE [localhost-startStop-2] org.apache.catalina.loader.WebappClassLoaderBase.checkThreadLocalMapForLeaks The web application [ROOT] created a ThreadLocal with key of type [io.sentry.context.ThreadLocalContextManager$1] (value [io.sentry.context.ThreadLocalContextManager$1@5d7c6e1d]) and a value of type [io.sentry.context.Context] (value [io.sentry.context.Context@40c92b58]) but failed to remove it when the web application was stopped. Threads are going to be renewed over time to try and avoid a probable memory leak.

Is there something that could be done in reference to above issue?

[bretthoerner]

Thanks for the report, I'll check this out ASAP. I haven't done a lot of testing with full blown application servers, I think this should hopefully be a quick fix tomorrow.

[bretthoerner]

Merged something that should fix this, releasing soon.

[wukrwurk]

I got a similar issue with Tomcat 9 and sentry 5.3.7