Unable to see MDC properties in App Insights via Function App

[mikeliucc]

Expected behavior

Based on the various docs on Microsoft Learn, I'm under the understanding that MDC properties can be captured under customDimensions in the traces table. However, so far I am only able to capture log messages (in message field). Can't find the MDC properties anywhere... Please help!

Actual behavior

No MDC properties are captured (AFAIK)

To Reproduce

We are using Java 8 to create our Function Apps. Here's our stack:

• Java 8 (no spring or springboot)
• SLF4J/Logback
• Cognitive Search SDK
• Cosmos SDK

Sample Application

In our function app, the code looks something like this:

Logger logger = LogFactory.getLogger(getClass()); ... MDC.put("search.result", ...); MDC.put("client.group", ...); ... loggger.info("Client requesting product search {} with {} ...", searchParam, clientContext);

System information

Please provide the following information:

• SDK Version: azure-core 1.35.0, azure-functions-java-library 3.0.0
• I've followed the instructions in
  • https://learn.microsoft.com/en-us/azure/azure-monitor/app/azure-web-apps-java
  • https://learn.microsoft.com/en-us/azure/azure-monitor/app/java-in-process-agent Log messages are captured as expected, but not the MDC properties.

Hoping for any suggestions you might have... Thanks in advance!

Logs

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Screenshots

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[mikeliucc]

Tagging @trask ... hoping you can provide some insights here (puns intended). Thanks!

[trask]

hi @mikeliucc! what does the sdkVersion column report on those trace records?

[trask]

we just released a new Public Preview of Application Insights Java agent integration into Azure Functions, can you try this (instead of attaching the Java agent yourself)?

I tested MDC yesterday using this route and it worked for me: https://github.com/trask/azure-functions-logback-mdc-example

[mikeliucc]

Hot cakes - That worked beautifully!!

Thank you so much!