Application Insights logging with log4j in java

Question

I recently discovered that there was log4j extension for application insights . So following the example online I attempted to configure application insights and log4j to log items from my servlets living in an azure hosted tomcat.

Well, the example seems very incomplete as it never makes mention of the key at all. From looking through the source I see an example (test?) that uses <param> within the log4j.xml but not much explanation of how to use or debug the actual logger.

Does anyone out there have any pointers on how to actually use/implement the ApplicationInsightsAppender for log4j?

Here's the source on github https://github.com/Microsoft/ApplicationInsights-Java

Answer 1

You don't have to configure the instrumentation key for the appender, it will be done automatically if you properly configured the AI SDK.

As mentioned in the first section of the log4j extension for application insights article, is it assumed that you already configured Application Insights for Java and more specifically configured the instrumentation key using the AI configuration file .

Once you've done this, the instrumentation key will be taken from the configuration file.

The appenders indeed have hidden API for setting the instrumentation key, though not documented.