The ResponseBody is garbled in the ApiManagementGatewayLogs talbe

Question

We have deployed an API to call OpenAI API for the chat completion using API Management service and have enabled Azure Monitor to log the response body.
I have made a request using the Test function of the API and I have confirmed that the response body just looks fine.
But the response body in the column ResponseBody of ApiManagementGatewayLogs table is garbled.
https://learn.microsoft.com/en-us/azure/azure-monitor/reference/tables/ApiManagementGatewayLogs

The language of the response is in English so there should be no encoding issue.
The picture on the left side is the response in the Test function and the one on the right side is the content of ResponseBody of the ApiManagementGatewayLogs table.

Have checked the content using the SDK and it is also garbled.
Does anyone have similar issue and how did you solve it?
Thank you very much!

Answer 1

Hi ,

Thanks for reaching out to Microsoft Q&A.

The issue of garbled content in the ResponseBody of the ApiManagementGatewayLogs table often occurs due to the data being stored in a compressed or non-human-readable format for logging purposes. Here's how you can address this:

Possible Causes and Solutions

1. Data Compression in Logs:
   • The ResponseBody might be stored in a compressed or binary format by Azure API Management logs. You may need to decode or decompress the data to view it in a human-readable format.
   • Solution: Use a decoding library or method (e.g., Base64 decoding or decompression) to extract the readable content from the logs. Look at the API Management documentation or SDK for any specific decoding guidelines.
2. Log Configuration:
   • Check the configuration of Azure Monitor diagnostic settings for the API Management service. The ResponseBody might be partially logged or transformed due to policy or diagnostic configurations.
   • Solution: Ensure that the diagnostic settings are configured to capture the full ResponseBody. Verify the policy settings in your API Management instance to ensure they are not altering or compressing the response.
3. Encryption:
   • If the ResponseBody contains sensitive information, it might be encrypted before being stored in the logs.
   • Solution: Confirm whether encryption policies are applied and use the appropriate keys or methods to decrypt the log data.
4. Encoding Issues:
   • Although you've stated the response language is English, ensure there are no discrepancies in encoding between the API response and how the log table interprets it.
   • Solution: Validate the content encoding settings in both the API response and the API Management logging configuration. Ensure UTF-8 or a similar universal encoding is consistently used.
5. Using KQL to Extract Data:
   • If the data appears garbled when queried, use Azure Monitor's KQL (Kusto Query Language) to extract and transform the ResponseBody content.
   • Example KQL as below

     ApiManagementGatewayLogs | extend DecodedResponse = base64_decode_tostring(ResponseBody)

Possible Next Steps:

1. Check if the response is compressed or encoded and decode it using SDKs or KQL transformations.
2. Review the API Management diagnostic and logging policies for ResponseBody settings.
3. Test the response logging using a small payload to debug the issue in isolation.

If these steps do not resolve the issue, escalate with Azure Support for further investigation, as it might be an underlying platform issue.

Please feel free to click the 'Upvote' (Thumbs-up) button and 'Accept as Answer'. This helps the community by allowing others with similar queries to easily find the solution.