Feature Flag Management System in Go

Feature flags (also known as feature toggles) are a powerful technique for enabling or disabling features in your application without deploying new code. This challenge asks you to implement a basic feature flag management system in Go, allowing you to dynamically control feature availability based on a configuration. This is useful for A/B testing, gradual rollouts, and emergency feature disabling.

Problem Description

You need to create a FeatureFlagManager struct in Go that can manage feature flags. The manager should be able to:

1. Load Flags: Load feature flag configurations from a simple map. The map keys are feature flag names (strings), and the values are booleans representing whether the feature is enabled (true) or disabled (false).
2. Check Flag Status: Provide a method IsEnabled(flagName string) bool that returns true if the specified feature flag is enabled, and false otherwise. If a flag is not found in the configuration, it should be treated as disabled.
3. Update Flag Status: Provide a method SetFlag(flagName string, enabled bool) that updates the status of a feature flag. If the flag doesn't exist, it should be created.
4. Handle Missing Flags Gracefully: The IsEnabled method should return false if a requested flag is not present in the configuration.

Examples

Example 1:

Input:
  - Feature flag configuration: map[string]bool{"new_ui": true, "dark_mode": false}
  - Call: FeatureFlagManager.IsEnabled("new_ui")
Output: true
Explanation: The "new_ui" flag is enabled in the configuration.

Example 2:

Input:
  - Feature flag configuration: map[string]bool{"new_ui": true, "dark_mode": false}
  - Call: FeatureFlagManager.IsEnabled("dark_mode")
Output: false
Explanation: The "dark_mode" flag is disabled in the configuration.

Example 3:

Input:
  - Feature flag configuration: map[string]bool{"new_ui": true, "dark_mode": false}
  - Call: FeatureFlagManager.IsEnabled("experimental_feature")
Output: false
Explanation: The "experimental_feature" flag is not present in the configuration, so it's treated as disabled.

Example 4:

Input:
  - Feature flag configuration: map[string]bool{"new_ui": true, "dark_mode": false}
  - Call: FeatureFlagManager.SetFlag("dark_mode", true)
  - Call: FeatureFlagManager.IsEnabled("dark_mode")
Output: true
Explanation: The "dark_mode" flag is updated to enabled.

Constraints

• The feature flag names will be strings.
• The feature flag values will be booleans.
• The number of feature flags will be relatively small (less than 100). Performance is not a primary concern for this exercise.
• The input configuration map will always be valid (no nil maps).

Notes

• Consider using a map[string]bool to store the feature flag configurations.
• Think about how to handle the case where a flag is not found in the configuration.
• The SetFlag method should modify the internal state of the FeatureFlagManager.
• Focus on clarity and correctness over extreme optimization. A simple, readable solution is preferred.
• You do not need to persist the flags to disk. The configuration should live in memory.