How to use the "trace" Policy Statement for an Azure API service operation?

The "trace" policy statement allows you to generate debugging messages into the API trace output. The "trace" statement can be used in any policy blocks in the policy XML document.

The "trace" statement has the following syntax:

<trace source="MyDebug"/>  
    <!-- string expression or text -->  
</trace>

For example, the following inbound policy uses a "trace" statement to generate message using a text to the API trace output identified as "MyDebug":

<inbound>
    <trace source="MyDebug"/>I am here!</trace>
</inbound>

The following inbound policy uses a "trace" statement to generate message using a C# string expression to the API trace output identified as "MyDebug":

<inbound>
    <trace source="MyDebug"/> @("I am here!")</trace>
</inbound>

When you test the API operation with this policy on Azure developer portal, you will see a "MyDebug" section in the "trace" output tab displaying the given message.

For more information on "trace" policy statement, see API Management policies Website.

⇒ '@(...)' Expressions in Azure API Policy

⇐ Top Level Policy for All Azure APIs

⇑ Using Azure API Policy

⇑⇑ Microsoft Azure API Management Tutorials