configparser

Overview ¶

Package configparser contains the code required to fill a Go structure representing the configuration information from several sources like:

1. a struct containing the default values
2. a map from string to strings (e.g. the one that can be extracted for a Kubernetes ConfigMap)
3. an environment source like the system environment variables or a "fake" one suitable for testing.

To map the struct fields with the sources, the "env" tag is being used like in the following example:

type Data struct {
	// WebhookCertDir is the directory where the certificates for the webhooks
	// need to written. This is different between plain Kubernetes and OpenShift
	WebhookCertDir string `json:"webhookCertDir" env:"WEBHOOK_CERT_DIR"`

	// WatchNamespace is the namespace where the operator should watch and
	// is configurable via environment variables of via the OpenShift console
	WatchNamespace string `json:"watchNamespace" env:"WATCH_NAMESPACE"`
}

The ReadConfigMap function will look for an "WEBHOOK_CERT_DIR" entry inside the passed map or a corresponding environment variable. This function can be used to implement a method in the previous struct like in the following example:

func (config *Data) ReadConfigMap(data map[string]string) {
	configparser.ReadConfigMap(config, &Data{}, data, configparser.OsEnvironment{})
}