dnsmasq-netbox-connector/main.go

package main

import (
	"context"
	"fmt"
	"os"
	"strings"

	"git.faercol.me/faercol/dnsmasq-netbox-connector/internal/config"
	"git.faercol.me/faercol/dnsmasq-netbox-connector/internal/dnsmasq"
	"git.faercol.me/faercol/dnsmasq-netbox-connector/internal/healthchecks"
	"git.faercol.me/faercol/dnsmasq-netbox-connector/internal/netbox"
	gohealthchecks "git.faercol.me/faercol/go-healthchecks"
)

func main() {
	configPath := "/etc/dnmasq-netbox/config.json"

	if len(os.Args) > 1 {
		configPath = os.Args[1]
	}

	conf, err := config.New(configPath)
	if err != nil {
		fmt.Fprintf(os.Stderr, "Failed to read configuration: %s\n", err)
		os.Exit(1)
	}

	healtchecksClt := gohealthchecks.NewPingClient(conf.HostPingAPI)

	check, err := healthchecks.Start(context.Background(), conf.HealthchecksConfig, healtchecksClt)
	if err != nil {
		fmt.Fprintf(os.Stderr, "Failed to notify process start: %s\n", err)
	}

	leases, err := dnsmasq.GetDynamicLeases(conf.LeasesPath, conf.DHCPRangeStart, conf.DHCPRangeEnd)
	if err != nil {
		fmt.Fprintf(os.Stderr, "Failed to parse leases: %s\n", err)
		if err := healthchecks.Failure(context.Background(), conf.HealthchecksConfig, healtchecksClt, check, "failed to parse lease file"); err != nil {
			fmt.Fprintf(os.Stderr, "Failed to notify failure: %s\n", err)
		}
		os.Exit(1)
	}

	for _, l := range leases {
		fmt.Printf("Got lease %s\n", l)
	}

	netboxClt := netbox.New(*conf)
	assignedIP, freeIP, err := netboxClt.GetUsedDHCPAddresses(context.Background())
	if err != nil {
		fmt.Fprintf(os.Stderr, "Failed to get list of assigned IPs: %s\n", err)
		if err := healthchecks.Failure(context.Background(), conf.HealthchecksConfig, healtchecksClt, check, "failed to get assigned IPs"); err != nil {
			fmt.Fprintf(os.Stderr, "Failed to notify failure: %s\n", err)
		}
		os.Exit(1)
	}

	allInterfaces, err := netboxClt.GetAllInterfaces(context.Background())
	if err != nil {
		fmt.Fprintf(os.Stderr, "Failed to get list of interfaces: %s\n", err)
		if err := healthchecks.Failure(context.Background(), conf.HealthchecksConfig, healtchecksClt, check, "failed to get interfaces"); err != nil {
			fmt.Fprintf(os.Stderr, "Failed to notify failure: %s\n", err)
		}
		os.Exit(1)
	}

	toDelete, toAdd := reconcile(leases, assignedIP, freeIP, allInterfaces)
	for _, a := range toDelete {
		fmt.Printf("Following IP should be unassigned: %s\n", a.String())
	}
	for _, a := range toAdd {
		fmt.Printf("Following IP should be assigned: %s\n", a.String())
	}

	if err := netboxClt.UpdateIPs(context.Background(), toDelete, toAdd); err != nil {
		fmt.Fprintf(os.Stderr, "Failed to update IP assignment in netbox: %s\n", err)
		if err := healthchecks.Failure(context.Background(), conf.HealthchecksConfig, healtchecksClt, check, "failed to update assignment"); err != nil {
			fmt.Fprintf(os.Stderr, "Failed to notify failure: %s\n", err)
		}
		os.Exit(1)
	}

	if err := healthchecks.Success(context.Background(), conf.HealthchecksConfig, healtchecksClt, check); err != nil {
		fmt.Fprintf(os.Stderr, "Failed to notify process success: %s\n", err)
	}
}

// this method would probably require a bit of refacto, it's quite ugly
func reconcile(leases []*dnsmasq.Lease, assigned []*netbox.IP, free []*netbox.IP, interfaces []*netbox.Interface) (toDelete []*netbox.IP, toAdd []*netbox.IP) {
	dhcpMapping := map[string]string{}
	for _, l := range leases {
		dhcpMapping[l.IP.String()] = l.Mac
	}

	assignedMapping := map[string]string{}
	freeMapping := map[string]*netbox.IP{}

	interfaceMapping := map[string]*netbox.Interface{}
	for _, i := range interfaces {
		if i.MacAddress == "" {
			continue
		}
		interfaceMapping[strings.ToLower(i.MacAddress)] = i
	}

	for _, a := range assigned {
		assignedMapping[a.Address.Addr().String()] = ""
		_, ok := dhcpMapping[a.Address.Addr().String()]
		if !ok {
			toDelete = append(toDelete, a)
		}
	}
	for _, a := range free {
		freeMapping[a.Address.Addr().String()] = a
	}

	for _, l := range leases {
		_, ok := assignedMapping[l.IP.String()]
		if !ok {
			iface, ok := interfaceMapping[strings.ToLower(l.Mac)]
			if !ok {
				continue
			}
			ip, ok := freeMapping[l.IP.String()]
			if !ok {
				continue
			}
			ip.Interface = iface
			toAdd = append(toAdd, ip)
		}
	}

	return
}