How to get the value of Azure App Configuration Feature Flag with specific label from Spring boot?

Question

I started using Azure App Configuration service and Feature Flags functionality in my project. I followed this documentation and was able to create a Spring boot project. I also created a FeatureFlagService class and autowired the FeatureManager class in it as shown below :

@Service
public class FeatureFlagService {

  private FeatureManager featureManager;

  public FeatureFlagService(FeatureManager featureManager) {
     this.featureManager = featureManager;
  }

  public boolean isFeatureEnabled() {
     return featureManager.isEnabledAsync("scopeid/MyFeature").block();
  }

}

With this I get the value of the feature flag 'MyFeature' but with no label. I have the same feature defined with different labels in Azure App Configuration as shown below.

I need to fetch the feature flag with specific label. How can I achieve it at runtime? I don't see a way to do it using the FeatureManager class.

Answer 1

They only way to load from a label is by using spring.cloud.azure.appconfiguration.stores[0].feature-flags.label-filter, the Feature Management Library itself has no concept of a label.

Answer 2

I got FeatureManager to pull in non-blank labels with the following configuration path:

spring.cloud.azure.appconfiguration.stores[0].feature-flags.selects[0].label-filter

The key is that the other answer was missing the selects piece.

Here it is in yaml form:

spring:
  cloud:
    azure:
      appconfiguration:
        enabled: true
        stores[0]:
          connection-string: ${APP_CONFIGURATION_CONNECTION_STRING}
          feature-flags:
            enabled: true
            selects[0]:
              # this pulls in flags with "local" label and no label (trailing comma)
              label-filter: local,
              # you can put key-filter here, too

Relevant source code:

• com.azure.spring.cloud.appconfiguration.config.implementation.properties.FeatureFlagKeyValueSelector
• com.azure.spring.cloud.appconfiguration.config.implementation.AppConfigurationPropertySourceLocator#create

Artifact:

artifactId=spring-cloud-azure-appconfiguration-config
groupId=com.azure.spring
version=5.8.0

If you notice in the code, you can also use active Spring profiles for filtering the Azure feature flags by label.

You may want to to wire in a AppConfigurationRefresh bean to refresh feature flag values on demand. I think the refresh default is 5 minutes. You can setup a Spring scheduled task to invoke it more frequently. Or if you can find a way to override the default, feel free to share it here.