Merge pull request #275506 from dlepow/trunc

[APIM] Log entry limit

Author: denrea

articles/api-management/api-management-howto-use-azure-monitor.md

@@ -7,7 +7,7 @@ author: dlepow
 ms.service: api-management
 ms.custom: engagement-fy23, devdivchpfy22
 ms.topic: tutorial
-ms.date: 06/27/2023
+ms.date: 05/15/2024
 ms.author: danlep
 ---
 # Tutorial: Monitor published APIs
@@ -179,7 +179,7 @@ For more information about using resource logs for API Management, see:
 
 ## Modify API logging settings
 
-By default, when you create a diagnostic setting to enable collection of resource logs, logging is enabled for all APIs, with default settings. You can adjust the logging settings for all APIs, or override them for individual APIs. For example, adjust the sampling rate or the verbosity of the data, or disable logging for some APIs.
+By default, when you create a diagnostic setting to enable collection of resource logs, logging is enabled for all APIs, with default settings. You can adjust the logging settings for all APIs, or override them for individual APIs. For example, adjust the sampling rate or the verbosity of the data, enable logging of headers or request or response payloads, or disable logging for some APIs.
 
 For details about the logging settings, see [Diagnostic logging settings reference](diagnostic-logs-reference.md).
 
@@ -188,14 +188,16 @@ To configure logging settings for all APIs:
 1. In the left menu of your API Management instance, select **APIs** > **All APIs**.
 1. Select the **Settings** tab from the top bar.
 1. Scroll down to the **Diagnostic Logs** section, and select the **Azure Monitor** tab.
-1. Review the settings and make changes if needed. Select **Save**.
+1. Review the settings and make changes if needed. Select **Save**. 
 
 To configure logging settings for a specific API:
 
 1. In the left menu of your API Management instance, select **APIs** and then the name of the API.
 1. Select the **Settings** tab from the top bar.
 1. Scroll down to the **Diagnostic Logs** section, and select the **Azure Monitor** tab.
-1. Review the settings and make changes if needed. Select **Save**.
+1. Review the settings and make changes if needed. Select **Save**. 
+
+[!INCLUDE [api-management-log-entry-size-limit](../../includes/api-management-log-entry-size-limit.md)]
 
 ## Next steps
 

articles/api-management/diagnostic-logs-reference.md

@@ -6,7 +6,7 @@ author: dlepow
 
 ms.service: api-management
 ms.topic: reference
-ms.date: 11/18/2022
+ms.date: 05/15/2024
 ms.author: danlep
 ms.custom: engagement-fy23
 ---
@@ -35,11 +35,13 @@ This reference describes settings for API diagnostics logging from an API Manage
 | Verbosity         |                                   | Specifies the verbosity of the logs and whether custom traces that are configured in [trace](trace-policy.md) policies are logged.    <br/><br/>* Error - failed requests, and custom traces of severity `error`<br/>* Information -  failed and successful requests, and custom traces of severity `error` and `information`<br/> * Verbose - failed and successful requests, and custom traces of severity `error`, `information`, and `verbose`<br/><br/>Default: Information  | 
 | Correlation protocol |  |  Specifies the protocol used to correlate telemetry sent by multiple components to Application Insights. Default: Legacy <br/><br/>For information, see [Telemetry correlation in Application Insights](../azure-monitor/app/distributed-tracing-telemetry-correlation.md).  |
 | Headers to log              | list                              | Specifies the headers that are logged for requests and responses.  Default: no headers are logged.                                                                                                                                                                                                             |
-| Number of payload bytes to log | integer                           | Specifies the number of initial bytes of the body that are logged for requests and responses. Maximum: 8,192. Default: 0                                                                                                                                                                                                   |
+| Number of payload (body) bytes to log| integer                           | Specifies the number of initial bytes of the frontend or backend request or response body that are logged. Maximum: 8,192. Default: 0                                                                                                                                                                                                |
 | Frontend Request  |                                   | Specifies whether and how *frontend requests* (requests incoming to the API Management gateway) are logged.<br/><br/> If this setting is enabled, specify **Headers to log**, **Number of payload bytes to log**, or both.                                                                                                                                                                        |
 | Frontend Response |                                   | Specifies whether and how *frontend responses* (responses outgoing from the API Management gateway) are logged.<br/><br/> If this setting is enabled, specify **Headers to log**, **Number of payload bytes to log**, or both.                                                                                                                                                                   |
 | Backend Request   |                                   | Specifies whether and how *backend requests* (requests outgoing from the API Management gateway) are logged.<br/><br/> If this setting is enabled, specify **Headers to log**, **Number of payload bytes to log**, or both.                                                                                                                                                                        |
-| Backend Response  |                                   | Specifies whether and how *backend responses* (responses incoming to the API Management gateway) are logged. <br/><br/> If this setting is enabled, specify **Headers to log**, **Number of payload bytes to log**, or both.                                                     
+| Backend Response  |                                   | Specifies whether and how *backend responses* (responses incoming to the API Management gateway) are logged. <br/><br/> If this setting is enabled, specify **Headers to log**, **Number of payload bytes to log**, or both.     
+
+[!INCLUDE [api-management-log-entry-size-limit](../../includes/api-management-log-entry-size-limit.md)]                                                
 
 ## Next steps
 

includes/api-management-log-entry-size-limit.md

@@ -0,0 +1,10 @@
+---
+author: dlepow
+ms.service: api-management
+ms.topic: include
+ms.date: 05/15/2024
+ms.author: danlep
+---
+
+> [!IMPORTANT]
+> If enabled, logged request or response payloads can be up to 8,192 bytes. API Management also enforces a 32 KB limit for a diagnostic log entry sent to Azure Monitor, which includes the payloads and other attributes such as status codes, headers, and timestamps. If the combined size of the attributes exceeds 32 KB, API Management trims the entry by removing all body and trace content.