func handleOverride()

in lib/handler.go [82:121]
36 lines of code
10 McCabe index (conditional complexity)

func handleOverride(config *Config, message *DHCPMessage) (*DHCPServer, error) {
	if override, ok := config.Overrides[message.Mac.String()]; ok {
		// Checking if override is expired. If so, ignore it. Expiration field should
		// be a timestamp in the following format "2006/01/02 15:04 -0700".
		// For example, a timestamp in UTC would look as follows: "2017/05/06 14:00 +0000".
		var err error
		var expiration time.Time
		if override.Expiration != "" {
			expiration, err = time.Parse("2006/01/02 15:04 -0700", override.Expiration)
			if err != nil {
				glog.Errorf("Could not parse override expiration for MAC %s: %s", message.Mac.String(), err.Error())
				return nil, nil
			}
			if time.Now().After(expiration) {
				glog.Errorf("Override rule for MAC %s expired on %s, ignoring", message.Mac.String(), expiration.Local())
				return nil, nil
			}
		}
		if override.Expiration == "" {
			glog.Infof("Found override rule for %s without expiration", message.Mac.String())
		} else {
			glog.Infof("Found override rule for %s, it will expire on %s", message.Mac.String(), expiration.Local())
		}

		var server *DHCPServer
		if len(override.Host) > 0 {
			server, err = handleHostOverride(config, override.Host)
		} else if len(override.Tier) > 0 {
			server, err = handleTierOverride(config, override.Tier, message)
		}
		if err != nil {
			return nil, err
		}
		if server != nil {
			return server, nil
		}
		glog.Infof("Override didn't have host or tier, this shouldn't happen, proceeding with normal server selection")
	}
	return nil, nil
}