Hi, Is there any solution for this issue? I got error when retrieving AKV secret using parameter ."message": "ErrorCode=InvalidTemplate, ErrorMessage=The template function 'linkedService' is not defined or not valid." Here are the steps to reproduce the issue I created AKV linked service, using parameter like below I created a rest api linked service, and try to retrieve a secret by using the AKV above , and append it to Auth headers, like below click test connection, I got error "message": "ErrorCode=InvalidTemplate, ErrorMessage=The template function 'linkedService' is not defined or not valid." And I could see, I have another linked service, it is retrieving AKV secret like below. it works perfect, but got error only for the rest API, where I would need to retrieve it in Auth headers

Hi @Smaran Thoomu I really appreciated your help! Just because the answer you shared me before was not matching my issue, so I pressed "No". And I have resolved my issue. I found somewhat the issue was because that we could not set AKV URL directly. I have to set AKV URL as parameter in REST API, Click the AKV like below in Auth Header And set the AKV URL as @string(linkedService().AKVURL), like below, and it would work perfectly!

Error when retrieving AKV secret in ADF rest API linked service

Carrie 50

Hi,

Is there any solution for this issue?

I got error when retrieving AKV secret using parameter

."message": "ErrorCode=InvalidTemplate, ErrorMessage=The template function 'linkedService' is not defined or not valid."

Here are the steps to reproduce the issue

I created AKV linked service, using parameter like below
I created a rest api linked service, and try to retrieve a secret by using the AKV above , and append it to Auth headers, like below
click test connection, I got error "message": "ErrorCode=InvalidTemplate, ErrorMessage=The template function 'linkedService' is not defined or not valid."

And I could see, I have another linked service, it is retrieving AKV secret like below. it works perfect, but got error only for the rest API, where I would need to retrieve it in Auth headers

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Smaran Thoomu 20,305 Reputation points Microsoft Vendor

2025-02-10T12:16:02.23+00:00
Hi @Zhenqi Liu
Welcome to Microsoft Q&A platform and thanks for posting your query here.
Based on the error you’re encountering happens because the linkedService() function is not supported for use in headers or directly within the REST API linked service configuration in Azure Data Factory (ADF). This limitation is why you’re seeing the error:

ErrorCode=InvalidTemplate, ErrorMessage=The template function 'linkedService' is not defined or not valid.

Here’s how you can resolve the issue step by step:

Why This Happens

The linkedService() function is specifically meant for referencing linked services within a pipeline or activity, not directly inside configurations like headers in a REST API linked service. So, when you try to use it in that context, it results in an invalid template error.

Steps to Fix the Issue

Extract the Secret in a Pipeline First: Instead of trying to directly fetch the Key Vault secret in the REST API linked service, retrieve it first in the pipeline. You can do this using either: Lookup activity: Use this to fetch the secret. Web activity: Configure this to call the Key Vault REST API and retrieve the secret. Once retrieved, store the secret in a pipeline variable.

Pass the Secret to the REST API Linked Service: Use the variable containing the secret in the Authorization header or wherever it’s required. For example: In the header, reference the variable like: @pipeline().parameters.secretValue

Update the REST API Linked Service: Instead of attempting to reference the Key Vault secret directly in the REST API linked service, add a parameter in the linked service for the secret value (e.g., authToken). Pass this parameter from the pipeline when invoking the REST API.

Double-Check Key Vault Permissions: Ensure the system-managed identity (or whatever identity is used) has Get permission for the secret in Azure Key Vault.

The best approach is to retrieve the secret in the pipeline first and then use it in the REST API activity. This method aligns with ADF's limitations and ensures your configuration works smoothly.

I hope this helps! Let me know if you have any further questions.
Carrie 50 Reputation points

2025-02-11T06:16:46.8233333+00:00
Hi @Smaran Thoomu

Thank you!

The background is that I have to set parameters for linked services so as I could deploy the same ADF pipelines to different environments just changing the linked service parameters, because the only difference of each environment are host/endpoint of the linked services.

So the solution you shared above, might be not easy for me. Is it possible to enable this function in future?

Since we have hundreds of pipelines, which are using the same linked service, if we have to do it like the way you shared, I have to do the same setting for all of these pipelines, which seems not efficient.

For AzureKeyVault linked service that is not using parameter case, we could set Auth header using Azure key vault value, why not be able to set Auth header when AzureKeyVault linked service is using parameter?

I could see there are same request, like this Q&A

Is there any other workaround instead of fixing hundreds of existing pipelines to set the duplicate settings?

