config

Overview ¶

Package config provides an env-only configuration loader for paper-board services.

MustBind reads environment variables onto a service-defined struct via reflection over `env`, `default`, and `validate` struct tags. After binding, validator/v10 runs Struct() on the destination. Required fields with no env or default cause MustBind to log to stderr and exit non-zero.

Flags and config files are intentionally unsupported. Service binaries MAY accept positional/flag args via cobra for one-shot operations (e.g. migrator subcommands), but those flags MUST NOT override Config fields.

Example:

type Config struct {
    DatabaseURL string        `env:"DATABASE_URL" validate:"required,url"`
    ServerPort  int           `env:"SERVER_PORT" default:"8080" validate:"gte=1,lte=65535"`
    LogLevel    string        `env:"LOG_LEVEL" default:"info" validate:"oneof=debug info warn error"`
    Timeout     time.Duration `env:"TIMEOUT" default:"30s"`
    Tags        []string      `env:"TAGS" default:"a,b,c"`
    Debug       bool          `env:"DEBUG" default:"false"`
}

cfg := config.MustBind[Config]()