labels: mergeable

Fixes: #issue

Motivation and Context

Accessing the underlying configuration values is complex (it relies on several IConfigurationStore instances) and as a result, requires a couple of one-off orphan functions and oddly located helper methods to interact with the configuration objects. All of this implementation detail leaks into the EppoClient

Description

new interface:

export interface IConfiguration {
  getFlag(key: FlagKey | HashedFlagKey): Flag | ObfuscatedFlag | null;
  getFlags(): Record<FlagKey | HashedFlagKey, Flag | ObfuscatedFlag>;
  getBandits(): Record<BanditKey, BanditParameters>;
  getBanditVariations(): Record<FlagKey | HashedFlagKey, BanditVariation[]>;
  getFlagBanditVariations(flagKey: FlagKey | HashedFlagKey): BanditVariation[];
  getFlagVariationBandit(flagKey: FlagKey | HashedFlagKey, variationValue: string): BanditParameters | null;
  getBandit(key: BanditKey): BanditParameters | null;
  getFlagConfigDetails(): ConfigDetails;
  getFlagKeys(): FlagKey[] | HashedFlagKey[];
  isObfuscated(): boolean;
  isInitialized(): boolean;
}

An instance of this interface is available from the ConfigurationRequestor (a default instance is created if the config requestor has not been instantiated yet).

Each call into the EppoClient that requires config access first gets the current IConfiguration then uses that config object throughout the callstack.

For now, the IConfiguration instance is backed by the various config stores, so all this PR does is move access from the stores directly to corresponding methods on the IConfiguration instance.

How has this been tested?

• Tests for the new classes and methods
• existing tests continue to function unchanged with the refactoring

What's left to do

Because the config is backed by the stores which are written to by the ConfigRequestor, the configuration can actually change during a call-in computation. As such, the next step in this process will be to introduce a ReadOnlyConfiguration that will be a snapshot of the config instead of a life object.