Environment Configuration

Responsibility

internal/config/config.go loads all backend runtime configuration from environment variables with sensible defaults. The client (examples/client) reads its own subset directly. No config files are used (12-factor).

Backend variables

Var	Default	Meaning
PORT	8080	Listen port
LOG_LEVEL	info	debug/info/warn/error
STORE	postgres	postgres or memory
DATABASE_URL	(empty)	Postgres connection string (required when STORE=postgres)
SHUTDOWN_TIMEOUT	10s	Graceful shutdown budget
READ_TIMEOUT	15s	HTTP read timeout
WRITE_TIMEOUT	15s	HTTP write timeout

Validation: PORT must be non-empty; STORE must be postgres or memory. DATABASE_URL is required only in postgres mode.

Client variables

Var	Default	Meaning
CONTROL_PLANE_URL	http://localhost:8080	Backend base URL
POLL_INTERVAL	2s	Poll cadence
USER_KEY	demo-user	User key for rollout hashing
FLAG_NAME	(empty)	Optional single-flag filter

Flow

config.Load() is called once in runServer() (cmd/flaggo/main.go). The resulting Config drives store selection, logger level, server timeouts, and router wiring. The frontend (cmd/flaggo-web) uses BACKEND_URL.

Degraded mode

If STORE=postgres but DATABASE_URL is empty or connection/migration fails, the backend logs the error, sets readiness false, and starts without flag routes. /healthz stays ok; /readyz returns 503.

Local template

.env.example documents the variables; copy to .env for local dev (gitignored).

Related

• openwiki/runtime/lifecycle.md
• openwiki/architecture/overview.md