serf.go

package lib

import (
	"time"

	"github.com/hashicorp/serf/serf"
)

// SerfDefaultConfig returns a Consul-flavored Serf default configuration,
// suitable as a basis for a LAN, WAN, segment, or area.
func SerfDefaultConfig() *serf.Config {
	base := serf.DefaultConfig()

	// This effectively disables the annoying queue depth warnings.
	base.QueueDepthWarning = 1000000

	// This enables dynamic sizing of the message queue depth based on the
	// cluster size.
	base.MinQueueDepth = 4096

	// This gives leaves some time to propagate through the cluster before
	// we shut down. The value was chosen to be reasonably short, but to
	// allow a leave to get to over 99.99% of the cluster with 100k nodes
	// (using https://www.serf.io/docs/internals/simulator.html).
	base.LeavePropagateDelay = 3 * time.Second

	return base
}

func GetSerfTags(serf *serf.Serf) map[string]string {
	tags := make(map[string]string)
	for tag, value := range serf.LocalMember().Tags {
		tags[tag] = value
	}

	return tags
}

func UpdateSerfTag(serf *serf.Serf, tag, value string) {
	tags := GetSerfTags(serf)
	tags[tag] = value

	serf.SetTags(tags)
}