func ReadConfigFromFile()

in confgenerator/config.go [164:196]
23 lines of code
6 McCabe index (conditional complexity)

func ReadConfigFromFile(ctx context.Context, path string) (*RunMonitoringConfig, error) {
	config := DefaultRunMonitoringConfig()

	// Fetch metadata from the available environment variables.
	config.Env = fetchMetadata()

	if _, err := os.Stat(path); err != nil {
		if os.IsNotExist(err) {
			log.Println("confgenerator: no user config file found, using default config")
			return config, nil
		}
		return nil, fmt.Errorf("failed to retrieve the user config file %q: %w", path, err)
	}

	data, err := ioutil.ReadFile(path)
	if err != nil {
		return nil, err
	}
	log.Printf("confgenerator: using RunMonitoring config:\n%s", string(data))

	// Unmarshal the user config over the default config. If some options are unspecified
	// the collector uses the default settings for those options. For example, if not specified
	// targetLabels is set to {"revision", "service", "configuration"}
	if err := yaml.UnmarshalContext(ctx, data, config, yaml.Strict()); err != nil {
		return nil, err
	}

	// Validate the RunMonitoring config
	if err := config.Validate(); err != nil {
		return nil, err
	}
	return config, nil
}