parseTemplateCreateConf.go

package templateCreate

import (
	"flag"
	"os"
	"strings"

	"github.com/sirupsen/logrus"
	"gopkg.in/yaml.v3"
)

var configPath_default = "templateCreate/templateCreate.clab_vars.yaml" // config path if no other path is given via -config flag
var tcConf *TemplateCreateConfig                                        // pointer to parsed config
// ipPrefix: ipBase without number after last ".".
// e.g. ipBase = "172.100.20.0" -> ipPrefix = "172.100.20.".
var ipPrefix string
var peerGenMode string
var curSubnetNr int

func ParseTemplateCreateConfig() {
	// TODO: flag validation
	configPath := flag.String("config", "", "path to the config file")
	logLevel := flag.String("log", "", "logrus log level (debug, info, warn, error, fatal, panic)")

	flag.Parse()

	logrus.SetFormatter(&logrus.TextFormatter{FullTimestamp: true})
	// parse string, this is built-in feature of logrus
	ll, err := logrus.ParseLevel(*logLevel)
	if err != nil {
		ll = logrus.InfoLevel
		logrus.Info("-log flag not provided, using default: ", ll)
	}
	// set global log level
	logrus.SetLevel(ll)
	logrus.Info("Setting log level to ", ll)

	// if no argument
	if *configPath == "" {
		err = flag.Set("config", configPath_default)
		if err != nil {
			ll = logrus.InfoLevel
			logrus.Info("-log flag not provided, using default: ", ll)
		}
		logrus.Info("-config flag not provided, using default: ", *configPath)
	}

	// unmarshal config
	config := &TemplateCreateConfig{}
	file, err := os.ReadFile(*configPath)
	if err != nil {
		logrus.Fatal(err)
	}
	if err := yaml.Unmarshal(file, config); err != nil {
		logrus.Fatal(err)
	}
	// set TemplateCreateConfig variable
	tcConf = config
	//logrus.Info(*tcConf) // print entire parsed config
	setConfVals()
}

func setConfVals() {
	peerGenMode = tcConf.PeerGen.Mode
	logrus.Infof("Generation mode is %v", peerGenMode)
	// IP without part after last dot, but including last dot
	// to add the subnet numbers to for individual IPs
	// e.g. ipBase: 172.100.20.4 -> ipPrefix: 172.100.20.
	ipPrefix = tcConf.General.IpBase[:strings.LastIndex(tcConf.General.IpBase, ".")+1]
	// the next free subnet number in the network
	// control nodes start from .1
	// e.g. 5 control nodes, xxx.xxx.xx.1 - xxx.xxx.xx.6 -> curSubnetNr = 6
	curSubnetNr = tcConf.General.ControlNodeCount + 1
}