Using Named Values in Policy XML files

Dev S 26

Azure Portal seems to return an error when using a named-value as part (not as whole) of an attribute value. However, using the Azure APIM VS Code extension doesn't have any trouble publishing the policy.xml for an API which has such a setting and the API is also working as expected.

Is this expected behavior by Azure Portal?

For example using

   <set-backend-service id="apim-generated-policy" backend-id="ECHO_{{Backend-ENV-ID}}" />

in policy.xml for an API through VS Code works, but, Azure Portal returns an error when browsing through the same API after an update. The error shown is

   API Management.  
   Could not load policies. Please try again later.

MuthuKumaranMurugaachari-MSFT 22,261 Reputation points

2022-10-28T14:46:30.947+00:00
@Dev S Thank you for reaching out to Microsoft Q&A. I tested the below policy snippet along with named values and backend-id as shown and worked as expected.

<set-backend-service id="apim-generated-policy" backend-id="ECHO_{{Backend-ENV-ID}}" />

Named value:

Backends:

Result:

I would like to capture additional details specific to your policy, named values etc. and will reach out to you separately.
MuthuKumaranMurugaachari-MSFT 22,261 Reputation points

2022-10-28T23:01:59.187+00:00

@Dev S Thank you for sharing the additional details. We found this is a bug in the portal and our product team is investigating the issue. Will keep you posted on the updates.
Dev S 26 Reputation points

2024-02-29T21:25:09.01+00:00
Has this problem been resolved? We are facing a problem again when editing the API Operation policy through the Azure Portal Editor. Now it complains that Expressions should be preceded with an @ sign. However, for Named Values, the documentation does not specify that we need to provide an @ before {{}}. For example

<set-backend-service id="apim-generated-policy" backend-id="ECHO_{{Backend-ENV-ID}}" />

is not the same as

<set-backend-service id="apim-generated-policy" backend-id="ECHO_@{{Backend-ENV-ID}}" />

where Backend-ENV-ID is a named value. However, the Portal editor complains when we don't have an @. We are able to update the policy successfully using Set-AzApiManagementPolicy without the @ before {{Backend-ENV-ID}}
Rodrigo Liberoff Vázquez 111 Reputation points MVP

2024-06-17T13:04:03.7633333+00:00
This issue is also happening with the latest version of the Azure API Management and the new backend pool policies.

So for instance, the following policy produces the error:

<policies> <inbound> <base /> <set-backend-service backend-id="openai-backends-pool" /> </inbound> <backend> <base /> </backend> <outbound> <base /> </outbound> <on-error> <base /> </on-error> </policies>

The backend pool is created as described here: https://video2.skills-academy.com/en-us/azure/api-management/backends?tabs=arm#load-balancing-options

Please help!

1 answer

Dev S 26 Reputation points

2024-02-29T21:42:28.2966667+00:00
Not sure if my previous comment was posted successfully, so reposting here: I think we might still have a problem with the editor on Azure Portal. Now when using Named Values in a Policy, the online Editor complains that we need to include an @ before an Expression. However, for Named Values used in a policy, the documentation does not specify this and it makes sense. For example:

<set-backend-service id="apim-generated-policy" backend-id="ECHO_{{Backend-ENV-ID}}" />

(above is NOT accepted in the Azure Portal Editor)

is not the same as

<set-backend-service id="apim-generated-policy" backend-id="ECHO_@{{Backend-ENV-ID}}" />

(above is accepted in the Azure Portal Editor)

We are able to successfully use Set-AzApiManagementPolicy to upload a policy without the @ before {{}} when specifying a Named Value.
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Using Named Values in Policy XML files

1 answer