edgevpn/pkg/utils/leader.go

// Copyright © 2022 Ettore Di Giacinto <[email protected]>
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License along
// with this program; if not, see <http://www.gnu.org/licenses/>.

package utils

import "hash/fnv"

func hash(s string) uint32 {
	h := fnv.New32a()
	h.Write([]byte(s))
	return h.Sum32()
}

func Leader(actives []string) string {
	// first get available nodes
	leaderboard := map[string]uint32{}

	leader := actives[0]

	// Compute who is leader at the moment
	for _, a := range actives {
		leaderboard[a] = hash(a)
		if leaderboard[leader] < leaderboard[a] {
			leader = a
		}
	}
	return leader
}