controller.go

package nucleus

import (
	"encoding/gob"
	"fmt"
	"os"

	"code.fbi.h-da.de/cocsn/gosdn/database"
	"github.com/google/uuid"
	log "github.com/sirupsen/logrus"
	"github.com/spf13/viper"
)

// Core is the representation of the controllers core
type Core struct {
	southboundInterfaces    map[string]SouthboundInterface
	principalNetworkDomains map[uuid.UUID]PrincipalNetworkDomain
	database                database.Database
	IsRunning               chan bool
}

//Initialize does start-up housekeeping like reading controller config files
func (c *Core) Initialize(IsRunningChannel chan bool) {
	// Set config defaults
	viper.SetDefault("socket", "localhost:55055")

	// Set config path and read config
	viper.SetConfigName("gosdn")
	viper.SetConfigType("toml")
	viper.AddConfigPath("/usr/local/etc/gosdn/")
	viper.AddConfigPath("./configs/")
	err := viper.ReadInConfig()
	if err != nil {
		log.Fatal(fmt.Errorf("Fatal error config file: %s \n", err))
	}
	path := viper.GetString("pnd.path")
	gob.Register(&pndImplementation{})
	gob.Register(&OpenConfig{})
	c.AttachDatabase()

	if err := c.loadPNDs(path); err != nil {
		log.Info(err)
	}

	c.IsRunning = IsRunningChannel
}

// AttachDatabase connects to the database and passes the connection to the controller core
func (c *Core) AttachDatabase() {
	c.database = database.NewDatabaseClient()
}

// TODO: the load and save functions for pnds are just temporary and should be
// moved to the database

// SavePNDs imports the PNDs from last session
func (c *Core) savePNDs(path string) error {
	f, err := os.Create(path)
	if err != nil {
		return err
	}
	defer f.Close()
	return gob.NewEncoder(f).Encode(c.principalNetworkDomains)
}

// loadPNDs imports the PNDs from last session
func (c *Core) loadPNDs(path string) error {
	f, err := os.Open(path)
	if err != nil {
		return err
	}
	defer f.Close()
	return gob.NewDecoder(f).Decode(&c.principalNetworkDomains)
}

// Shutdown waits for the shutdown signal and gracefully shuts down once it arrived
func (c *Core) Shutdown() {
	<-c.IsRunning
	log.Info("Received shutdown signal. Shutting down")

	err := viper.WriteConfig()
	if err != nil {
		log.Fatal(err)
	}
	log.Info("Shutdown complete")
	os.Exit(0)
}