Reload log4j2 configuration on demand

Question

I have my log4j2.xml config file set to be checked every 30 seconds:

<Configuration status="WARN" monitorInterval="30">
    ...
</Configuration>

Is it possible to programmatically tell log4j2 to check for changes in the configuration instead of having a timeout?

N.B. I don't want to programmatically load the configuration specifying the config file, I just want to tell log4j2 to check the config file that has been loaded before as if the monitorInterval expired.

Thanks!

Karenkarena

See logging.apache.org/log4j/1.2/faq.html#a3.6 – Sleepyhead

@Sleepyhead I don't want to have log4j "watch" the config file... I just want to tell log4j when to check – Karenkarena

Please find my comment from another https://mcmap.net/q/534574/-how-to-reload-a-programmed-log4j2-configuration-in-java – Villous

Answer 1

It looks like I've found the solution:

((org.apache.logging.log4j.core.LoggerContext) LogManager.getContext(false)).reconfigure();

Does anyone see anything wrong/side-effects with this?

Karenkarena

Unfortunately, I found this problemmatic when there are multiple logging contexts, like in OSGI or in web apps. In this case the code above reloads config in only one of the contexts – Thorman

@Thorman what would the solution for OSGI/web-apps environment? – Stasiastasis

Sorry, @gaurav, already don't remember. Finally I preferred LogBack – Thorman

Answer 2

There is currently no clean way to do this. It can be done with reflection. (Of course this may break if the implementation changes.)

UPDATE: this is wrong. There is a clean way, see jamp's answer below.

org.apache.logging.log4j.core.LoggerContext ctx = (org.apache.logging.log4j.core.LoggerContext) LogManager.getContext(false);

org.apache.logging.log4j.core.config.FileConfigurationMonitor mon = (org.apache.logging.log4j.core.config.FileConfigurationMonitor) ctx.getConfiguration().getConfigurationMonitor();

// use reflection to get monitor's "nextCheck" field.
// set field accessible
// set field value to zero

mon.checkConfiguration();

Wholly

Oh. There is no API for doing what you want to do. I honestly believe reflection is your only option with log4j-2.1. You can of course raise a feature request on the Jira issue tracker. – Wholly

It looks like you're right... can't find anything... :( Much to my regret, I'll accept it ;) – Karenkarena

I take it back... I might have found a solution... I posted it as an answer – Karenkarena

Answer 3

What about using org.apache.logging.log4j.core.config.Configurator ?

   LoggerContext loggerContext = LoggerContext.getContext(false);
   final Configuration configuration = loggerContext.getConfiguration();
   Configurator.reconfigure(configuration);

Midshipman

just calling Configurator.reconfigure(); is work for me – Aliunde

Answer 4

What about org.apache.logging.log4j.core.config.Configurator.reconfigure()?

Broadleaf