Azure API Management
An Azure service that provides a hybrid, multi-cloud management platform for APIs.
2,312 questions
How to obtain the request size in APIM integrated with AOAI.
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koozo
0
Reputation points
#Problem
RequestSize cannot be obtained in APIM and is 0 bytes, which means that the "quota" policy and alerts in metrics cannot be executed as expected.
#What I want to solve
I want to set the RquestSize.
#Background
When using AOAI, I decided to go through APIM.
The reason for using APIM is that you can use subscription keys and policies.
In the policy, I want to limit the usage fee for one day.
This needs to be set for each subscription.
As far as I could tell, it could not be set by the usage fee.
Next, I found that there were policies for "azure-openai-token-limit" and "quota".
"azure-openai-token-limit" limits by token. That's fine, but it's in 1-minute units, so it didn't meet my requirements.
"Quota" limits by data volume. I thought it would be fine. However, as I continued to verify, I found that it was only working with ResponseSize. This means it can't be used.
But is that really the case? I checked Application Insights. I noticed that the RequestSize was not set in the ApiManagementGatewayLogs. The image shows the value of "Custom Measurements" when the Request was displayed in "Search for Transactions".
Perhaps the problem is not with the "quota" policy, but with the RequestSize being 0 bytes?
Response Size: 1748
Request Size: 0
I also started it from POSTMAN, and have pasted the size from there for reference.
So, what should I do to set the RequestSize correctly?
I look forward to any advice on how to solve this. Please help me.
As additional information, the AOAI log "AzureDiagnostics" output the body size for both the Request and Response as shown below. So there is no problem with AOAI, and I have determined that it is a problem on the APIM side.
requestLength: 498
responseLength: 1018
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Loknathsatyasaivarma Mahali 630 Reputation points Microsoft Vendor2025-02-25T05:24:28.2266667+00:00 Hello koozo,
Welcome to the Microsoft Q&A Platform! Thank you for asking your question here.
The issue with the RequestSize being logged as 0 bytes in APIM is likely preventing the quota policy from functioning as expected. First, verify that the request body is being properly passed through APIM without being altered by any policies. Add custom logging in the inbound policy to capture the request size and ensure it is correctly logged in APIM’s metrics. Ensure proper integration with Application Insights to correlate request and response sizes, and consider using other metrics like response size or token limits if necessary. Additionally, check for any APIM caching or buffering mechanisms that could affect the request size logging. Once the RequestSize is properly logged, the quota policy should work as expected.
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koozo 0 Reputation points
2025-02-25T10:34:06.7866667+00:00 Thank you for your response.
I confirmed in the Application Insights logs that the request body is properly passed to APIM without being modified by the policy.
I was also able to add custom logging.
I am outputting it in Trace. Please refer to the image.
Well, this didn't change the behavior of the Quota policy in any particular way.
It would be nice if I could overwrite the original RequestSize, but that hasn't been possible.
I'm currently stuck at this point, but how should I go about progressing further?
If you have any reference links or code, please let me know.
Also, are these steps generally necessary in APIM when using AOAI?
I would appreciate your response.
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Loknathsatyasaivarma Mahali 630 Reputation points Microsoft Vendor
2025-02-28T01:58:38.0566667+00:00 Hello koozo,
Sorry for the delay in response and thanks for provide the information please follow the below mention steps and please let us know the outcome.
- First check the APIM Gateway logs to ensure that the RequestSize is being captured accurately. If the RequestSize is consistently showing as 0 bytes, there may be an issue with how the RequestSize is being calculated or logged.
- Then if the RequestSize is not being captured correctly in the default logs, you may need to implement custom logging in APIM to track the RequestSize accurately. This can involve using policies like <log-to-eventhub> or <log-to-storage>, where you can include the RequestSize as a custom measurement.
- Once you have verified that the RequestSize is being logged correctly, you can then configure the Quota policy in APIM to limit the usage based on the RequestSize. You can set the quota limits based on the RequestSize value captured in the logs.
If you encounter any further issues or need more specific guidance on configuring the Quota policy with RequestSize in APIM, please feel free to provide additional details for further assistance.
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