Setting DEBUG log level in python azure function

Question

Hi,

I am successfully loging messages from my Python Azure function (http trigger) to App Insights at the INFO level but my DEBUG logs are not showing.

The following doesn't solve the problem:

import logging

logging.basicConfig(level=logging.DEBUG)

@app.route(route="test", methods=['GET'])
def test(req: func.HttpRequest, context: func.Context) -> func.HttpResponse:
	logging.debug('Some message')
	...

I also tried to modify hosts.json to the following:

{
  "version": "2.0",
  "logging": {
    "logLevel": {
      "Function": "Debug"
    },
    "applicationInsights": {
      "samplingSettings": {
        "isEnabled": true,
        "excludedTypes": "Request"
      }
    }
  },
  "extensionBundle": {
    "id": "Microsoft.Azure.Functions.ExtensionBundle",
    "version": "[3.*, 4.0.0)"
  }
}

(per https://learn.microsoft.com/en-us/azure/azure-functions/configure-monitoring?tabs=v2#configure-log-levels)

Doesn't work either.

Thanks in advance for any suggestion.

Answer 1

@JDR Welcome to Microsoft Q&A Forum, Thank you for posting your query here!

I understand that you are having trouble logging DEBUG messages from their Python Azure function to App Insights. You have tried modifying the logging level and host.json file, but the DEBUG logs are still not showing.

I was able to create a simple Python HTTPTrigger function app and deployed it to Azure. I have the below lines of code added in my app:

    // Add the import statement
    import logging

    // Then you can add the below lines in your code. 
    logging.Logger.root.level = logging.DEBUG
    logger = logging.getLogger('MyHttpFunc')
    
    logger.setLevel(logging.DEBUG)
    logging.debug('This is a debug log.')

    logging.info('This is an info log')
    logging.info('Python HTTP Triggered function processed a request.')

I have the below within my host.json:

{
  "version": "2.0",
  "logging": {
    "logLevel": {
      "Host.Results": "Error",
      "Function": "Debug",
      "Host.Aggregator": "Trace"
    },
    "applicationInsights": {
      "samplingSettings": {
        "isEnabled": true,
        "excludedTypes": "Request"
      }
    }
  },
  "extensionBundle": {
    "id": "Microsoft.Azure.Functions.ExtensionBundle",
    "version": "[3.*, 4.0.0)"
  }
}

While the HTTP Trigger was invoked and executed, I could see the debug statements in the App Insights trace logs:

Also note that for a function app to send data to Application Insights, it needs to know the instrumentation key of an Application Insights resource. The key must be in an app setting named APPINSIGHTS_INSTRUMENTATIONKEY.

Hope this helps.

If you have any follow-up questions, please let me know. I would be happy to help.

**

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