Azure App Configuration: Issues Overriding Non-Prefixed Keys with Prefixed Variants

Kyle Knapp 10

Given an Azure App Configuration key with no prefix: Setting123, I am not able to override this key with a prefixed version of it Environment:Setting123.

This returns the key with the value from the non-prefixed key. If I don't execute TrimKeyPrefix then I see both values in the built config:

config.AddAzureAppConfiguration(options =>{    
options.Connect(new Uri(url), token)        
.Select(KeyFilter.Any)    
.Select($"{environment}:*").TrimKeyPrefix($"{environment}:");
});

If I add a prefix to the non-prefixed key, then the last one added takes precedence as expected:

config.AddAzureAppConfiguration(options =>{    
options.Connect(new Uri(url), token)        
.Select($"{commonPrefix}*").TrimKeyPrefix($"{commonPrefix}")    
.Select($"{environment}:*").TrimKeyPrefix($"{environment}:");
});

I'm seeking clarification as to if this is intended. I wasn't able to find any documentation that stated explicitly either way, but would expect it to have been called out if you are unable to override a non-prefixed key with a prefixed one.

Perhaps there are best practices that I am unaware of, would appreciate any guidance or input.

MayankBargali-MSFT 70,421 Reputation points

2023-12-28T11:04:12.7166667+00:00

@Kyle Knapp Thanks for reaching out. Not an expert with the option configuration but reviewing and AFAIK it is possible to override a non-prefixed key with a prefixed one. However, it is important to note that the keys with the dev label will override the same keys with the default label. In your case, it seems that you are trying to override a non-prefixed key with a prefixed one. If you are not able to do so, it might be due to some other configuration issue. I would suggest checking the configuration settings and ensuring that the prefix is correctly specified. Additionally, you can try removing the TrimKeyPrefix method to see if it resolves the issue. If the issue persists, you can enable debug logs.

Not specially for your use case but sharing the document on the best practices for key value compositions and Use labels to provide per-environment configuration values.
Kyle Knapp 10 Reputation points

2023-12-28T11:52:40.67+00:00

this didn't post so I rewrote below
Kyle Knapp 10 Reputation points

2023-12-28T12:02:00.72+00:00

@MayankBargali-MSFT can you clarify "the keys with the dev label will override the same keys with the default label"? I am not using labels, only prefixes. With the prefix, I am wanting the environment specific key to override the prefix-less key's value.

The code works in every case except when the key to be overridden does not have a prefix. I obtain the correct key and value when selecting the prefix keys only, and when the non-prefixed keys are given a prefix.

I do observe that it appears a merge of some sort is taking place, as the non-prefixed key is alphabetically at the bottom of Providers.AzureAppConfigurationProvider.Data, however after the prefix has been trimmed its position remains where it was previously (alphabetized by the prefix) in the list.

Removing TrimKeyPrefix() simply allows both keys to exist, Environment:Setting123 and Setting123.
Kyle Knapp 10 Reputation points

2023-12-28T12:14:39.2766667+00:00
It seems that since KeyFilter.Any (or "*") is picking up both the prefixed and non-prefixed keys, that the second Select isn't actually loading anything new. When TrimKeyPrefix($"{environment}:") is executed, it is applied to all of the keys with no regard for the order in which they were loaded. Since the environment specific value isn't being added in the second Select, the order of adding them isn't honored because it isn't recognized.

Now I'm hoping there's a way to get the options to resolve before setting new options, I've tried this but the lambda is evaluated at once so I don't think there's a way to accomplish what I'm after:

.Select(KeyFilter.Any).TrimKeyPrefix($"{environment}:") .Select($"{environment}:*").TrimKeyPrefix($"{environment}:");

I've tried this as well to no avail:

options.Select(KeyFilter.Any).TrimKeyPrefix($"{environment}:"); options.Select($"{environment}:*").TrimKeyPrefix($"{environment}:");
MayankBargali-MSFT 70,421 Reputation points

2023-12-29T03:09:53.28+00:00

@Kyle Knapp I will check with my team and keep you posted.

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Azure App Configuration: Issues Overriding Non-Prefixed Keys with Prefixed Variants

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