Env Vars

All environment variables reside in pkg/config/features. They're categorised within their respective features such as database.go or service.go. Each env var must have a mapstructure: decoration that spells it in caps when parsing an ENV. You can add your own, it's as simple as adding a new line in any of these files, or create your own.

Below is a sample of pkg/config/features/service.go:

type ServiceConfig struct {
	Host                   string `mapstructure:"HOST"`
	ProtectedApiPort       string `mapstructure:"PROTECTED_API_PORT"`
	PublicApiPort          string `mapstructure:"PUBLIC_API_PORT"`
	HiddenApiPort          string `mapstructure:"HIDDEN_API_PORT"`
	LogLevel               string `mapstructure:"LOG_LEVEL"`
	RequestTimeoutDuration string `mapstructure:"REQUEST_TIMEOUT_DURATION"`
	WatcherSleepInterval   string `mapstructure:"WATCHER_SLEEP_INTERVAL"`
}

var service = &Feature{
	Name:       constants.FEATURE_SERVICE,
	Config:     &ServiceConfig{},
	enabled:    true,
	configured: false,
	ready:      false,
	requirements: []string{
		"Host",
		"ProtectedApiPort",
		"PublicApiPort",
		"HiddenApiPort",
		"LogLevel",
		"RequestTimeoutDuration",
		"WatcherSleepInterval",
	},
}

func init() {
	Features.Add(service)
}

From the example above, you can find a type ServiceConfig that states what env vars are to be expected. These are automatically read from the environment. Env vars must belong to a feature which can be toggled on or off. A feature can also define which env vars are required for it to start.

If you wish to disable a feature, you can mention it in the list of DISABLE_FEATURES var in run-time.

Reading the env vars is the job of pkg/config/envVars.go. Each config struct must be registered in envVars.go. The config struct is then automatically injected to its respective feature after initialisation.

It is possible to set a default value for each variable, this can be done in pkg/config/envVars.go under setDefaults().

By the time the CMD calls the Proc, all env vars should have already been read and injected into their features, making them available for the rest of the package.