modify-feature-flags

name	modify-feature-flags
description	Feature flag patterns for the CheddarFlow project. TRIGGER when: writing or modifying feature flag code, FunWithFlags usage, CFXFeatureFlags calls, or conditional feature enablement. Also trigger when adding new flags to config or checking flag state. DO NOT TRIGGER when: working with code that doesn't involve feature flags.

Feature Flags

Managed via FunWithFlags with Ecto persistence, wrapped by cfx_feature_flags.

CFXFeatureFlags API

CFXFeatureFlags.enabled?(:my_flag)
CFXFeatureFlags.enable(:my_flag)
CFXFeatureFlags.disable(:my_flag)
CFXFeatureFlags.clear(:my_flag)
CFXFeatureFlags.all_flags()
CFXFeatureFlags.all_flag_names()

Default Flags

Configured per environment, initialized on startup via CFXFeatureFlags.initialize/1:

# config/config.exs (dev/test defaults)
config :cfx_feature_flags, :default_flags,
  symbol_price_polling: false,
  options_contract_polling: false,
  options_contract_expiry_scraping: false

# config/prod.exs
config :cfx_feature_flags, :default_flags,
  symbol_price_polling: true,
  options_contract_polling: false,
  options_contract_expiry_scraping: true

initialize/1 will not overwrite already-persisted flags — only sets defaults for new flags.

Persistence & Cache

• Persistence: FunWithFlags.Store.Persistent.Ecto backed by Schemas.Repo (prod only)
• Cache: In-process, 900s TTL in prod
• Cache busting: Via Phoenix.PubSub through CFXWeb.PubSub — propagates across cluster

Adding a New Feature Flag

1. Add flag name and default to :default_flags in config.exs and prod.exs
2. Check with CFXFeatureFlags.enabled?(:flag_name)
3. Auto-initialized on next deploy via CFXFeatureFlags.initialize/0
4. Toggle at runtime: CFXFeatureFlags.enable(:flag_name)