How to call/retrieve value from Azure app config through APIM policy

Question

Hi Team, need help, I want to make call from APIM policy(c# code) to Azure app config to retrieve value against a key. But I am unable to figure out how to achieve this. Can you please help me. Thanks in advance

Answer 1

Amit Srivastava Thank you for posting your question in Microsoft Q&A.

Here are the steps you can follow to achieve this:

1. Enable System-assigned Managed Identity for your APIM instance as described Use managed identities in Azure API Management.
2. Assign Azure App Configuration Data Reader role for the managed identity as per doc: AD Authentication
3. Then write a custom policy to send request to Azure App Configuration Rest API (https://learn.microsoft.com/en-us/azure/azure-app-configuration/rest-api-key-value#get-key-value) to get the key value and use authentication-managed-identity policy to generate authorization token. Refer sample code snippet below: (replace <app-config-name> and testkeyname with actual value)

   <send-request mode="new" timeout="20" ignore-error="false" response-variable-name="tokenstate">
               <set-url>@("https://<app-config-name>.azconfig.io/kv/testkeyname?api-version=1.0")</set-url>
               <set-method>GET</set-method>
               <authentication-managed-identity resource="https://azconfig.io" ignore-error="false" />
           </send-request>
           <set-variable name="keyValue" value="@(((IResponse)context.Variables["tokenstate"]).Body.As<JObject>()["value"])" />

Note, the above code snippet is a sample policy for your reference, and you can customize it based on your need. If you face any issues, let me know. I hope this helps with your question.

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