open-consul/lib/rtt.go

62 lines
1.8 KiB
Go

package lib
import (
"math"
"time"
"github.com/hashicorp/serf/coordinate"
)
// ComputeDistance returns the distance between the two network coordinates in
// seconds. If either of the coordinates is nil then this will return positive
// infinity.
func ComputeDistance(a *coordinate.Coordinate, b *coordinate.Coordinate) float64 {
if a == nil || b == nil {
return math.Inf(1.0)
}
return a.DistanceTo(b).Seconds()
}
// CoordinateSet holds all the coordinates for a given node, indexed by network
// segment name.
type CoordinateSet map[string]*coordinate.Coordinate
// Intersect tries to return a pair of coordinates which are compatible with the
// current set and a given set. We employ some special knowledge about network
// segments to avoid doing a full intersection, since this is in several hot
// paths. This might return nil for either coordinate in the output pair if an
// intersection cannot be found. The ComputeDistance function above is designed
// to deal with that.
func (cs CoordinateSet) Intersect(other CoordinateSet) (*coordinate.Coordinate, *coordinate.Coordinate) {
// Use the empty segment by default.
segment := ""
// If we have a single segment, then let our segment take priority since
// we are possibly a client. Any node with more than one segment can only
// be a server, which means it should be in all segments.
if len(cs) == 1 {
for s := range cs {
segment = s
}
}
// Likewise for the other set.
if len(other) == 1 {
for s := range other {
segment = s
}
}
return cs[segment], other[segment]
}
// GenerateCoordinate creates a new coordinate with the given distance from the
// origin. This should only be used for tests.
func GenerateCoordinate(rtt time.Duration) *coordinate.Coordinate {
coord := coordinate.NewCoordinate(coordinate.DefaultConfig())
coord.Vec[0] = rtt.Seconds()
coord.Height = 0
return coord
}