Examine App Configuration feature management

Completed

Feature management constitutes contemporary software development practices decoupling feature releases from code deployments enabling on-demand feature availability modifications.

Feature flags receive comprehensive coverage in dedicated modules, while Azure App Configuration Service capabilities warrant notation as centralized feature flag storage and management solutions. Alternative nomenclature includes feature toggles and feature switches.

Basic concepts

Feature management terminology encompasses:

• Feature flag: Binary state variables (on or off) with associated code blocks. Flag state determines code block execution behavior.
• Feature manager: Application package managing feature flag lifecycles across applications. Functionality includes feature flag caching and state update operations.
• Filter: Evaluation rules determining feature flag states. Filter representations include user groups, device types, browser types, geographic locations, and temporal windows.

Effective feature management implementation requires coordinated component collaboration:

• Applications consuming feature flags.
• Separate repositories storing feature flags with current state metadata.

Component interaction patterns receive illustration through subsequent examples.

Feature flag usage in code

Application-level feature flag implementation follows straightforward patterns. Feature flags function as Boolean state variables employed within if conditional statements:

if (featureFlag) {
    // Run the following code.
}

featureFlag set to True executes enclosed code blocks; alternative conditions skip execution. Static value assignment demonstrates fundamental implementation:

bool featureFlag = true;

Rule-based flag state evaluation enables dynamic behavior:

bool featureFlag = isBetaUser();

Enhanced feature flag patterns incorporate else statements for comprehensive conditional logic:

if (featureFlag) {
    // This following code will run if the featureFlag value is true.
} else {
    // This following code will run if the featureFlag value is false.
}

Feature flag declaration

Feature flag composition includes names and filter lists evaluating feature state (on when values equal True).

Filters define use cases determining feature enablement conditions.

Multiple filter configurations employ traversal operations until filter criteria determine feature enablement.

Feature flag on states trigger remaining filter result omission. Filter evaluation failures result in feature flag off states.

Feature managers support appsettings.json configuration sources for feature flag declarations.

JSON file feature flag configuration example:

"FeatureManagement": {
    "FeatureA": true, // Feature flag set to on
    "FeatureB": false, // Feature flag set to off
    "FeatureC": {
        "EnabledFor": [
            {
                "Name": "Percentage",
                "Parameters": {
                    "Value": 50
                }
            }
        ]
    }
}

Feature flag repository

Effective feature flag utilization requires application-level feature flag externalization.

Externalization enables feature flag state modifications without application modification or redeployment operations.

Azure App Configuration provides centralized repository architecture for feature flag management.

Feature flag definition, state manipulation capabilities enable rapid, confident operational adjustments.

App Configuration libraries across programming language frameworks facilitate application-level feature flag access operations.