Thank you!
Smaran Thoomu 20,305 Reputation points Microsoft Vendor

2025-02-11T18:03:22.3766667+00:00
Hi @Carrie
Thanks for your feedback, and I truly appreciate you sharing your concerns. I noticed that you rated my previous response with low satisfaction, and I want to make sure we address your issue in the best way possible. If there’s anything specific that didn’t fully meet your expectations, please let me know, I’d be happy to explore alternative solutions with you.

Regarding your question, I completely understand that updating hundreds of pipelines isn’t practical. Unfortunately, ADF doesn’t currently support using linkedService() inside REST API linked service headers when parameters are involved. However, here are a couple of potential workarounds that might help:

Use a parameter inside the linked service – Instead of trying to retrieve the secret directly in the REST API linked service, you can define a parameter (e.g., authToken) and pass the correct secret dynamically at deployment. This way, you only need to update the linked service, not every pipeline.

Automate deployment with ARM templates or CI/CD – If your environment setup supports ARM templates or DevOps pipelines, you can store and apply the correct secrets automatically based on the environment, avoiding manual updates.

I know this isn’t a perfect solution, but right now, ADF doesn’t support using Key Vault secrets directly in REST API linked service headers when parameters are involved. Hopefully, Microsoft will introduce this in the future, I would recommend sharing your feedback on the Azure Feedback Portal, as they do consider user suggestions for future updates.

Let me know if this helps, or if you’d like to explore any other options. I’ll do my best to find a workaround that works for you!

If this answers your query, do click Accept Answer and Yes for was this answer helpful. And, if you have any further query do let us know.
Smaran Thoomu 20,305 Reputation points Microsoft Vendor

2025-02-12T10:51:52.0233333+00:00

@Carrie Following up to see if the below answer was helpful. If this answers your query, do click Accept Answer and Yes for was this answer helpful. And, if you have any further query do let us know.

Accepted answer

Smaran Thoomu 20,305 Reputation points Microsoft Vendor

2025-02-12T15:59:39.3166667+00:00
Hi @Carrie
I'm glad that you were able to resolve your issue and thank you for posting your solution so that others experiencing the same thing can easily reference this! Since the Microsoft Q&A community has a policy that "The question author cannot accept their own answer. They can only accept answers by others "I'll repost your solution in case you'd like to accept the answer.

Ask: Is there any solution for this issue?

I got error when retrieving AKV secret using parameter

."message": "ErrorCode=InvalidTemplate, ErrorMessage=The template function 'linkedService' is not defined or not valid."

Here are the steps to reproduce the issue

I created AKV linked service, using parameter like below

I created a rest api linked service, and try to retrieve a secret by using the AKV above , and append it to Auth headers, like below

click test connection, I got error "message": "ErrorCode=InvalidTemplate, ErrorMessage=The template function 'linkedService' is not defined or not valid."

And I could see, I have another linked service, it is retrieving AKV secret like below. it works perfect, but got error only for the rest API, where I would need to retrieve it in Auth headers

Solution: I found somewhat the issue was because that we could not set AKV URL directly.

I have to

set AKV URL as parameter in REST API,

Click the AKV like below in Auth Header

And set the AKV URL as @string(linkedService().AKVURL), like below, and it would work perfectly!

If I missed anything please let me know and I'd be happy to add it to my answer, or feel free to comment below with any additional information.

If you have any other questions, please let me know. Thank you again for your time and patience throughout this issue.

Please don’t forget to Accept Answer and Yes for "was this answer helpful" wherever the information provided helps you, this can be beneficial to other community members.
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Carrie 50 Reputation points

2025-02-12T13:31:52.6966667+00:00
Hi @Smaran Thoomu

I really appreciated your help! Just because the answer you shared me before was not matching my issue, so I pressed "No".

And I have resolved my issue.

I found somewhat the issue was because that we could not set AKV URL directly.

I have to

set AKV URL as parameter in REST API,

Click the AKV like below in Auth Header

And set the AKV URL as @string(linkedService().AKVURL), like below, and it would work perfectly!
Please sign in to rate this answer.
Smaran Thoomu 20,305 Reputation points Microsoft Vendor

2025-02-12T16:00:07.6+00:00

@Carrie Glad to know your issue has been resolved. Since the Microsoft Q&A community has a policy that "The question author cannot accept their own answer. They can only accept answers by others "I'll repost your solution in case you'd like to accept the answer.
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