main.go

package main

import (
	"flag"
	"fmt"
	"os"
	"strings"

	venvmanager "code.fbi.h-da.de/danet/gosdn/applications/venv-manager/venv-manager"
	"google.golang.org/grpc"
	"google.golang.org/grpc/credentials/insecure"
)

func main() {
	var dialConnectionURL string
	var yamlFilepath string
	var customContainerRegistryURL string
	dialOption := grpc.WithTransportCredentials(insecure.NewCredentials())

	flag.StringVar(&dialConnectionURL, "controller", "localhost:55055", "")
	flag.StringVar(&yamlFilepath, "file", "venv.clab.yaml", "")
	flag.StringVar(&customContainerRegistryURL, "registry", "", "")

	// Define own output of --help and parsing error, as some library also uses the flags library and adds there flags to ours, which is not intended.
	flag.Usage = func() {
		fmt.Printf("Usable flags of the venv-manager:\n\n")
		fmt.Println("--controller string\n\t Controller URL and Port. (Default: 'localhost:55055')")
		fmt.Println("--file string\n\t Filename of the resulting topology file. (Default: 'venv.clab.yaml')")
		fmt.Println("--registry string\n\t URL of the container registry to use. Keep in mind that cEOS images and prebuild linux images with the gnmi target are not available on dockerhub. (Default: dockerhub)")
		fmt.Println("--help\n\t Shows this help screen.")
	}
	flag.Parse()

	customContainerRegistryURL = ensureLastCharIsSlash(customContainerRegistryURL)

	fmt.Println("I will try to connect to goSDN located at", dialConnectionURL)
	venvManager := venvmanager.NewVenvManager(dialConnectionURL, dialOption, yamlFilepath, customContainerRegistryURL)

	err := venvManager.TestConnection()
	if err != nil {
		fmt.Println(err)
		fmt.Println("Can't reach controller, exiting.")
		os.Exit(1)
	}
	fmt.Println("Connection successful!")
	fmt.Println("Generating file...")

	err = venvManager.CreateTopologyFile()
	if err != nil {
		fmt.Println(err)
		fmt.Println("An error occurred, exiting.")
		os.Exit(1)
	}
	os.Exit(0)
}

// Ensures that the last char of a string is a slash, if this string is not empty.
func ensureLastCharIsSlash(inputString string) string {
	if len(inputString) == 0 {
		return inputString
	}

	if strings.HasSuffix(inputString, "/") {
		return inputString
	}

	return inputString + "/"
}